Rotating electric machine

Abstract

A rotating electric machine according to the present invention comprises: a rotor that can rotate about a central axis; a stator that is disposed radially inward of the rotor; a heat dissipation part that is disposed on one axial-direction side with respect to the rotor and the stator; and a heat transfer member that extends in the axial direction and connects the stator and the heat dissipation part. The stator has a stator core surrounding the central axis. The stator core is provided with a hole section recessed toward the other axial-direction side. A portion of the heat transfer member is positioned in the hole section.

Description

Rotating electrical machine

[0001] The present invention relates to a rotating electrical machine. This application claims priority based on Japanese Patent Application No. 2025-006141 filed in Japan on January 16, 2025, and incorporates its content herein.

[0002] An outer-rotor type motor in which a rotor is disposed on the radially outer side of a stator is known (for example, Patent Document 1).

[0003] Japanese Patent Application Laid-Open No. 2012-210105

[0004] In the above outer-rotor type motor, since the stator is surrounded by the rotor, it is difficult to radiate the heat generated in the stator to the outside of the motor. Therefore, in the above outer-rotor type motor, the temperature of the stator tends to be high, and it is difficult to suppress the deterioration of the stator.

[0005] One object of one aspect of the present invention is to provide a rotating electrical machine capable of suppressing the temperature of the stator from becoming too high.

[0006] One aspect of the rotating electrical machine of the present invention includes a rotor rotatable about a central axis, a stator disposed on the radially inner side of the rotor, a heat radiating portion disposed on one axial side with respect to the rotor and the stator, and a heat transfer member extending in the axial direction and connecting the stator and the heat radiating portion. The stator has a stator core surrounding the central axis. A hole portion recessed toward the other axial side is provided in the stator core. A part of the heat transfer member is located in the hole portion.

[0007] According to one aspect of the present invention, in a rotating electrical machine, it is possible to suppress the temperature of the stator from becoming too high.

[0008] Figure 1 is a first perspective view showing a rotating electric machine of the first embodiment. Figure 2 is a second perspective view showing a rotating electric machine of the first embodiment. Figure 3 is a cross-sectional view showing a rotating electric machine of the first embodiment. Figure 4 is a cross-sectional view showing a rotating electric machine of the first embodiment, taken along the line IV-IV of Figure 3. Figure 5 is a cross-sectional view showing a rotating electric machine of the first embodiment, taken along the line V-V of Figure 4. Figure 6 is a perspective view showing a part of the rotating electric machine of the first embodiment. Figure 7 is a cross-sectional view showing a rotating electric machine of the second embodiment.

[0009] The following description of a rotating electric machine according to an embodiment of the present invention will be made with reference to the drawings. Note that the scope of the present invention is not limited to the following embodiments, and modifications can be made as appropriate within the scope of the technical idea of ​​the present invention. Furthermore, in the following drawings, the scale and number of components may differ from the actual structure in order to make the components easier to understand.

[0010] Each figure shows the Z-axis. The Z-axis is the direction in which the central axis J of the rotating electric machine extends. In this embodiment, the central axis J is a virtual axis. In the following description, the direction in which the central axis J extends, that is, the direction parallel to the Z-axis, is referred to as the "axial direction." The radial direction centered on the central axis J is simply referred to as the "radial direction." The circumferential direction centered on the central axis J is simply referred to as the "circumferential direction." Of the axial directions, the side in which the Z-axis arrow points (+Z side) is referred to as the "one axial side" or "upper side." Of the axial directions, the side opposite to the side in which the Z-axis arrow points (-Z side) is referred to as the "other axial side" or "lower side." Note that the upper side and lower side are merely names used to describe the relative positional relationship of each part, and the actual arrangement may be different from the arrangement indicated by these names.

[0011] The circumferential direction is indicated by the arrow θ in each diagram. The side of the circumferential direction in which the arrow θ points (the +θ side) is called the "one side of the circumferential direction." The side of the circumferential direction opposite to the side in which the arrow θ points (the -θ side) is called the "other side of the circumferential direction." The one side of the circumferential direction is the side that proceeds clockwise around the central axis J when viewed from above. The other side of the circumferential direction is the side that proceeds counterclockwise around the central axis J when viewed from above.

[0012] <First Embodiment> The rotating electric machine 10 of this embodiment shown in Figure 1 is an outer rotor type motor. The rotating electric machine 10 is attached to a wheel 81 and a vehicle body (not shown) of a vehicle 80 such as an automobile, and is used as a drive device to rotate the wheel 81. The rotating electric machine 10 may have both the function of outputting power as an engine and the function of generating electricity as a generator.

[0013] As shown in Figure 2, the rotating electric machine 10 is substantially cylindrical in shape, extending axially around a central axis J. As shown in Figure 1, the rotating electric machine 10 is inserted into the wheel 81 and tire 82 from the inside of the vehicle 80, and a fixed part 48 that can rotate around the central axis J is fixed to the wheel 81 by a plurality of bolts 96. In this way, the rotating electric machine 10 transmits rotational torque to the wheel 81. Although not shown in the figures, the rotating electric machine 10 may be attached to each of the four wheels 81 of the vehicle 80, or it may be attached to only the two wheels 81 located on the front side of the vehicle 80, for example. As shown in Figure 3, the rotating electric machine 10 comprises a cylindrical part 20, an annular support part 26, a stator 30, a drive transmission part 40, a rotor 50, an impeller part 55, a heat dissipation part 60, and a sealing member 95. Also, as shown in Figure 5, the rotating electric machine 10 includes a heat transfer member 71.

[0014] As shown in Figure 3, the cylindrical portion 20 is cylindrical, extending axially around the central axis J. In this embodiment, the cylindrical portion 20 is substantially cylindrical, extending axially with the central axis J as its center. The cylindrical portion 20 has openings on both sides in the axial direction. The cylindrical portion 20 has an opening 20g that opens upward. The cylindrical portion 20 is positioned radially inward from the impeller portion 55 and the stator 30. The cylindrical portion 20 is radially opposite to the impeller portion 55 and the stator 30. The cylindrical portion 20 holds the stator 30. The cylindrical portion 20 also supports the drive transmission portion 40. The cylindrical portion 20 has a first cylindrical portion 21, a second cylindrical portion 22, a third cylindrical portion 23, and a fourth cylindrical portion 24. The first cylindrical portion 21, the second cylindrical portion 22, the third cylindrical portion 23, and the fourth cylindrical portion 24 are each part of the cylindrical portion 20 and are connected axially in this order from top to bottom. The cylindrical portion 20 is also provided with a first female screw hole 20a. As shown in Figure 4, the cylindrical portion 20 is provided with a recess 20e. As shown in Figure 5, the cylindrical portion 20 is provided with a through hole 20c.

[0015] As shown in Figure 3, the first cylindrical portion 21 is substantially annular in shape with respect to the central axis J. The upper end of the first cylindrical portion 21 is the upper end of the cylindrical portion 20. A sealing member 95 is fixed to the outer circumferential surface of the first cylindrical portion 21. In this embodiment, the sealing member 95 is an oil seal. The sealing member 95 may also be an O-ring. A lid portion 76 is attached to the inner circumferential surface of the first cylindrical portion 21. The lid portion 76 is substantially annular in shape with respect to the central axis J. The lid portion 76 closes the opening 20g.

