motor

Abstract

To provide a motor which allows improvement in heat dissipation of a stator.SOLUTION: A motor 10 comprises: a rotor 20 which is rotatable around a central axis; a stator 30 which is disposed outside in a radial direction of the rotor so as to face the rotor with a gap provided in the radial direction; a cylindrical housing 40 which surrounds the stator from the outside in the radial direction; a heat dissipation part 50 which is disposed outside in the radial direction of the housing so as to face the housing with a gap provided in the radial direction; and a heat transfer part 80 at least part of which is located between the housing and the heat dissipation part. The heat transfer part is in contact with the heat dissipation part and comes into contact with the stator in a direct manner or via the housing.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a motor.

Background Art

[0002] Motors that cool the stator using a cooling medium are known. For example, Patent Document 1 describes a motor cooling device that circulates a refrigerant through a cooling refrigerant passage provided in the stator to cool the stator.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In motors using a cooling medium, there has been a demand for further improvement in heat dissipation performance to dissipate the heat generated in the stator to the outside of the motor. [[ID=FF]]

[0005] One aspect of the present invention is, in view of the above circumstances, to provide a motor capable of improving the heat dissipation performance of the stator as one of the objectives.

Means for Solving the Problems

[0006] One aspect of the motor of the present invention includes a rotor rotatable about a central axis, a stator disposed radially outside the rotor, a cylindrical housing surrounding the stator from the radially outside, a heat radiating portion disposed radially outside the housing and facing the housing with a gap in the radial direction, and a heat transfer portion at least partially located between the housing and the heat radiating portion. The heat transfer portion contacts the heat radiating portion and contacts the stator directly or via the housing.

Effects of the Invention

[0007] According to one aspect of the present invention, the heat dissipation performance of the stator in a motor can be improved. [Brief explanation of the drawing]

[0008] [Figure 1] Figure 1 is a perspective view showing the motor of the first embodiment. [Figure 2] Figure 2 is a cross-sectional view showing the motor of the first embodiment. [Figure 3] Figure 3 is a perspective view showing a part of the motor of the first embodiment. [Figure 4] Figure 4 is a partial cross-sectional perspective view showing a portion of the heat dissipation section of the first embodiment. [Figure 5] Figure 5 is a cross-sectional view showing a part of the motor of the first embodiment, and is a cross-sectional view of VV in Figure 2. [Figure 6] Figure 6 is a cross-sectional view showing a part of the motor of the first embodiment. [Figure 7] Figure 7 is a cross-sectional view showing the heat dissipation unit mounting process of the first embodiment. [Figure 8] Figure 8 is a cross-sectional view showing a part of the motor of the second embodiment. [Figure 9] Figure 9 is a perspective view showing a part of the motor of the second embodiment. [Figure 10] Figure 10 is a perspective view showing the heat transfer section of the second embodiment. [Figure 11] Figure 11 is a cross-sectional view showing the heat transfer section mounting process of the second embodiment. [Figure 12] Figure 12 is a cross-sectional view showing a part of the motor of the third embodiment. [Figure 13] Figure 13 is a partial cross-sectional perspective view showing a portion of the heat dissipation section of the third embodiment. [Modes for carrying out the invention]

[0009] In the following description, the Z-axis will be shown in the figures as appropriate. The Z-axis indicates the direction in which the central axis J of the motor in the embodiment described below extends. The central axis J shown in each figure 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, will be called the "axial direction". The side of the axial direction in which the Z-axis arrow points (+Z side) will be called the "other axial side" or "upper side". The side of the axial direction opposite to the side in which the Z-axis arrow points (-Z side) will be called the "one axial side" or "lower side". The radial direction centered on the central axis J will be simply called the "radial direction". The circumferential direction centered on the central axis J will be simply called the "circumferential direction". Note that the upper side and lower side are merely names used to describe the arrangement of the parts, etc., and the actual arrangement may be other than the arrangement indicated by these names.

[0010] The circumferential direction is indicated by the arrow θ in each diagram. The side of the circumferential direction in which the arrow θ points 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 is called the "other side of the circumferential direction." The one side of the circumferential direction (+θ side) is the side that moves clockwise around the central axis J when viewed from above (+Z side). The other side of the circumferential direction (-θ side) is the side that moves counterclockwise around the central axis J when viewed from above.

[0011] Furthermore, in the following explanation, "contact" and "direct contact" mean that two components are in contact without any intervening material between them. Also, "contact via A" means that two components are in thermal contact with A in between. In this case, the two components that are in contact via A are in direct contact with A, but they are not in direct contact with each other.

[0012] <First Embodiment> The motor 10 of this embodiment shown in Figure 1 is an electric motor that is attached to an unmanned aerial vehicle such as an unmanned aircraft. As shown in Figure 2, the motor 10 comprises a rotor 20, a stator 30, a housing 40, a first bearing 61, a second bearing 62, a first sealing member 63, a second sealing member 64, a heat dissipation section 50, a heat transfer section 80, and a cooling medium C.

[0013] The housing 40 houses therein the rotor 20, the stator 30, the first bearing 61, the second bearing 62, the first sealing member 63, the second sealing member 64, and a part of the cooling medium C. The housing 40 includes a cylindrical member 41, an inner lid member 42, an outer lid member 43, and a lower ring member 48.

[0014] The cylindrical member 41 is cylindrical and extends in the axial direction about the central axis J. The cylindrical member 41 is made of, for example, a non-magnetic metal. The cylindrical member 41 is made of a metal such as aluminum. The cylindrical member 41 has a cylindrical portion 41a, a bottom portion 41b, a second bearing holding portion 41c, a second support portion 41d, and a second sealing member holding portion 41e.