[0016] The second cylindrical portion 22 is substantially annular in shape with a central axis J at its center. The upper end of the second cylindrical portion 22 is axially connected to the lower end of the first cylindrical portion 21. The second cylindrical portion 22 is positioned above the stator 30. The outer diameter of the second cylindrical portion 22 is larger than the outer diameter of the first cylindrical portion 21, and the inner diameter of the second cylindrical portion 22 is smaller than the inner diameter of the first cylindrical portion 21. The portion of the upper-facing surface of the second cylindrical portion 22 that is radially outward from the first cylindrical portion 21 supports the sealing member 95 from below. The portion of the upper-facing surface of the second cylindrical portion 22 that is radially inward from the first cylindrical portion 21 supports the lid portion 76 from below.

[0017] The third cylindrical portion 23 is substantially annular in shape with respect to the central axis J. The upper end of the third cylindrical portion 23 is axially connected to the lower end of the second cylindrical portion 22. The outer diameter of the third cylindrical portion 23 is smaller than the outer diameter of the second cylindrical portion 22, and the inner diameter of the third cylindrical portion 23 is larger than the inner diameter of the second cylindrical portion 22. A bearing 91 is mounted on the inner circumferential surface of the third cylindrical portion 23. The bearing 91 is substantially annular in shape with respect to the central axis J. In this embodiment, the bearing 91 is a rolling bearing. The bearing 91 may also be a sliding bearing.

[0018] The fourth cylindrical portion 24 is substantially annular in shape with the central axis J as its center. The lower end of the fourth cylindrical portion 24 is the lower end of the cylindrical portion 20. The upper end of the fourth cylindrical portion 24 is axially connected to the lower end of the third cylindrical portion 23. The outer diameter of the fourth cylindrical portion 24 is the same as the outer diameter of the third cylindrical portion 23. The inner diameter of the fourth cylindrical portion 24 is larger than the inner diameter of the third cylindrical portion 23. A stator 30 is fixed to the outer circumferential surface of the third cylindrical portion 23 and the outer circumferential surface of the fourth cylindrical portion 24.

[0019] The first female screw hole 20a is a female screw hole that is recessed downward from the upper surface of the cylindrical portion 20. The lower end of the first female screw hole 20a reaches the second cylindrical portion 22. The cylindrical portion 20 is provided with a plurality of first female screw holes 20a. Although not shown in the figures, in this embodiment, the cylindrical portion 20 is provided with four first female screw holes 20a. The number of first female screw holes 20a provided in the cylindrical portion 20 may be three or fewer, or five or more. Each first female screw hole 20a is provided spaced apart from each other along the circumferential direction.

[0020] As shown in Figure 4, the recess 20e is a recess that extends radially inward from the outer circumferential surface of the cylindrical portion 20. Viewed from the axial direction, the recess 20e is substantially rectangular in shape. The cylindrical portion 20 is provided with a plurality of recesses 20e. In this embodiment, the cylindrical portion 20 is provided with four recesses 20e. Each recess 20e is provided at intervals from one another along the circumferential direction. In this embodiment, each recess 20e is provided at substantially equal intervals from one another along the circumferential direction. As shown in Figure 5, the upper end of each recess 20e is located below the upper end of the second cylindrical portion 22. The lower end of each recess 20e is the lower end of the cylindrical portion 20.

[0021] The through-hole 20c is a hole that penetrates the cylindrical portion 20 in the axial direction. Viewed from the axial direction, the through-hole 20c is substantially circular in shape. Although not shown in the figures, in this embodiment, the cylindrical portion 20 is provided with four through-holes 20c. Each through-hole 20c is spaced apart from each other along the circumferential direction. In this embodiment, each through-hole 20c is spaced substantially equally apart from each other along the circumferential direction. Viewed from the axial direction, each through-hole 20c overlaps with a different recess 20e. The lower end of each through-hole 20c is connected to the inner surface of a different recess 20e. Different heat transfer members 71 are passed through each through-hole 20c in the axial direction.

[0022] As shown in Figure 3, the annular support portion 26 is approximately circular with respect to the central axis J. The annular support portion 26 is located below the cylindrical portion 20. The annular support portion 26 is fixed to the fourth cylindrical portion 24 by a number of bolts (not shown). The outer diameter of the annular support portion 26 is larger than the outer diameter of the fourth cylindrical portion 24. The portion of the annular support portion 26 facing upward that is radially outward from the fourth cylindrical portion 24 supports the stator 30 from below. This determines the axial position of the stator 30.

[0023] The stator 30 is annular in shape surrounding the central axis J. In this embodiment, the stator 30 is substantially annular in shape surrounding the central axis J. The stator 30 surrounds the cylindrical portion 20 from the radially outer side. The stator 30 is fixed to the cylindrical portion 20. The stator 30 is positioned radially inward of the rotor 50. The stator 30 has a stator core 31, an insulator 35, and a plurality of coil portions 36.

[0024] The stator core 31 is annular in shape, surrounding the central axis J. In this embodiment, the stator core 31 is substantially annular in shape, surrounding the central axis J. The stator core 31 surrounds the cylindrical portion 20 from the radially outer side. As shown in Figure 4, the stator core 31 has a core back portion 32, a teeth portion 33, and a core projection portion 34.

[0025] The core back portion 32 is substantially annular in shape with the central axis J at its center. As shown in Figure 3, the inner circumferential surface of the core back portion 32 is fixed to the outer circumferential surface of the cylindrical portion 20. More specifically, the inner circumferential surface of the core back portion 32 is fixed to the outer circumferential surface of the third cylindrical portion 23 and the outer circumferential surface of the fourth cylindrical portion 24. As a result, the stator 30 is fixed to the cylindrical portion 20.

[0026] As shown in Figure 4, the teeth portion 33 protrudes radially outward from the outer circumferential surface of the core back portion 32. Viewed from the axial direction, the teeth portion 33 is substantially rectangular in shape, with its longer side extending radially. The teeth portion 33 faces the rotor 50 with a radial gap between them. In this embodiment, the stator core 31 has 24 teeth portions 33. The number of teeth portions 33 in the stator core 31 may be 23 or less, or 25 or more. Each tooth portion 33 is arranged with a gap between them along the circumferential direction.

[0027] The core protrusions 34 project radially inward from the core back portion 32. Viewed from the axial direction, the core protrusions 34 are substantially rectangular in shape, with their longer sides extending in the circumferential direction. In this embodiment, the stator core 31 has four core protrusions 34. Each core protrusion 34 is spaced apart from each other along the circumferential direction. In this embodiment, each core protrusion 34 is spaced substantially equally apart from each other along the circumferential direction. Each core protrusion 34 is located inside different recesses 20e of the cylindrical portion 20. The circumferential-facing surface of each core protrusion 34 is in contact with the circumferential-facing surface of the recess 20e. This determines the circumferential position of the stator core 31 relative to the cylindrical portion 20. Each core protrusion 34 is provided with a hole 34a. Thus, the stator core 31 is provided with a plurality of holes 34a.

[0028] As shown in Figure 5, each hole 34a is a hole that is recessed downward from the surface facing the upper side of the core protrusion 34. That is, the stator core 31 is provided with holes 34a that are recessed downward, i.e., on the other side in the axial direction. In this embodiment, each hole 34a is a hole that penetrates the core protrusion 34 in the axial direction. Each hole 34a does not have to penetrate the core protrusion 34 in the axial direction. As shown in Figure 4, different heat transfer members 71 are inserted in the axial direction into each hole 34a. As a result, at least a portion of the heat transfer members 71 is located in the hole 34a. In this embodiment, each of the multiple holes 34a is provided at equal intervals from each other along the circumferential direction. As a result, each of the multiple heat transfer members 71 is arranged at equal intervals from each other along the circumferential direction.

[0029] The insulator 35 shown in Figure 3 insulates the stator core 31 from the coil portion 36. In this embodiment, the insulator 35 is made of resin. The insulator 35 has insulating properties. The stator 30 has a plurality of insulators 35. Each insulator 35 is mounted on a different tooth portion 33.