[0015] As shown in FIG. 2, the cylindrical portion 41a is cylindrical and extends in the axial direction about the central axis J. The cylindrical portion 41a surrounds the rotor 20, the stator 30, the first sealing member 63, and the second sealing member 64 from the radially outer side. The cylindrical portion 41a is disposed radially inside the heat radiating portion 50. The upper end portion of the cylindrical portion 41a is located above the stator 30. An opening 41g that opens upward is provided at the upper end portion of the cylindrical portion 41a. As viewed in the axial direction, the opening 41g is circular about the central axis J. The lower end portion of the cylindrical portion 41a is located below the stator 30. A plurality of through holes 41k and a plurality of connection holes 41i are provided in the cylindrical portion 41a.

[0016] As shown in FIG. 2, the through hole 41k is a hole that penetrates the cylindrical portion 41a in the radial direction. The through hole 41k is provided in the upper portion of the cylindrical portion 41a. As viewed in the radial direction, the through hole 41k is substantially rectangular and extends in the circumferential direction. As shown in FIG. 3, the through holes 41k are provided at intervals along the circumferential direction. Although not shown, in the present embodiment, 23 through holes 41k are provided.

[0017] The connection holes 41i are holes that penetrate the cylindrical portion 41a in the radial direction. The connection holes 41i are provided in the lower part of the cylindrical portion 41a. In this embodiment, when viewed radially, the connection holes 41i are substantially elliptical in shape and extend in the circumferential direction. The shape of the connection holes 41i may be other shapes such as circular. As shown in Figure 2, the connection holes 41i are located below the stator 30. Each connection hole 41i is provided at intervals along the circumferential direction. Although not shown in the figure, in this embodiment, seven connection holes 41i are provided.

[0018] The bottom portion 41b is an annular plate shape centered on the central axis J. The plate surface of the bottom portion 41b faces axially. The radially outer end of the bottom portion 41b is connected to the lower end of the cylindrical portion 41a.

[0019] The second bearing retaining portion 41c is cylindrical in shape, projecting axially from the central axis J. The second bearing retaining portion 41c surrounds the second bearing 62 and the lower portion of the shaft 25. The outer circumferential surface of the second bearing retaining portion 41c connects to the radially inward end of the bottom portion 41b. The second bearing 62 is held in the inner circumferential surface of the second bearing retaining portion 41c. The inner circumferential surface of the second bearing retaining portion 41c contacts the O-rings 73 and 74 held in the outer circumferential surface of the second bearing 62. A groove is provided in the portion of the inner circumferential surface of the second bearing retaining portion 41c below the second bearing 62, and the radially outer edge of the retaining ring 75, which will be described later, is fitted into the groove.

[0020] The second support portion 41d is an annular plate shape centered on the central axis J. The plate surface of the second support portion 41d faces axially. The radially outer end of the second support portion 41d is connected to the upper end of the second bearing retaining portion 41c. The upper-facing surface of the second support portion 41d supports the lower-facing surface of the second sealing member 64. The lower-facing surface of the second support portion 41d supports the upper-facing surface of the outer ring of the second bearing 62. These arrangements determine the positions of the second sealing member 64 and the second bearing 62 relative to the housing 40 in the axial direction. The second support portion 41d has a first opening 41h. Viewed in the axial direction, the first opening 41h is substantially circular in shape centered on the central axis J. The lower portion of the shaft 25 passes through the first opening 41h.

[0021] The second sealing member holder portion 41e is cylindrical in shape, projecting axially from the central axis J. The lower end of the second sealing member holder portion 41e is connected to the upper surface of the second support portion 41d. The second sealing member 64 is held on the inner circumferential surface of the second sealing member holder portion 41e. A groove is provided on the inner circumferential surface of the second sealing member holder portion 41e above the second sealing member 64, and a retaining ring 66, described later, is fitted into the groove.

[0022] As shown in Figures 2 and 3, the inner lid member 42 is substantially annular in shape with respect to the central axis J. The inner lid member 42 is fixed to the opening 41g of the cylindrical member 41. As shown in Figure 2, the inner lid member 42 is positioned above the stator 30. The inner lid member 42 is made of, for example, a non-magnetic metal. The inner lid member 42 is made of a metal such as aluminum. The inner lid member 42 has a first annular portion 42a, a fitting portion 42b, a plurality of inner lid connecting portions 42c, a first bearing holding portion 42d, a first sealing member holding portion 42e, and a first support portion 42f.

[0023] The first annular portion 42a is an annular plate shape centered on the central axis J. The plate surface of the first annular portion 42a is oriented in the axial direction. The radially outer end of the downward-facing surface of the first annular portion 42a is in contact with the upper end of the cylindrical portion 41a.

[0024] The fitting portion 42b is an annular shape that protrudes axially with respect to the central axis J. The fitting portion 42b protrudes downward from the radially outer portion of the first annular portion 42a. The outer circumferential surface of the fitting portion 42b is fitted into the inner circumferential surface of the cylindrical portion 41a. As a result, the inner lid member 42 is fixed to the cylindrical member 41.

[0025] As shown in Figure 3, each of the multiple inner lid connecting portions 42c connects the first annular portion 42a and the first bearing holding portion 42d. Each of the multiple inner lid connecting portions 42c extends radially from each other with respect to the central axis J. The inner lid connecting portions 42c extend radially inward from the radially inward end of the first annular portion 42a. Viewed in the axial direction, the inner lid connecting portion 42c is substantially rectangular in shape. Each of the multiple inner lid connecting portions 42c is provided at intervals along the circumferential direction. In this embodiment, 12 inner lid connecting portions 42c are provided. Ventilation holes 42g are provided between adjacent inner lid connecting portions 42c in the circumferential direction.

[0026] The ventilation holes 42g are substantially trapezoidal when viewed in the axial direction. The ventilation holes 42g are holes that penetrate the inner lid member 42 in the axial direction. Multiple ventilation holes 42g are provided at intervals along the circumferential direction. In this embodiment, twelve ventilation holes 42g are provided. The inside of the cylindrical member 41 and the first space 15, which will be described later, are connected through the ventilation holes 42g.

[0027] As shown in Figure 2, the first bearing retainer 42d is cylindrical in shape, projecting axially from the central axis J. The first bearing retainer 42d surrounds the upper portion of the shaft 25 and the first bearing 61. The lower end of the first bearing retainer 42d connects to the radially inward end of the inner cover connecting portion 42c. The first bearing 61 is held on the inner circumferential surface of the first bearing retainer 42d. The inner circumferential surface of the first bearing retainer 42d contacts the O-rings 71 and 72 held on the outer circumferential surface of the first bearing 61. Multiple threaded portions 42h are provided on the upper-facing surface of the first bearing retainer 42d.

[0028] Each of the multiple threaded portions 42h is a female thread. Multiple threaded portions 42h are provided at intervals along the circumferential direction. In this embodiment, four threaded portions 42h are provided.

[0029] As shown in Figure 1, the first sealing member holder portion 42e is cylindrical in shape, projecting axially from the central axis J. The upper end of the first sealing member holder portion 42e is connected to the lower end of the first bearing holder portion 42d. The first sealing member 63 is held on the inner circumferential surface of the first sealing member holder portion 42e. A groove is provided in the portion of the inner circumferential surface of the first sealing member holder portion 42e below the first sealing member 63, and a retaining ring 65, which will be described later, is fitted into the groove.

[0030] The first support portion 42f is an annular plate shape centered on the central axis J. The plate surface of the first support portion 42f faces axially. The radially outer end of the first support portion 42f is connected to the upper end of the first sealing member holding portion 42e. The downward-facing surface of the first support portion 42f supports the upward-facing surface of the first sealing member 63. The upward-facing surface of the first support portion 42f supports the downward-facing surface of the outer ring of the first bearing 61. These arrangements determine the positions of the first sealing member 63 and the first bearing 61 relative to the housing 40 in the axial direction. The first support portion 42f has a second opening 42i that opens in the axial direction. Viewed in the axial direction, the second opening 42i is circular in shape centered on the central axis J. The upper portion of the shaft 25 passes through the second opening 42i.

[0031] As shown in Figures 1 and 2, the outer cover member 43 is substantially cylindrical with respect to the central axis J. The outer cover member 43 is positioned above the first annular portion 42a and the inner cover connecting portion 42c. The outer cover member 43 is positioned radially outward of the first bearing holding portion 42d. The radially outward end of the outer cover member 43 is fixed to the upper end of the heat dissipation portion 50. The outer cover member 43 is made of, for example, a non-magnetic metal. The outer cover member 43 is made of a metal such as aluminum. The outer cover member 43 has a second annular portion 43a, a second cylindrical portion 43b, a third annular portion 43c, an O-ring holding portion 43d, and a first protrusion 43e.

[0032] As shown in Figure 2, the second annular portion 43a is an annular plate shape centered on the central axis J. The plate surface of the second annular portion 43a faces axially. The downward-facing surface of the second annular portion 43a is joined and fixed to the upper cover 57, which will be described later. The downward-facing surface of the second annular portion 43a may be fixed to the upper cover 57 with an adhesive such as a urethane adhesive or a silicone adhesive, or it may be bonded and fixed with an adhesive such as a melamine resin adhesive or a phenolic resin adhesive.

[0033] As shown in Figure 1, the first projection 43e is plate-shaped and protrudes downward from the outer edge of the second annular portion 43a. The plate surface of the first projection 43e faces radially. The plate surface of the first projection 43e is arc-shaped with respect to the central axis J. Multiple first projections 43e are provided at intervals along the circumferential direction. In this embodiment, 45 first projections 43e are provided. Each first projection 43e is positioned between adjacent upper covers 57 in the circumferential direction. The radially inward surface of each first projection 43e is fitted to the outer circumferential surface of the inner wall portion 52b of the heat dissipation portion 50, which will be described later. The two circumferentially facing surfaces of each first projection 43e are fitted to the circumferentially facing surfaces of the upper cover 57.

[0034] As shown in Figure 2, the second cylindrical portion 43b is cylindrical in shape, extending axially with respect to the central axis J. The second cylindrical portion 43b surrounds the first bearing 61 and the upper portion of the shaft 25. The upper end of the second cylindrical portion 43b is connected to the radially inner end of the second annular portion 43a. The outer circumferential surface of the second cylindrical portion 43b is fitted to the inner circumferential surface of the inner wall portion 52b of the heat dissipation portion 50, which will be described later. The outer cover member 43 and the heat dissipation portion 50 are fixed to each other by fitting the first protrusion 43e and the second cylindrical portion 43b with the inner wall portion 52b or the upper cover 57.

[0035] The third annular portion 43c is an annular plate shape centered on the central axis J. The radially outer end of the third annular portion 43c is connected to the lower end of the second cylindrical portion 43b. The third annular portion 43c is located lower as it moves radially inward. The third annular portion 43c is positioned above the inner lid connection portion 42c, with a gap between them. The space between the third annular portion 43c and the inner lid connection portion 42c is the first space 15. The first space 15 is the space through which the vaporized cooling medium C, which is gas CG, passes when it moves from the inside of the cylindrical member 41 to the heat dissipation portion 50.

[0036] The O-ring holder portion 43d is an annular shape surrounding the central axis J. The radially outer end of the O-ring holder portion 43d connects to the radially inner end of the third annular portion 43c. The lower end of the O-ring holder portion 43d contacts the inner cover member 42. This determines the axial positions of the outer cover member 43 and the inner cover member 42. A groove is provided on the inner circumferential surface of the O-ring holder portion 43d, into which the O-ring 76, described later, is fitted.

[0037] As shown in Figure 2, the lower ring member 48 is an annular shape surrounding the central axis J. The lower ring member 48 surrounds the lower end of the cylindrical member 41. The lower ring member 48 is positioned below the heat dissipation section 50. The lower ring member 48 is fixed to the outer circumferential surface of the lower end of the cylindrical section 41a. The lower ring member 48 is made of, for example, a non-magnetic metal. The lower ring member 48 is made of a metal such as aluminum. The lower ring member 48 has a base portion 48a, a second projection portion 48b, and a third projection portion 48c.