[0030] Each of the multiple coil sections 36 is mounted on a different tooth section 33 via an insulator 35. As shown in Figure 4, in this embodiment, the stator 30 has 24 coil sections 36. The number of coil sections 36 in the stator 30 may be 23 or less, or 25 or more. Each coil section 36 is spaced apart from each other in the circumferential direction. In this embodiment, the multiple coil sections 36 include a plurality of U-phase coils, a plurality of V-phase coils, and a plurality of W-phase coils. Each U-phase coil, each V-phase coil, and each W-phase coil is supplied with an alternating current from a current supply unit (not shown) with an electrical angle shifted by 120° from each other. When current is supplied to each coil section 36, each coil section 36 constitutes an electromagnet with its magnetic poles facing radially.

[0031] The drive transmission unit 40 shown in Figure 3 transmits the rotational torque of the rotor 50 to the wheel 81 of the vehicle 80 shown in Figure 1. The drive transmission unit 40 is fixed to the rotor 50 by bolts 92. In this way, the drive transmission unit 40 is connected to the rotor 50. The drive transmission unit 40 is rotatable together with the rotor 50 about the central axis J. As shown in Figure 3, the drive transmission unit 40 has a shaft portion 41 and a fixed portion 48.

[0032] The shaft portion 41 is columnar in shape and extends axially along the central axis J. In this embodiment, the shaft portion 41 is substantially cylindrical in shape and extends axially with respect to the central axis J. The shaft portion 41 passes through the inside of the cylindrical portion 20 in the axial direction. The shaft portion 41 has a first shaft portion 42, a second shaft portion 43, a third shaft portion 44, and a fourth shaft portion 45. Each of the first shaft portion 42, the second shaft portion 43, the third shaft portion 44, and the fourth shaft portion 45 is a part of the shaft portion 41 and is connected in this order axially from top to bottom. The shaft portion 41 is also provided with a shaft hole portion 41a.

[0033] The first shaft portion 42 is substantially cylindrical in shape, extending axially with respect to the central axis J. The upper end of the first shaft portion 42 is the upper end of the shaft portion 41. The first shaft portion 42 passes through the interior of the cover portion 76 in the axial direction. An oil seal 94 is attached to the outer circumferential surface of the first shaft portion 42. The oil seal 94 is substantially annular in shape with respect to the central axis J. The outer circumferential surface of the oil seal 94 is in contact with the inner circumferential surface of the cover portion 76. The oil seal 94 seals the space between the cover portion 76 and the shaft portion 41. This prevents foreign matter such as moisture and dust from entering the interior of the rotating electric machine 10 through the space between the cover portion 76 and the shaft portion 41.

[0034] The second shaft portion 43 is substantially cylindrical in shape and extends axially around the central axis J. The upper end of the second shaft portion 43 is connected axially to the lower end of the first shaft portion 42. The second shaft portion 43 is located inside the third cylindrical portion 23. The outer diameter of the second shaft portion 43 is larger than the outer diameter of the first shaft portion 42. The outer circumferential surface of the second shaft portion 43 is supported by a bearing 91 so as to be rotatable about the central axis J. As a result, the drive transmission portion 40 is rotatable about the central axis J.

[0035] The third shaft portion 44 is substantially annular in shape with the central axis J as its center. The upper end of the third shaft portion 44 is axially connected to the lower end of the second shaft portion 43. The third shaft portion 44 is positioned below the bearing 91. The outer diameter of the third shaft portion 44 is larger than the outer diameter of the second shaft portion 43. The upper-facing surface of the third shaft portion 44 supports the inner ring of the bearing 91 from below. This applies preload to the bearing 91.

[0036] The fourth shaft portion 45 is approximately annular in shape with the central axis J as its center. The upper end of the fourth shaft portion 45 is axially connected to the lower end of the third shaft portion 44. The lower end of the fourth shaft portion 45 is the lower end of the shaft portion 41. The lower end of the fourth shaft portion 45 is located below the stator 30. The outer diameter of the fourth shaft portion 45 is larger than the outer diameter of the third shaft portion 44.

[0037] The shaft hole 41a is a recessed hole that extends downward from the upper surface of the shaft portion 41. Although not shown in the illustration, the shaft hole 41a is approximately circular when viewed from the axial direction. Although not shown in the illustration, a shaft portion of a vehicle body (not shown) is inserted into the shaft hole 41a. In this embodiment, the shaft portion is fixed to the shaft hole 41a. As a result, the rotating electric machine 10 is fixed to the vehicle body.

[0038] The fixing portion 48 is plate-shaped and extends in a direction perpendicular to the axial direction. The plate surface of the fixing portion 48 faces in the axial direction. In this embodiment, the fixing portion 48 is substantially disc-shaped with the central axis J as its center. In the axial direction, the fixing portion 48 is positioned below the shaft portion 41, the rotor 50, and the stator 30, i.e., on the other side in the axial direction. The fixing portion 48 is connected to the lower end of the shaft portion 41 in the axial direction. As shown in Figure 1, the fixing portion 48 is fixed to the rotor 50 by a plurality of bolts 92. As a result, the drive transmission portion 40 can rotate together with the rotor 50 about the central axis J. The fixing portion 48 is provided with a plurality of second female screw holes 48a.

[0039] Each second female screw hole 48a is a female screw hole recessed upward from the downward-facing surface of the fixing part 48. Each second female screw hole 48a is spaced apart from each other along the circumferential direction. When multiple bolts 96 are passed axially through different wheel holes 81a provided in the wheel 81 and tightened into different second female screw holes 48a, the fixing part 48 is fixed to the wheel 81. Therefore, when the drive transmission unit 40 rotates together with the rotor 50 around the central axis J, the rotational torque of the rotor 50 is transmitted to the wheel 81. As a result, the rotating electric machine 10 rotates the wheel 81.

[0040] As shown in Figure 3, the rotor 50 is cylindrical, surrounding the central axis J. In this embodiment, the rotor 50 is substantially cylindrical with respect to the central axis J. The rotor 50 is positioned radially outward from the stator 30. The rotor 50 surrounds the stator 30 from the radially outward. The rotor 50 faces the stator 30 with a radial gap between them. The rotor 50 is rotatable about the central axis J. The rotor 50 includes a holding portion 51, a rotor core 52, and a magnet 53.

[0041] The retaining portion 51 is substantially cylindrical in shape with respect to the central axis J. The retaining portion 51 surrounds the rotor core 52 from the radially outer side. In this embodiment, the retaining portion 51 is made of aluminum and a non-magnetic metal such as copper. This suppresses the flow of magnetic flux from the rotor core 52 into the retaining portion 51. The retaining portion 51 may also be made of resin. The upper end of the retaining portion 51 is located above both the rotor core 52 and the stator 30. The lower end of the retaining portion 51 is located below both the rotor core 52 and the stator 30. The lower end of the retaining portion 51 is fixed to the fixing portion 48 by a plurality of bolts 92. This connects the drive transmission portion 40 to the rotor 50. The retaining portion 51 is provided with a retaining recess 51a and a third female screw hole 51c.

[0042] The retaining recess 51a is a recess that extends radially outward from the inner circumferential surface of the retaining portion 51. The retaining recess 51a extends around the entire circumference. The retaining recess 51a is open to the bottom. Each of the multiple third female screw holes 51c is a female screw hole that extends upward from the surface facing downward of the retaining recess 51a. The retaining portion 51 is provided with multiple third female screw holes 51c. Although not shown in the figures, in this embodiment the retaining portion 51 is provided with 24 third female screw holes 51c. The number of third female screw holes 51c provided in the retaining portion 51 may be 23 or less, or 25 or more. Each third female screw hole 51c is provided spaced apart from each other along the circumferential direction.

[0043] As shown in FIG. 4, the rotor core 52 is annular and surrounds the central axis J. In the present embodiment, the rotor core 52 has a substantially annular shape centered on the central axis J. As shown in FIG. 3, the rotor core 52 is disposed inside the holding recess 51a. The rotor core 52 is provided with through holes 52a.

[0044] The through holes 52a are holes that penetrate the rotor core 52 in the axial direction. As shown in FIG. 4, when viewed from the axial direction, the through holes 52a are substantially circular. In the present embodiment, the rotor core 52 is provided with 24 through holes 52a. Each of the through holes 52a is arranged at intervals along the circumferential direction. As shown in FIG. 3, when viewed from the axial direction, each of the through holes 52a overlaps with a different third female screw hole 51c. When a plurality of bolts 98 are passed through different through holes 52a in the axial direction and tightened into the third female screw holes 51c, the rotor core 52 is fixed to the holding portion 51. Thereby, the holding portion 51 holds the rotor core 52. Note that the rotor core 52 may be adhesively fixed to the holding portion 51 with an adhesive, for example.

[0045] The magnet 53 is fixed to the inner peripheral surface of the rotor core 52. Thereby, the magnet 53 is attached to the rotor core 52. The magnet 53 is opposed to the stator core 31 with a radial gap therebetween. As shown in FIG. 4, in the present embodiment, the rotor 50 has 32 magnets 53. The number of magnets 53 included in the rotor 50 may be 31 or less, or may be 33 or more. Each of the magnets 53 is arranged at intervals along the circumferential direction.

[0046] As described above, when current is supplied to each coil portion 36, each coil portion 36 constitutes an electromagnet with its magnetic poles facing in the radial direction. When an electromagnet is formed in each coil portion 36, an electromagnetic force is applied to each magnet 53 of the rotor 50. When alternating currents with electrical angles shifted from each other by 120° are supplied to each U-phase coil, each V-phase coil, and each W-phase coil, an electromagnetic force in the circumferential direction is applied to each magnet 53 of the rotor 50, so the rotor 50 rotates about the central axis J. Thereby, the drive transmission portion 40 rotates about the central axis J together with the rotor 50.

[0047] When current is supplied to each coil portion 36, Joule heat is generated in each coil portion 36. The Joule heat generated in each coil portion 36 is transmitted to the stator core 31 through the insulator 35, and the temperature of the entire stator 30 rises. If the temperature of the stator 30 becomes too high, the performance of the insulator 35 with a low heat resistance temperature and the insulating coating of the coil portion 36 deteriorates, so there is a risk that the operation of the rotating electrical machine 10 becomes unstable. Therefore, in order to stabilize the operation of the rotating electrical machine 10, it is necessary to suppress the temperature of the stator 30 from becoming too high.

[0048] Also, when the rotor 50 rotates about the central axis J, the amount of magnetic flux passing through each magnet 53 changes, so eddy currents are generated in each magnet 53. Thereby, when the rotor 50 rotates, Joule heat is generated in each magnet 53, and the temperature of each magnet 53 rises. If the temperature of each magnet 53 becomes too high, each magnet 53 is demagnetized, so there is a risk that the electromagnetic force applied to each magnet 53 decreases. Thereby, if the temperature of each magnet 53 becomes too high, there is a risk that the drive efficiency of the rotating electrical machine 10 decreases. Therefore, in order to suppress a decrease in the drive efficiency of the rotating electrical machine 10, it is necessary to suppress the temperature of each magnet 53 from becoming too high.

[0049] As shown in Figure 3, the impeller portion 55 is annular in shape surrounding the central axis J. In this embodiment, the impeller portion 55 is substantially annular in shape with the central axis J as the center. In this embodiment, the impeller portion 55 is made of a non-magnetic metal. The impeller portion 55 may also be made of resin. In the axial direction, the impeller portion 55 is positioned between the stator 30 and the heat dissipation portion 60. The impeller portion 55 is positioned above the rotor 50. The radially outer portion of the impeller portion 55 is connected to the upper end of the holding portion 51. This allows the impeller portion 55 to rotate together with the rotor 50 about the central axis J. In this embodiment, the holding portion 51 and the impeller portion 55 are parts of the same single member. In this embodiment, the holding portion 51 and the impeller portion 55 are connected to each other. As shown in Figure 6, the impeller portion 55 has an annular plate 56, a connecting portion 57, and a plurality of blades 58.

[0050] The annular plate 56 is an annular shape that extends in a direction perpendicular to the axial direction. In this embodiment, the annular plate 56 is a substantially circular annular shape centered on the central axis J. As shown in Figure 3, the radially outer portion of the annular plate 56 is connected to the holding portion 51. The radially inner edge of the annular plate 56 is located radially inward from the magnet 53.

[0051] The connecting portion 57 is cylindrical and protrudes upward from the radial inner edge of the annular plate 56. In this embodiment, the connecting portion 57 is substantially cylindrical and protrudes axially with respect to the central axis J. The connecting portion 57 faces the first cylindrical portion 21 with a radial gap between them. As a result, the impeller portion 55 faces the cylindrical portion 20 with a radial gap between them. The inner circumferential surface of the connecting portion 57 is in contact with the sealing member 95. As described above, the sealing member 95 is fixed to the outer circumferential surface of the first cylindrical portion 21. Thus, the sealing member 95 seals the space between the impeller portion 55 and the cylindrical portion 20.

[0052] As shown in Figure 6, each of the multiple blades 58 is plate-shaped and protrudes radially outward from the connecting portion 57. The plate surface of each blade 58 faces circumferentially. The surface of each blade 58 facing downward is connected to the annular plate 56. Each blade 58 is spaced apart from one another along the circumferential direction. In this embodiment, each blade 58 is curved so that it is located on the other side of the circumferential direction (-θ side) as it moves radially outward. Each blade 58 may also be curved so that it is located on one side of the circumferential direction (+θ side) as it moves radially outward. When the impeller portion 55 rotates together with the rotor 50 around the central axis J, air is blown by each blade 58. The airflow AF shown by dashed arrows in Figures 3 and 5 is the flow of air blown by each blade 58. In this embodiment, when the impeller portion 55 rotates around the central axis J, an airflow AF facing radially outward is formed by each blade 58.

[0053] As shown in Figure 2, the heat dissipation section 60 is annular in shape surrounding the central axis J. In this embodiment, the heat dissipation section 60 is substantially annular in shape centered on the central axis J. The heat dissipation section 60 is made of metal. In this embodiment, the heat dissipation section 60 is made of aluminum. The material constituting the heat dissipation section 60 may be other metals such as copper and iron-based alloys. As shown in Figure 3, the heat dissipation section 60 is positioned above the rotor 50 and the stator 30, i.e., on one side in the axial direction. The heat dissipation section 60 is also positioned above the impeller section 55 and the cylindrical section 20, respectively. As shown in Figure 2, the heat dissipation section 60 has an annular section 61, a top wall section 62, and a plurality of ribs 64.

[0054] The annular portion 61 is approximately circular with respect to the central axis J. As shown in Figure 3, the inner diameter of the annular portion 61 is larger than the outer diameter of the lid portion 76. The outer diameter of the annular portion 61 is approximately the same as the inner diameter of the impeller portion 55. The annular portion 61 is in axial contact with the upper surface of the cylindrical portion 20. This determines the axial position of the heat dissipation portion 60 relative to the cylindrical portion 20. A through hole 61c is provided in the annular portion 61. As shown in Figure 5, a hole 61a is provided in the annular portion 61.