[0038] The base portion 48a is annular in shape with a central axis J at its center. The inner circumferential surface of the base portion 48a is fitted onto the outer circumferential surface of the lower end of the cylindrical portion 41a. This fixes the lower ring member 48 and the cylindrical member 41 to each other. A groove is provided on the inner circumferential surface of the base portion 48a, into which an O-ring 70, described later, is fitted. The upper-facing surface of the base portion 48a is joined to the lower cover 58. This fixes the lower ring member 48 and the heat dissipation portion 50 to each other.

[0039] The second projection 48b protrudes upward from the radially inward end of the base 48a. The second projection 48b is annular in shape with respect to the central axis J. The outer circumferential surface of the second projection 48b is fitted with the inner circumferential surface of the inner wall portion 52b of the heat dissipation portion 50, which will be described later. This fixes the lower ring member 48 and the heat dissipation portion 50 to each other.

[0040] As shown in Figure 1, the third projection 48c is plate-shaped and protrudes upward from the base 48a. The plate surface of the third projection 48c faces radially. The plate surface of the third projection 48c is arc-shaped with respect to the central axis J. Multiple third projections 48c are provided at intervals along the circumferential direction. In this embodiment, 45 third projections 48c are provided. In this embodiment, each third projection 48c is provided between adjacent lower covers 58 in the circumferential direction. The radially inward-facing surface of each third projection 48c is fitted to the outer circumferential surface of the inner wall portion 52b of the heat dissipation section 50, which will be described later. The two circumferential-facing surfaces of each third projection 48c are fitted to the circumferential-facing surfaces of the lower cover 58. In this way, the lower ring member 48 and the heat dissipation section 50 are fixed to each other.

[0041] The rotor 20 is rotatable about a central axis J. As shown in Figure 2, the rotor 20 includes a rotor core 21, a plurality of magnets 22, a connecting member 23, and a shaft 25.

[0042] The rotor core 21 is cylindrical in shape, extending axially around a central axis J. The rotor core 21 is positioned radially inward of the stator 30. Each of the multiple magnets 22 is fixed to the outer circumferential surface of the rotor core 21. Each of the multiple magnets 22 is plate-shaped, extending axially. Each of the multiple magnets 22 faces the stator 30 at a radial distance. Each of the multiple magnets 22 is provided at intervals along the outer circumferential surface of the rotor core 21.

[0043] As shown in Figure 2, the connecting member 23 connects the rotor core 21 and the shaft 25. The connecting member 23 has a rotor core holding portion 23a, a rotor core support portion 23b, and a shaft holding portion 23c.

[0044] The rotor core holder portion 23a is cylindrical in shape, extending axially around the central axis J. The rotor core 21 is fixed to the outer circumferential surface of the rotor core holder portion 23a.

[0045] The rotor core support portion 23b is an annular plate shape centered on the central axis J. The plate surface of the rotor core support portion 23b faces axially. The radially inner end of the rotor core support portion 23b is connected to the upper end of the rotor core holding portion 23a. The downward-facing surface of the rotor core support portion 23b is in contact with the upward-facing surface of the rotor core 21. This determines the axial position of the rotor core 21 and the shaft 25.

[0046] The shaft holder portion 23c is an annular shape surrounding the central axis J. The outer circumferential surface of the shaft holder portion 23c is connected to the inner circumferential surface of the rotor core holder portion 23a. The shaft 25 is fixed to the inner circumferential surface of the shaft holder portion 23c.

[0047] As shown in Figure 2, the shaft 25 is cylindrical, extending axially around a central axis J. In the axial direction, the central portion of the shaft 25 is housed inside the cylindrical member 41 and fixed to the rotor core 21 via the connecting member 23. The upper portion of the shaft 25 protrudes above the housing 40 through the second opening 42i. The upper portion of the shaft 25 is supported by the first bearing 61. The portion of the outer circumferential surface of the shaft 25 below the first bearing 61 contacts the inner circumferential surface of the first sealing member 63. The lower end of the shaft 25 protrudes below the housing 40 through the first opening 41h. The lower portion of the shaft 25 is supported by the second bearing 62. The portion of the outer circumferential surface of the shaft 25 above the second bearing 62 contacts the inner circumferential surface of the second sealing member 64.

[0048] In this embodiment, the first bearing 61 and the second bearing 62 are ball bearings. The first bearing 61 and the second bearing 62 may be rolling bearings other than ball bearings, or they may be sliding bearings. The first bearing 61 rotatably supports the upper portion of the shaft 25. The second bearing 62 rotatably supports the lower portion of the shaft 25. These allow the rotor 20 to rotate about the central axis J.

[0049] As shown in Figure 2, the stator 30 is positioned radially outward of the rotor 20. The stator 30 is annular in shape and surrounds the rotor 20. The stator 30 faces the rotor 20 with a radial gap between them. The stator 30 is fixed to the inner circumferential surface of the cylindrical portion 41a. The stator 30 has a stator core 31 and a plurality of coils 32.

[0050] The stator core 31 is an annular shape that surrounds the rotor core 21. The outer circumferential surface of the stator core 31 is fixed to the inner circumferential surface of the cylindrical portion 41a. In the axial direction, the upper end of the stator core 31 is located below the multiple through holes 41k. In the axial direction, the lower end of the stator core 31 is located above the multiple connection holes 41i.

[0051] Each of the coils 32 is mounted on the stator core 31. The coils 32 are arranged at intervals from each other along the circumferential direction. Each of the coils 32 is electrically connected to a control device (not shown). Current is supplied to each of the coils 32 from an external power source (not shown) via the control device. Joule heat is generated in the coils 32 due to the supply of current. A portion of each of the coils 32 is in contact with the stator core 31.