[0055] As shown in Figure 3, the through-hole 61c is a hole that penetrates the annular portion 61 in the axial direction. As shown in Figure 2, when viewed from the axial direction, the through-hole 61c is substantially circular in shape. In this embodiment, the annular portion 61 is provided with four through-holes 61c. Each through-hole 61c is spaced apart from the others along the circumferential direction. As shown in Figure 3, when viewed from the axial direction, each through-hole 61c overlaps with a different first female screw hole 20a. When multiple bolts 93 are passed through the different through-holes 61c in the axial direction and tightened into the first female screw holes 20a, the annular portion 61 is fixed to the cylindrical portion 20. As a result, the heat dissipation portion 60 is fixed to the cylindrical portion 20.

[0056] As shown in Figure 5, the hole 61a is a hole that penetrates the annular portion 61 in the axial direction. As shown in Figure 2, when viewed from the axial direction, the hole 61a is substantially circular in shape. In this embodiment, the annular portion 61 is provided with four holes 61a. Each hole 61a is provided spaced apart from each other along the circumferential direction. As shown in Figure 5, when viewed from the axial direction, each hole 61a overlaps with each of the different insertion holes 20c and each of the different holes 34a.

[0057] As shown in Figure 2, the top wall portion 62 is an annular shape that protrudes radially outward from the radial outer edge of the annular portion 61. The top wall portion 62 surrounds the central axis J. In this embodiment, the top wall portion 62 is a substantially annular plate shape centered on the central axis J. As shown in Figure 3, the top wall portion 62 is positioned above the impeller portion 55. The top wall portion 62 faces the impeller portion 55 with an axial gap between them. As shown in Figure 2, an air intake port 63 is provided in the top wall portion 62.

[0058] The air intake port 63 is a hole that penetrates the top wall portion 62 in the axial direction. Viewed from the axial direction, the air intake port 63 is roughly annular in shape, surrounding the central axis J. As shown in Figures 3 and 5, the air intake port 63 is located above the impeller portion 55. Therefore, when the rotor 50 and the impeller portion 55 rotate about the central axis J, the air above the top wall portion 62 flows into the impeller portion 55 through the air intake port 63 and then flows radially outward. In other words, by rotating the impeller portion 55 about the central axis J, air can be blown into the interior of the heat dissipation portion 60 through the air intake port 63. This increases the airflow velocity near the upper surface of the top wall portion 62, the lower surface of the top wall portion 62, and the inner surface of the air intake port 63, thereby suitably increasing the amount of heat transferred from the heat dissipation portion 60 to the airflow AF blown by the impeller portion 55. Therefore, the amount of heat dissipated from the heat dissipation section 60 to the outside of the rotating electric machine 10 can be suitably increased.

[0059] As shown in Figure 2, the multiple ribs 64 are plate-shaped and extend radially. The plate surface of each rib 64 faces circumferentially. Each rib 64 connects the radially outward-facing surface of the intake port 63 to the radially inward-facing surface of the intake port 63. Each of the multiple ribs 64 is spaced apart from one another along the circumferential direction. As a result, the intake port 63 is divided into multiple intake holes 65 by the multiple ribs 64. Therefore, in this embodiment, the surface area of ​​the heat dissipation section 60 can be increased compared to the case where the heat dissipation section 60 does not have multiple ribs 64. This increases the contact area between the air flowing through the upper surface of the top wall section 62, the lower surface of the top wall section 62, and the inside of each intake hole 65 and the heat dissipation section 60. Therefore, the amount of heat transferred from the heat dissipation section 60 to the airflow AF blown by the impeller section 55 can be more effectively increased. Therefore, the amount of heat dissipated from the heat dissipation section 60 to the outside of the rotating electric machine 10 can be more effectively increased. In this embodiment, the heat dissipation section 60 does not necessarily have to have multiple ribs 64.

[0060] As shown in Figure 5, the heat transfer member 71 is a member that extends in the axial direction. As shown in Figure 6, the rotating electric machine 10 is equipped with a plurality of heat transfer members 71. In this embodiment, the rotating electric machine 10 is equipped with four heat transfer members 71. The number of heat transfer members 71 equipped in the rotating electric machine 10 may be three or fewer, or five or more. Each heat transfer member 71 is arranged at equal intervals along the circumferential direction. The intervals between heat transfer members 71 that are arranged adjacent to each other in the circumferential direction may differ. As shown in Figure 5, each heat transfer member 71 is passed through different through holes 20c in the axial direction. The lower portion of each heat transfer member 71 is located inside the hole 34a provided in the stator core 31. In other words, a part of each heat transfer member 71 is located inside the hole 34a. As a result, heat from the stator core 31 is suitably transferred to each heat transfer member 71. In this embodiment, the lower end of each heat transfer member 71 is located at the lower end of the hole 34a. This allows heat from the entire axial direction of the stator core 31 to be suitably transferred to each heat transfer member 71. The upper portion of each heat transfer member 71 is located inside the holes 61a provided in the heat dissipation section 60. As a result, the heat transfer member 71 connects the stator 30 and the heat dissipation section 60. Therefore, heat generated in the stator 30 can be suitably transferred to the heat dissipation section 60 via the heat transfer member 71.

[0061] In this embodiment, the heat transfer member 71 is a cylindrical heat pipe extending in the axial direction. The heat transfer member 71 contains a working fluid (not shown) inside a metal pipe. The material used to make up the pipe can be a metal such as copper or aluminum. In this embodiment, the pipe is made of copper. The material used for the working fluid can be a liquid such as water or ethanol. In this embodiment, the working fluid is water. Thus, the heat transfer member 71 is made of a non-magnetic material. The working fluid absorbs heat from the stator 30 inside the stator core 31 and vaporizes, and then transfers heat to the heat dissipation section 60 inside the heat dissipation section 60 and condenses. This makes it possible to increase the thermal conductivity of the heat transfer member 71 compared to the case where the heat transfer member 71 is a metal columnar or cylindrical member. Therefore, the amount of heat transferred from the stator 30 to the heat dissipation section 60 via the heat transfer member 71 can be suitably increased. Note that the heat transfer member 71 may also be a metal columnar or cylindrical member. In this case, it is preferable that the material constituting the heat transfer member 71 is a non-magnetic material such as copper and aluminum.

[0062] It is preferable that thermal conductive grease is filled between the inner surface of the hole 34a and the heat transfer member 71. This reduces the thermal resistance between the inner surface of the hole 34a and the heat transfer member 71, thereby more effectively increasing the amount of heat transferred from the stator 30 to the heat transfer member 71. It is also preferable that thermal conductive grease is filled between the inner surface of the hole 61a and the heat transfer member 71. This reduces the thermal resistance between the inner surface of the hole 61a and the heat transfer member 71, thereby more effectively increasing the amount of heat transferred from the heat transfer member 71 to the heat dissipation section 60.

[0063] The first heat flow TF1, shown by the solid arrow in Figure 5, represents the flow of heat dissipated from the stator 30 to the outside of the rotating electric machine 10 via the heat transfer member 71 and the heat dissipation section 60. Heat generated in the stator 30, such as Joule heat generated in the multiple coil sections 36, is transferred to the annular section 61 of the heat dissipation section 60 via the heat transfer member 71. The heat transferred to the annular section 61 is then transferred to the top wall section 62. In this way, the heat generated in the stator 30 is dissipated to the outside of the rotating electric machine 10 via the heat transfer member 71 and the heat dissipation section 60. Therefore, compared to the case where the rotating electric machine 10 does not have a heat transfer member 71, the amount of heat dissipated from the stator 30 to the outside of the rotating electric machine 10 can be suitably increased. Furthermore, in this embodiment, as described above, the impeller section 55 can blow air into the heat dissipation section 60 via the air intake port 63, thus allowing for a favorable increase in the amount of heat transferred from the heat dissipation section 60 to the airflow AF blown by the impeller section 55. Therefore, the amount of heat dissipated from the stator 30 to the outside of the rotating electric machine 10 can be more favorably increased. Moreover, in this embodiment, as described above, since the heat dissipation section 60 has a plurality of ribs 64, the contact area between the airflow AF blown by the impeller section 55 and the heat dissipation section 60 can be increased. Therefore, the amount of heat dissipated from the stator 30 to the outside of the rotating electric machine 10 can be more favorably increased.

[0064] The second heat flow TF2, indicated by the solid arrow in Figure 5, represents the heat flow from the magnet 53 to the outside of the rotating electric machine 10 via the rotor core 52, the holding part 51, and the impeller part 55. A portion of the heat transferred from the magnet 53 to the holding part 51 is dissipated to the outside of the rotating electric machine 10 via the outer circumferential surface of the holding part 51. In this embodiment, the heat transferred from the holding part 51 to the impeller part 55 is dissipated into the airflow AF passing through the impeller part 55. This allows for a more favorable increase in the amount of heat dissipated from the magnet 53 to the outside of the rotating electric machine 10 via the airflow AF passing through the impeller part 55.

[0065] According to this embodiment, the rotating electric machine 10 includes a rotor 50 that can rotate about a central axis J, a stator 30 arranged radially inward of the rotor 50, a heat dissipation section 60 arranged above the rotor 50 and stator 30, i.e., on one side in the axial direction, and a heat transfer member 71 that extends in the axial direction and connects the stator 30 and the heat dissipation section 60. The stator 30 has a stator core 31 surrounding the central axis J, and the stator core 31 is provided with a hole 34a recessed on the lower side, i.e., on the other side in the axial direction, and a part of the heat transfer member 71 is located in the hole 34a. Therefore, as described above, heat generated in the stator 30 can be suitably transferred to the heat dissipation section 60 via the heat transfer member 71. Furthermore, since the heat dissipation section 60 is arranged above the rotor 50 and stator 30, the outer surface of the heat dissipation section 60 is exposed to the outside of the rotating electric machine 10. These features allow for a suitable increase in the amount of heat dissipated from the stator 30 to the outside of the rotating electric machine 10 via the heat transfer member 71 and the heat dissipation section 60. Therefore, it is possible to suppress the temperature of the stator 30 from becoming too high, and thus prevent the deterioration of the stator 30.

[0066] Furthermore, in this embodiment, since a portion of the heat transfer member 71 is located in the hole 34a, heat from the entire axial direction of the stator core 31 can be suitably transferred to the heat transfer member 71. This makes it easier to reduce variations in the amount of heat transferred from the stator 30 to the heat transfer member 71 in the axial direction. Therefore, it is possible to suppress the temperature of a portion of the stator 30 in the axial direction from becoming too high. Consequently, deterioration of the stator 30 can be more effectively suppressed.

[0067] According to this embodiment, the rotating electric machine 10 is equipped with an impeller section 55 positioned between the stator 30 and the heat dissipation section 60, which is rotatable together with the rotor 50 around a central axis J. The heat dissipation section 60 has a top wall section 62 surrounding the central axis J, and the top wall section 62 is provided with an air intake port 63 that penetrates the top wall section 62 in the axial direction. As a result, as described above, the rotation of the impeller section 55 around the central axis J allows air to be blown into the interior of the heat dissipation section 60 via the air intake port 63. This allows for a favorable increase in the amount of heat transferred from the heat dissipation section 60 to the airflow AF blown by the impeller section 55. Consequently, the amount of heat dissipated from the stator 30 to the outside of the rotating electric machine 10 via the heat dissipation section 60 can be more favorably increased, thus more favorably preventing the temperature of the stator 30 from becoming too high.

[0068] According to this embodiment, the rotor 50 has an annular rotor core 52 surrounding a central axis J, a magnet 53 attached to the rotor core 52, and a holding portion 51 that surrounds the rotor core 52 from the radially outer side and holds the rotor core 52, and the holding portion 51 and the impeller portion 55 are parts of the same single member. Therefore, compared to the case where the holding portion 51 and the impeller portion 55 are different and separate members, the thermal resistance between the holding portion 51 and the impeller portion 55 can be reduced. As a result, the amount of heat transferred from the magnet 53 to the impeller portion 55 via the holding portion 51 can be increased. Therefore, the amount of heat dissipated from the magnet 53 to the outside of the rotating electric machine 10 via the holding portion 51 and the impeller portion 55 can be increased. Consequently, the temperature of the magnet 53 can be suitably suppressed from becoming too high, and thus demagnetization of the magnet 53 can be suitably suppressed. As a result, a decrease in the driving efficiency of the rotating electric machine 10 can be suitably suppressed.

[0069] Furthermore, in this embodiment, compared to the case where the holding portion 51 and the impeller portion 55 are different and separate components, it is possible to suppress an increase in the number of parts of the rotating electric machine 10. Therefore, it is possible to suppress an increase in the manufacturing cost and manufacturing man-hours of the rotating electric machine 10.

[0070] According to this embodiment, the rotating electric machine 10 includes a cylindrical portion 20 extending axially with respect to a central axis J and positioned radially inward from the impeller portion 55, and a sealing member 95. The impeller portion 55 faces the cylindrical portion 20 with a radial gap between them, and the sealing member 95 seals the space between the impeller portion 55 and the cylindrical portion 20. Therefore, it is possible to prevent foreign matter such as moisture and dust that enters the lower side of the heat dissipation portion 60 through the intake port 63 from entering the vicinity of the rotor 50 and stator 30 through the gap between the impeller portion 55 and the cylindrical portion 20. Consequently, it is possible to prevent foreign matter from entering between the rotor 50 and stator 30 and getting caught, thereby improving the stability of the operation of the rotating electric machine 10.

[0071] According to this embodiment, when viewed from the axial direction, the intake port 63 is an annular shape surrounding the central axis J, and the heat dissipation section 60 extends radially and has a plurality of ribs 64 connecting the radially outward-facing surface of the intake port 63 and the radially inward-facing surface of the intake port 63, with each of the plurality of ribs 64 spaced apart from one another along the circumferential direction. Therefore, as described above, the surface area of ​​the heat dissipation section 60 can be increased compared to the case where the heat dissipation section 60 does not have a plurality of ribs 64. As a result, as described above, the amount of heat transferred from the heat dissipation section 60 to the airflow AF blown by the impeller section 55 can be more effectively increased, and therefore the amount of heat dissipated from the heat dissipation section 60 to the outside of the rotating electric machine 10 can be more effectively increased. Consequently, the temperature of the stator 30 can be more effectively prevented from becoming too high.

[0072] Furthermore, in this embodiment, as described above, the intake port 63 is divided into multiple intake holes 65 by multiple ribs 64. Therefore, the dimensions of each intake hole 65 can be made smaller, making it easier to make the air pressure in the internal space of the heat dissipation section 60 lower than atmospheric pressure. As a result, it is easier to make the air pressure in the internal space of the heat dissipation section 60 negative pressure, so that air can be stably drawn into the internal space of the heat dissipation section 60 through the intake port 63. Therefore, the amount of heat transferred to the air from each rib 64 can be suitably increased, and the amount of heat dissipated from the stator 30 to the outside of the rotating electric machine 10 can be suitably increased. Consequently, it is possible to suitably suppress the temperature of the stator 30 from becoming too high.