[0052] In this embodiment, the first sealing member 63 and the second sealing member 64 are lip seals having lip portions on their radially inward sides. As shown in Figure 2, the lip portion of the first sealing member 63 contacts the outer circumferential surface of the upper portion of the shaft 25. As a result, the first sealing member 63 seals the space between the shaft 25 and the inner lid member 42. The lip portion of the second sealing member 64 contacts the outer circumferential surface of the lower portion of the shaft 25. As a result, the second sealing member 64 seals the space between the shaft 25 and the cylindrical member 41.

[0053] In this embodiment, the retaining rings 65, 66, and 75 are, for example, C-shaped retaining rings. As described above, the radial outer edge of retaining ring 65 is fitted into a groove provided on the inner circumferential surface of the first sealing member holding portion 42e. Retaining ring 65 supports the first sealing member 63 from below. The radial outer edge of retaining ring 66 is fitted into a groove provided on the inner circumferential surface of the second sealing member holding portion 41e. Retaining ring 66 supports the second sealing member 64 from above. The radial outer edge of retaining ring 75 is fitted into a groove provided on the inner circumferential surface of the second bearing holding portion 41c. Retaining ring 75 supports the second bearing 62 from below.

[0054] As described above, O-ring 70 is fitted into a groove provided on the inner circumferential surface of the base portion 48a. O-ring 70 seals the space between the lower ring member 48 and the cylindrical member 41. O-rings 71 and 72 are each fitted into grooves provided on the outer circumferential surface of the outer ring of the first bearing 61. O-rings 71 and 72 seal the space between the first bearing 61 and the inner cover member 42. O-rings 73 and 74 are each fitted into grooves provided on the outer circumferential surface of the outer ring of the second bearing 62. O-rings 73 and 74 seal the space between the second bearing 62 and the cylindrical member 41. O-ring 76 is fitted into a groove provided on the inner circumferential surface of the O-ring holding portion 43d. O-ring 76 seals the space between the inner cover member 42 and the outer cover member 43.

[0055] As shown in Figures 1 and 2, the pressing member 67 is fixed to the inner cover member 42. The pressing member 67 is fixed with bolts 69 to the surface facing the upper side of the first bearing holding portion 42d. As shown in Figure 2, the pressing member 67 is a substantially annular plate shape with a central axis J at its center. The plate surface of the pressing member 67 faces axially, and the pressing member 67 is provided with multiple holes that penetrate in the axial direction. The multiple holes are spaced apart along the circumferential direction. In this embodiment, eight holes are provided. A bolt 69, which is tightened into a threaded portion 42h, is passed through each hole. In this way, the pressing member 67 is fixed to the inner cover member 42.

[0056] The washer 68 is positioned axially between the first bearing 61 and the pressing member 67. The washer 68 surrounds the shaft 25. In this embodiment, the washer 68 is a corrugated washer. The washer 68 contacts the upper surface of the first bearing 61 and the lower surface of the pressing member 67. This determines the axial position of the first bearing 61.

[0057] As shown in Figure 2, the heat dissipation section 50 is positioned radially outward from the housing 40. The heat dissipation section 50 faces the cylindrical member 41 of the housing 40 with a radial gap in between. When the motor 10 is driven, the heat dissipation section 50 dissipates the heat generated in the stator 30 to the outside of the motor 10. The heat dissipation section 50 includes a heat dissipation member 51, an upper cover 57, and a lower cover 58.

[0058] The heat dissipation member 51 surrounds the housing 40 from the radially outer side. The heat dissipation member 51 is made of, for example, a non-magnetic metal. The heat dissipation member 51 is made of a metal such as aluminum. The heat dissipation member 51 has a fourth cylindrical portion 52 and a plurality of protruding heat dissipation portions 53.

[0059] As shown in Figures 2 and 4, the fourth cylindrical portion 52 is cylindrical in shape, extending axially with respect to the central axis J. The fourth cylindrical portion 52 is located radially outward of the housing 40. As shown in Figure 2, in the axial direction, the upper end of the fourth cylindrical portion 52 is located above the first space 15. The lower end of the fourth cylindrical portion 52 is located below the connection hole 41i. The fourth cylindrical portion 52 has a plurality of heat dissipation openings 52a and a plurality of inner wall portions 52b.

[0060] As shown in Figure 4, each of the multiple heat dissipation openings 52a is a hole that penetrates the fourth cylindrical portion 52 radially. Viewed radially, each heat dissipation opening 52a is substantially rectangular in shape and extends in the axial direction. Each heat dissipation opening 52a extends from the upper end to the lower end of the fourth cylindrical portion 52. The multiple heat dissipation openings 52a are provided at equal intervals from each other along the circumferential direction. In this embodiment, 45 heat dissipation openings 52a are provided.

[0061] The inner wall portion 52b is the portion of the fourth cylindrical portion 52 between adjacent heat dissipation openings 52a in the circumferential direction. Multiple inner wall portions 52b are provided at intervals along the circumferential direction. In this embodiment, 45 inner wall portions 52b are provided. Viewed radially, the inner wall portion 52b is substantially rectangular in shape and extends in the axial direction. The upper end of the inner wall portion 52b is the upper end of the fourth cylindrical portion 52. The lower end of the inner wall portion 52b is the lower end of the fourth cylindrical portion 52. In this embodiment, the heat dissipation opening 52a is provided along the entire axial length of the fourth cylindrical portion 52. Therefore, the fourth cylindrical portion 52 is divided into multiple arc-shaped portions (inner wall portions 52b) by the multiple heat dissipation openings 52a. In this specification, the heat dissipation opening 52a and the inner wall portions 52b arranged circumferentially on either side of the heat dissipation opening 52a are described as a single fourth cylindrical portion 52.

[0062] As described above, the outer surface of the second cylindrical portion 43b is fitted onto the inner surface of the upper part of the inner wall portion 52b. As shown in Figure 1, the radially inward-facing surfaces of each of the multiple first protrusions 43e are fitted onto the outer surface of the upper part of the inner wall portion 52b. In this way, the heat dissipation portion 50 and the outer cover member 43 are fixed to each other.

[0063] As shown in Figure 2, the outer surface of the second projection 48b is fitted onto the inner surface of the lower part of the inner wall 52b. As shown in Figure 1, the radially inward-facing surfaces of each of the multiple third projections 48c are fitted onto the outer surface of the lower part of the inner wall 52b. In this way, the heat dissipation section 50 and the lower ring member 48 are fixed to each other.

[0064] As shown in Figure 2, the axial central portion of the inner wall 52b faces the cylindrical member 41 with a radial gap between them. In other words, at least a portion of the heat dissipation section 50 faces the housing 40 with a radial gap between them. In the following description, the space between the cylindrical member 41 and the fourth cylindrical section 52 will be referred to as the second space 16.

[0065] As shown in Figure 5, the multiple protruding heat dissipation sections 53 extend radially outward from the central axis J. The multiple protruding heat dissipation sections 53 are arranged at equal intervals from each other along the circumferential direction. In this embodiment, 45 protruding heat dissipation sections 53 are provided. Viewed in the axial direction, the multiple protruding heat dissipation sections 53 are arranged in a heat dissipation fin shape. That is, the heat dissipation section 50 is in the shape of a heat dissipation fin. The protruding heat dissipation section 53 is a hollow, approximately rectangular parallelepiped. Viewed in the axial direction, the protruding heat dissipation section 53 is rectangular. The radial dimension of the protruding heat dissipation section 53 is larger than the circumferential dimension. As shown in Figure 4, in the axial direction, the position of the upper end of the protruding heat dissipation section 53 is the same as the position of the upper end of the fourth cylindrical section 52. In the axial direction, the position of the lower end of the protruding heat dissipation section 53 is the same as the position of the lower end of the fourth cylindrical section 52. The upper end of the protruding heat dissipation section 53 opens upward. The lower end of the protruding heat dissipation section 53 opens downwards.

[0066] As described above, according to this embodiment, since the heat dissipation section 50 is in the shape of heat dissipation fins, the surface area of ​​the outer surface of the heat dissipation section 50 can be increased. Therefore, the heat from the stator 30 that has been transferred to the heat dissipation section 50 can be more effectively dissipated to the outside of the motor 10. Thus, the heat dissipation performance of the stator 30 can be improved.

[0067] As described above, each of the multiple protruding heat dissipation sections 53 is hollow. Therefore, the surface area of ​​the inner surface of the protruding heat dissipation section 53 can be increased. As shown in Figure 2, the upper part of the interior of each of the multiple protruding heat dissipation sections 53 is connected to the interior of the cylindrical member 41 via the ventilation holes 42g, the first space 15, and the heat dissipation opening 52a. The lower part of the interior of each of the multiple protruding heat dissipation sections 53 is connected to the interior of the cylindrical member 41 via the connection holes 41i and the heat dissipation opening 52a. The central part of the interior of each of the multiple protruding heat dissipation sections 53 in the axial direction is connected to the second space 16 via the heat dissipation opening 52a. As shown in Figure 5, each of the multiple protruding heat dissipation sections 53 has a first wall section 53a, a second wall section 53b, and a third wall section 53c.

[0068] The first wall portion 53a extends radially outward from the other circumferential side (-θ side) end of the inner wall portion 52b. The second wall portion 53b extends radially outward from the one circumferential side (+θ side) end of the inner wall portion 52b. The third wall portion 53c connects the radially outward end of the first wall portion 53a to the radially outward end of the second wall portion 53b, which is located adjacent to the other circumferential side of the first wall portion 53a. Thus, the heat dissipation portion 50 has a plurality of inner wall portions 52b that connect the radially inward ends of adjacent protruding heat dissipation portions 53.

[0069] As shown in Figures 1 and 2, the top cover 57 is fitted and secured to the upper end of the protruding heat dissipation section 53. The top cover 57 closes the upper opening of the protruding heat dissipation section 53. The bottom cover 58 is fitted and secured to the lower end of the protruding heat dissipation section 53. The bottom cover 58 closes the lower opening of the protruding heat dissipation section 53.

[0070] The cooling medium C transfers the heat generated in the stator 30 to the heat dissipation section 50. As shown in Figure 2, the cooling medium C is housed inside the housing 40, inside the heat dissipation section 50, and in the second space 16. The cooling medium C is a liquid substance at room temperature. Room temperature is, for example, 5°C or higher and 35°C or lower, but is not limited to this temperature range depending on the type of cooling medium. In the following description, the cooling medium C in liquid state will be called the coolant CL, and the cooling medium C in gaseous state will be called the gas CG. In this embodiment, the cooling medium C is insulating. Therefore, it is not necessary to apply insulating treatment to each part of the motor 10 that comes into contact with the cooling medium C. Thus, the manufacturing man-hours of the motor 10 can be reduced. The cooling medium C is, for example, a fluorine-based compound. The fluorine-based compound is not particularly limited as long as it is a compound containing fluorine atoms. A lubricant is mixed into the cooling medium C. In this embodiment, the lubricant mixed into the cooling medium C is a lubricant used for ball bearings.

[0071] As shown in Figure 6, the cooling medium C circulates between the inside of the housing 40, the inside of the protruding heat dissipation section 53, and the second space 16, changing its state between liquid and gaseous. The cooling liquid CL is contained in the lower part of the inside of the cylindrical member 41, the lower part of the inside of the protruding heat dissipation section 53, and the second space 16. The gas CG is contained in the upper part of the inside of the cylindrical member 41, the first space 15, and the upper part of the inside of the protruding heat dissipation section 53.

[0072] The liquid level CLS of the coolant CL is located above the coil 32. Therefore, the coolant CL is in contact with the stator 30. In other words, the cooling medium C is in contact with the stator 30. As described above, since the coolant CL is in liquid form, it can come into contact with the stator core 31 and the coil 32 without any gaps. Therefore, the coolant CL can effectively absorb the heat generated in the stator 30.