[0073] According to this embodiment, the rotating electric machine 10 is equipped with a plurality of heat transfer members 71, and the stator core 31 is provided with a plurality of holes 34a, each of which is spaced equally apart from the others along the circumferential direction, and a portion of each of the plurality of heat transfer members 71 is located in different holes 34a. Therefore, since the plurality of heat transfer members 71 can be arranged at equal intervals from each other along the circumferential direction, it is easy to reduce variations in the amount of heat transferred from the stator 30 to the heat transfer members 71 in the circumferential direction. This makes it possible to suppress the temperature of a portion of the stator 30 in the circumferential direction from becoming too high.

[0074] According to this embodiment, the heat transfer member 71 is made of a non-magnetic material. When the heat transfer member 71 is made of a magnetic material, it is necessary to place a non-magnetic member made of resin or the like between the stator core 31 and the heat transfer member 71 in order to suppress the flow of magnetic flux from the stator core 31 to the heat transfer member 71. In contrast, in this embodiment, since the heat transfer member 71 is made of a non-magnetic material, the above-mentioned non-magnetic member is unnecessary. This makes it possible to more effectively suppress an increase in the number of parts of the rotating electric machine 10. Therefore, it is possible to more effectively suppress an increase in the manufacturing cost and manufacturing man-hours of the rotating electric machine 10.

[0075] Furthermore, in this embodiment, as described above, there is no need to place a non-magnetic member between the stator core 31 and the heat transfer member 71, so it is possible to suppress an increase in thermal resistance between the stator core 31 and the heat transfer member 71. This allows for a favorable increase in the amount of heat transferred from the stator core 31 to the heat transfer member 71. Therefore, the amount of heat dissipated from the stator 30 to the outside of the rotating electric machine 10 via the heat transfer member 71 and the heat dissipation section 60 can be favorably increased. Consequently, it is possible to more favorably suppress the temperature of the stator 30 from becoming too high.

[0076] According to this embodiment, the heat transfer member 71 is a cylindrical heat pipe extending in the axial direction. Therefore, as described above, the thermal conductivity of the heat transfer member 71 can be increased compared to the case where the heat transfer member 71 is a metal columnar or cylindrical member. This allows for a more favorable increase in the amount of heat transferred from the stator 30 to the heat dissipation section 60 via the heat transfer member 71. As a result, the amount of heat dissipated from the stator 30 to the outside of the rotating electric machine 10 via the heat transfer member 71 and the heat dissipation section 60 can be more favorably increased. Consequently, the temperature of the stator 30 can be more favorably prevented from becoming too high.

[0077] According to this embodiment, the rotating electric machine 10 is connected to the rotor 50 and includes a drive transmission unit 40 that is rotatable together with the rotor 50 about a central axis J. The drive transmission unit 40 has a fixed part 48 that is located below the rotor 50 and stator 30, i.e., on the other axial side, and the fixed part 48 is fixed to a wheel 81 provided on the vehicle 80. If the fixed part 48 is located above the rotor 50 and stator 30, the heat dissipation unit 60 is housed inside the wheel 81. Therefore, when the vehicle 80 is running, it is difficult to increase the airflow velocity near the heat dissipation unit 60, and thus it is difficult to increase the amount of heat dissipated from the heat dissipation unit 60 to the outside of the rotating electric machine 10. In contrast, in this embodiment, as described above, the fixed part 48 is located below the rotor 50 and stator 30, so the heat dissipation unit 60 is exposed to the outside of the wheel 81 and tire 82 through an opening that opens into the vehicle body side of the wheel 81. This makes it possible to increase the airflow velocity near the heat dissipation section 60 when the vehicle 80 is in motion. Therefore, it is easier to increase the amount of heat dissipated from the heat dissipation section 60 to the outside of the rotating electric machine 10, thereby preventing the temperature of the stator 30 from becoming too high.

[0078] <Second Embodiment> As shown in Figure 7, the heat dissipation section 260 of the rotating electric machine 210 of this embodiment has a peripheral wall section 268. In the following description, components that are the same as those in the first embodiment described above are denoted by the same reference numerals, and their descriptions are omitted.

[0079] The rotating electric machine 210 of this embodiment includes a cylindrical portion 20, an annular support portion 26, a stator 30, a drive transmission portion 40, a rotor 50, an impeller portion 55, a heat dissipation portion 260, a sealing member 95, and a heat transfer member 71. The heat dissipation portion 260 is an annular shape surrounding the central axis J. The heat dissipation portion 260 has an annular portion 61, a top wall portion 62, a plurality of ribs 64, and a peripheral wall portion 268. The configurations of the annular portion 61, the top wall portion 62, and the plurality of ribs 64 in this embodiment are the same as those of the annular portion 61, the top wall portion 62, and the plurality of ribs 64 in the first embodiment described above.

[0080] The peripheral wall portion 268 is cylindrical in shape, extending downward from the radial outer edge of the top wall portion 62, i.e., to the other axial direction. In this embodiment, the peripheral wall portion 268 is substantially cylindrical with respect to the central axis J. The peripheral wall portion 268 is open on the lower side. The peripheral wall portion 268 is positioned radially outward from the rotor 50. Viewed radially, the lower end of the peripheral wall portion 268 overlaps with the holding portion 51, the rotor core 52, and the magnet 53, respectively. The peripheral wall portion 268 surrounds at least a part of the rotor 50 from the radial outside. In this embodiment, the peripheral wall portion 268 surrounds the upper part of the rotor 50 from the radial outside. The peripheral wall portion 268 may surround the entire rotor 50 from the radial outside. The peripheral wall portion 268 faces the rotor 50 with a radial gap between them. The other configurations of the heat dissipation section 260 in this embodiment are the same as the other configurations of the heat dissipation section 60 in the first embodiment described above. The other configurations of the rotating electric machine 210 in this embodiment are the same as the other configurations of the rotating electric machine 10 in the first embodiment described above.

[0081] The airflow AF shown by the dashed arrows in Figure 7 is the flow of air blown by each blade 58. When the impeller section 55 rotates around the central axis J, the air above the top wall section 62 flows into the impeller section 55 through the intake port 63 and then flows radially outward. The air that has flowed radially outward from the impeller section 55 flows downward between the peripheral wall section 268 and the holding section 51 and then flows out to the outside of the rotating electric machine 210. Therefore, in this embodiment, the flow velocity of the airflow AF that flows downward along the outer circumferential surface of the holding section 51 can be increased.

[0082] The second heat flow TF2, indicated by the solid arrow in Figure 7, represents the heat flow from the magnet 53 to the outside of the rotating electric machine 210 via the rotor core 52, the holding portion 51, and the impeller portion 55. Similar to the first embodiment described above, the heat transferred from the magnet 53 to the impeller portion 55 via the holding portion 51 is dissipated into the airflow AF passing through the impeller portion 55. Furthermore, in this embodiment, a portion of the heat transferred from the magnet 53 to the holding portion 51 is dissipated into the airflow AF flowing downward between the peripheral wall portion 268 and the holding portion 51. As described above, in this embodiment, the flow velocity of the airflow AF flowing downward along the outer peripheral surface of the holding portion 51 can be increased. Therefore, in this embodiment, the amount of heat dissipated from the magnet 53 to the airflow AF via the holding portion 51 can be increased.