[0073] Inside the protruding heat dissipation section 53, the coolant CL is in contact with the lower portion of the inner surface of the protruding heat dissipation section 53. In other words, the cooling medium C is in contact with the heat dissipation section 50. The upper portion of the protruding heat dissipation section 53 is located above the liquid level CLS of the cooling medium C. Therefore, the portion of the protruding heat dissipation section 53 located above the liquid level CLS of the cooling medium C is connected to the inside of the housing 40 via the heat dissipation opening 52a.

[0074] Therefore, according to this embodiment, when the temperature of the stator 30 rises due to Joule heating generated in the coil 32, the liquid coolant CL in contact with the stator 30 absorbs heat from the stator 30, and a portion of the coolant CL vaporizes to become gas CG. At this time, the stator 30 can be suitably cooled by the heat of vaporization when the coolant CL vaporizes. Also, as shown in Figure 6, the gas CG moves upward inside the cylindrical member 41 and can flow into the part of the protruding heat dissipation section 53 above the liquid level CLS through the vent hole 42g, the first space 15, and the heat dissipation opening 52a (arrow R1). The gas CG that has flowed into the protruding heat dissipation section 53 condenses upon contact with the inner surface of the protruding heat dissipation section 53 and is cooled, becoming coolant CL. At this time, the heat of the gas CG is transferred to the protruding heat dissipation section 53. In addition, since the protruding heat dissipation section 53 is hollow, the surface area of ​​the inner surface of the protruding heat dissipation section 53 can be increased. Therefore, the surface area in contact between the gas CG and the protruding heat dissipation section 53 can be increased, allowing the heat from the gas CG to be suitably transferred to the protruding heat dissipation section 53. Furthermore, since the heat dissipation section 50 is fin-shaped, the surface area of ​​the outer surface of the heat dissipation section 50 can be increased. Consequently, the heat transferred to the heat dissipation section 50 can be suitably dissipated to the outside of the motor 10. In other words, the cooling medium C allows the heat generated in the stator 30 to be suitably dissipated to the outside of the motor 10.

[0075] The liquefied coolant CL in the protruding heat dissipation section 53 is further cooled by transferring heat to the protruding heat dissipation section 53. As the specific gravity of the cooled coolant CL increases, the cooled coolant CL moves downward inside the protruding heat dissipation section 53 (arrow R2) and flows into the inside of the cylindrical member 41 through the connection hole 41i (arrow R3). In this way, the cooling medium C circulates between the inside of the housing 40 and the inside of the protruding heat dissipation section 53 while changing its state between liquid and gaseous, thereby cooling the stator 30.

[0076] The heat transfer section 80 transfers the heat generated in the stator 30 to the heat dissipation section 50. In other words, in this embodiment, the heat generated in the stator 30 is transferred to the heat dissipation section 50 by the cooling medium C as described above, and then transferred to the heat dissipation section 50 by the heat transfer section 80. The heat transferred to the heat dissipation section 50 is then dissipated to the outside of the motor 10 via the inner wall section 52b and the protruding heat dissipation section 53. As a result, the heat dissipation performance of the stator 30 can be improved.

[0077] As shown in Figure 3, the heat transfer section 80 includes a plurality of leaf spring sections 81. As shown in Figures 3 and 5, the plurality of leaf spring sections 81 are arranged at intervals along the circumferential direction. In this embodiment, 22 leaf spring sections 81 are provided. Therefore, according to this embodiment, since a plurality of leaf spring sections 81 are provided along the circumferential direction, variations in the amount of heat transferred from the stator 30 to the heat dissipation section 50 in the circumferential direction can be suppressed. As a result, the overall temperature rise of the stator 30 in the circumferential direction can be suppressed. Note that the number of leaf spring sections 81 is not limited to 22, and may be 21 or less, or 23 or more.

[0078] Each leaf spring portion 81 is an elastic plate. In this embodiment, the leaf spring portion 81 is made of, for example, a non-magnetic metal. The leaf spring portion 81 is made of a metal such as copper. Therefore, according to this embodiment, the heat transfer portion 80 can be manufactured by a simple processing method such as press working, and the increase in manufacturing man-hours and manufacturing costs of the heat transfer portion 80 can be suppressed.

[0079] As shown in Figure 2, at least a portion of each leaf spring portion 81 is located in the second space 16. As shown in Figure 3, each leaf spring portion 81 is fixed to the cylindrical member 41. As shown in Figure 5, each leaf spring portion 81 faces radially opposite the inner wall portion 52b. As shown in Figure 6, each leaf spring portion 81 has a fixing portion 81a, a first plate-shaped portion 81b, and a second plate-shaped portion 81c.

[0080] The fixing portion 81a is plate-shaped and protrudes radially. The plate surface of the fixing portion 81a faces axially. The radially inner end of the fixing portion 81a is located inside the cylindrical member 41. The radially outer end of the fixing portion 81a is located in the second space 16. The fixing portion 81a is passed radially through the through hole 41k. The fixing portion 81a is fitted into the through hole 41k. As a result, the leaf spring portion 81 is fixed to the housing 40. The heat transfer portion 80 is in contact with the stator 30 via the housing 40.

[0081] The first plate-like portion 81b is plate-shaped and protrudes from the radially outer end of the fixing portion 81a in a direction that faces downward, i.e., between one axial side and the radially outer side. The plate surface of the first plate-like portion 81b faces in a direction that faces upward and the radially outer side. The first plate-like portion 81b is positioned in the second space 16.

[0082] The second plate-shaped portion 81c is plate-shaped and protrudes downward from the tip of the first plate-shaped portion 81b, that is, in one axial direction. The plate surface of the second plate-shaped portion 81c faces radially. The second plate-shaped portion 81c is positioned in the second space 16. The radially outward-facing surface of the second plate-shaped portion 81c is in contact with the inner wall portion 52b. As a result, the heat transfer portion 80 is in contact with the heat dissipation portion 50. The second plate-shaped portion 81c receives a force from the cylindrical member 41 directed radially inward. As described above, the leaf spring portion 81 is elastic, so the leaf spring portion 81 elastically deforms radially inward. Therefore, a restoring force directed radially outward is applied to the leaf spring portion 81, and the radially outward-facing surface of the second plate-shaped portion 81c can stably contact the inner wall portion 52b. Therefore, according to this embodiment, the contact area between the second plate-shaped portion 81c and the heat dissipation portion 50 can be increased, allowing the heat generated in the stator 30 to be suitably transferred to the heat dissipation portion 50 via the heat transfer portion 80. Consequently, the heat dissipation performance of the stator 30 can be more suitably improved.