[0083] According to this embodiment, the heat dissipation section 260 has a peripheral wall section 268 that extends downward from the radial outer edge of the top wall section 62, i.e., to the other axial direction, and the peripheral wall section 268 surrounds at least a part of the rotor 50 from the radial outside. Therefore, as described above, in this embodiment, the flow velocity of the airflow AF that flows downward along the outer peripheral surface of the holding section 51 can be increased, and the amount of heat dissipated from the magnet 53 to the airflow AF via the holding section 51 can be increased. This makes it possible to more effectively increase the amount of heat dissipated from the magnet 53 to the outside of the rotating electric machine 210. Therefore, it is possible to more effectively suppress the temperature of the magnet 53 from becoming too high, and thus more effectively suppress the demagnetization of the magnet 53. This makes it possible to effectively suppress a decrease in the driving efficiency of the rotating electric machine 210.

[0084] Furthermore, similar to the first embodiment described above, the rotating electric machine 210 of this embodiment includes a heat transfer member 71 that extends in the axial direction and connects the stator 30 and the heat dissipation section 260, with a portion of the heat transfer member 71 located in the hole 34a. Therefore, the amount of heat dissipated from the stator 30 to the outside of the rotating electric machine 210 via the heat transfer member 71 and the heat dissipation section 260 can be suitably increased. Consequently, it is possible to suppress the temperature of the stator 30 from becoming too high.

[0085] Although embodiments of the present invention have been described above, the configurations and combinations thereof in the embodiments are merely examples, and additions, omissions, substitutions, and other modifications are possible without departing from the spirit of the present invention. Furthermore, the present invention is not limited by the embodiments.

[0086] The configuration of the heat transfer members is not limited to this embodiment; for example, the heat transfer members may have other shapes, such as a roughly rectangular tube extending in the axial direction. Furthermore, some of the heat transfer members may be heat pipes, while the others may be metal columnar or cylindrical members.

[0087] The retaining part and the impeller part may be made of different materials. In this case, the impeller part may be fixed to the retaining part by bolts or the like, or it may be bonded and fixed to the retaining part by adhesive or the like.

[0088] Furthermore, this technology can take the following configurations: (1) A rotating electric machine comprising a rotor rotatable about a central axis, a stator disposed radially inward of the rotor, a heat dissipation section disposed on one axial side with respect to the rotor and the stator, and a heat transfer member extending in the axial direction and connecting the stator and the heat dissipation section, wherein the stator has a stator core surrounding the central axis, the stator core is provided with a hole recessed on the other axial side, and a part of the heat transfer member is located in the hole. (2) The rotating electric machine according to (1), comprising an impeller section disposed between the stator and the heat dissipation section and rotatable together with the rotor about the central axis, the heat dissipation section has a top wall surrounding the central axis, and the top wall is provided with an air intake that penetrates the top wall in the axial direction. (3) The rotating electric machine according to (2), wherein the heat dissipation portion has a peripheral wall portion extending from the radial outer edge of the top wall portion to the other axial direction, and the peripheral wall portion surrounds at least a part of the rotor from the radial outside. (4) The rotating electric machine according to (2) or (3), wherein the rotor has an annular rotor core surrounding the central axis, a magnet attached to the rotor core, and a holding portion surrounding the rotor core from the radial outside and holding the rotor core, and the holding portion and the impeller portion are parts of the same single member. (5) The rotating electric machine according to any one of (2) to (4), comprising a cylindrical portion extending axially with respect to the central axis and arranged radially inward from the impeller portion, and a sealing member, wherein the impeller portion faces the cylindrical portion with a radial gap between them, and the sealing member seals the space between the impeller portion and the cylindrical portion. (6) The rotating electric machine according to any one of (2) to (5), wherein, when viewed from the axial direction, the intake port is an annular shape surrounding the central axis, the heat dissipation section extends radially and has a plurality of ribs connecting the radially outward-facing surface of the intake port with the radially inward-facing surface of the intake port, and each of the plurality of ribs is spaced apart from one another along the circumferential direction.(7) The rotating electric machine according to any one of (1) to (6), comprising a plurality of heat transfer members, wherein the stator core is provided with a plurality of holes, each of the plurality of holes is provided at equal intervals from one another along the circumferential direction, and a portion of each of the plurality of heat transfer members is located in different holes. (8) The rotating electric machine according to any one of (1) to (7), wherein the heat transfer member is made of a non-magnetic material. (9) The rotating electric machine according to any one of (1) to (8), wherein the heat transfer member is a cylindrical heat pipe extending in the axial direction. (10) The rotating electric machine according to any one of (1) to (9), comprising a drive transmission unit connected to the rotor and rotatable together with the rotor about the central axis, wherein the drive transmission unit has a fixed unit located on the other axial side of the rotor and the stator, and the fixed unit is fixed to a wheel provided on a vehicle.

[0089] 10, 210... Rotating electric machine, 20... Cylindrical part, 30... Stator, 31... Stator core, 34a... Hole part, 40... Drive transmission part, 48... Fixed part, 50... Rotor, 51... Holding part, 52... Rotor core, 53... Magnet, 55... Impeller part, 60, 260... Heat dissipation part, 62... Top wall part, 63... Air intake, 64... Rib, 71... Heat transfer member, 80... Vehicle, 81... Wheel, 95... Sealing member, 268... Peripheral wall part, J... Central axis

Claims

1. A rotating electric machine comprising: a rotor rotatable about a central axis; a stator disposed radially inward of the rotor; a heat dissipation section disposed axially on one side relative to the rotor and the stator; and a heat transfer member extending axially and connecting the stator and the heat dissipation section, wherein the stator has a stator core surrounding the central axis, the stator core is provided with a hole recessed on the other axial side, and a part of the heat transfer member is located in the hole.

2. The rotating electric machine according to claim 1, comprising an impeller portion disposed between the stator and the heat dissipation portion and rotatable together with the rotor about the central axis, wherein the heat dissipation portion has a top wall portion surrounding the central axis, and the top wall portion is provided with an air intake port that penetrates the top wall portion in the axial direction.

3. The rotating electric machine according to claim 2, wherein the heat dissipation portion has a peripheral wall portion extending from the radial outer edge of the top wall portion to the other axial direction, and the peripheral wall portion surrounds at least a part of the rotor from the radial outside.

4. The rotating electric machine according to claim 2, wherein the rotor comprises an annular rotor core surrounding the central axis, a magnet attached to the rotor core, and a holding portion surrounding the rotor core from the radially outer side and holding the rotor core, and the holding portion and the impeller portion are parts of the same single member.

5. The rotating electric machine according to claim 2, comprising: a cylindrical portion extending axially with respect to the central axis and positioned radially inward from the impeller portion; and a sealing member, wherein the impeller portion faces the cylindrical portion with a radial gap between them; and the sealing member seals the space between the impeller portion and the cylindrical portion.

6. The rotating electric machine according to any one of claims 2 to 5, wherein, viewed from the axial direction, the intake port is an annular shape surrounding the central axis, the heat dissipation section extends radially and has a plurality of ribs connecting the radially outward-facing surface of the intake port with the radially inward-facing surface of the intake port, and each of the plurality of ribs is spaced apart from one another along the circumferential direction.

7. The rotating electric machine according to any one of claims 1 to 5, comprising a plurality of heat transfer members, wherein the stator core is provided with a plurality of holes, each of the plurality of holes is provided at equal intervals from one another along the circumferential direction, and a portion of each of the plurality of heat transfer members is located in different holes.

8. The rotating electric machine according to any one of claims 1 to 5, wherein the heat transfer member is made of a non-magnetic material.

9. The rotating electric machine according to any one of claims 1 to 5, wherein the heat transfer member is a cylindrical heat pipe extending in the axial direction.

10. A rotating electric machine according to any one of claims 1 to 5, comprising a drive transmission unit connected to the rotor and rotatable together with the rotor about the central axis, wherein the drive transmission unit has a fixed portion positioned on the other axial side of the rotor and the stator, and the fixed portion is fixed to a wheel provided on the vehicle.

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