[0083] Furthermore, according to this embodiment, since the leaf spring portion 81 is in contact with the inner wall portion 52b located radially inward of the heat dissipation portion 50, the length of the leaf spring portion 81 in the radial direction can be shortened. Therefore, the heat generated in the stator 30 can be more effectively transferred to the heat dissipation portion 50, and the heat dissipation performance of the stator 30 can be more effectively improved.

[0084] As shown in Figure 6, the first plate-shaped portion 81b and the second plate-shaped portion 81c are positioned below the liquid level CLS of the coolant CL. In other words, the coolant CL is in contact with the heat transfer portion 80. That is, the cooling medium C is in contact with the heat transfer portion 80. Also, the cooling medium C housed in the second space 16 is in contact with the inner wall portion 52b. Therefore, according to this embodiment, the heat transferred from the stator 30 to the heat transfer portion 80 can be transferred to the heat dissipation portion 50 via the cooling medium C. As a result, the amount of heat transferred from the heat transfer portion 80 to the heat dissipation portion 50 can be increased. Consequently, the heat dissipation performance of the stator 30 can be more effectively improved.

[0085] Next, the heat dissipation attachment step Pr of the motor 10 manufacturing process in this embodiment, in which the heat dissipation section 50 is attached to the cylindrical member 41, will be described. In this specification, "workers, etc." includes workers and assembly equipment, etc. The work may be performed by workers alone, by assembly equipment alone, or by workers and assembly equipment together.

[0086] As shown in Figure 7, in the manufacturing process of the motor 10, in a process prior to the heat dissipation unit mounting process Pr, the worker installs the rotor 20, stator 30, second bearing 62, and second sealing member 64 inside the cylindrical member 41, and then fixes the inner cover member 42, to which the first bearing 61, first sealing member 63, and pressing member 67 are attached, to the upper end of the cylindrical member 41. In addition, multiple leaf spring sections 81 are fixed to the cylindrical member 41. At this time, as shown in Figure 7, the tip of the first plate-shaped section 81b and the second plate-shaped section 81c of each leaf spring section 81 are located radially outward from the tip of the first plate-shaped section 81b and the second plate-shaped section 81c of the leaf spring section 81 shown in Figure 6. Furthermore, the tip of the first plate-shaped section 81b and the second plate-shaped section 81c of each leaf spring section 81 are located radially outward from the O-ring 70. In the following explanation, the cylindrical member 41 to which the rotor 20, stator 30, etc., are attached and to which multiple leaf spring sections 81 are fixed, as described above, may be simply referred to as the cylindrical member 41.

[0087] Furthermore, as shown in Figure 7, in the manufacturing process of the motor 10, prior to the heat dissipation section mounting process Pr, workers fix the lower ring member 48, to which the O-ring 70 is fitted, and the outer cover member 43 to the heat dissipation section 50. In the following description, the heat dissipation section 50 to which the outer cover member 43 etc. are fixed may be simply referred to as the heat dissipation section 50.

[0088] As shown in Figure 7, in the heat dissipation unit installation process Pr, the worker moves the heat dissipation unit 50 downwards from the upper side of the cylindrical member 41 fixed to a jig, etc., and inserts the cylindrical member 41 axially into the fourth cylindrical part 52. Although not shown in the figure, when the O-ring 70 comes into contact with the first plate-shaped part 81b, the elastic plate spring part 81 elastically deforms radially inward, as shown by the dashed line in Figure 7, so that the O-ring 70 can move the heat dissipation unit 50 downwards without getting caught on the first plate-shaped part 81b. Furthermore, when the heat dissipation section 50 is moved downward, the O-ring 70 comes into contact with the tip of the second plate-shaped section 81c. However, in this embodiment, the second plate-shaped section 81c protrudes downward from the first plate-shaped section 81b, that is, the second plate-shaped section 81c protrudes in the same direction as the movement of the heat dissipation section 50 from the first plate-shaped section 81b. Therefore, it is possible to prevent the tip of the second plate-shaped section 81c from getting caught on the O-ring 70. Thus, according to this embodiment, in the heat dissipation section mounting process Pr, it is possible to prevent damage to the O-ring 70 due to contact between the O-ring 70 and the leaf spring section 81, and to prevent a decrease in the sealing performance of the O-ring 70. Therefore, according to this embodiment, for example, when inserting the cylindrical member 41 into the heat dissipation section 50, it is not necessary to use a jig or the like to pre-deform and hold the leaf spring section 81 radially inward to prevent contact between the leaf spring section 81 and the O-ring 70. Thus, it is possible to prevent an increase in the manufacturing man-hours and manufacturing costs of the motor 10.

[0089] When an operator further moves the heat dissipation section 50 downwards, the inner wall section 52b comes into contact with the second plate-shaped section 81c, and the leaf spring section 81 elastically deforms radially inward. This reduces the frictional force between the leaf spring section 81 and the inner wall section 52b. Furthermore, as described above, since the second plate-shaped section 81c protrudes downwards in the same direction as the movement of the heat dissipation section 50, it is possible to prevent the tip of the second plate-shaped section 81c from catching on the inner wall section 52b. As a result, the cylindrical member 41 can be easily inserted into the heat dissipation section 50, thereby suppressing an increase in the manufacturing man-hours for the motor 10. In addition, since deformation of the leaf spring section 81 is suppressed, the leaf spring section 81 and the inner wall section 52b can be kept in stable contact. Therefore, the heat transfer section 80 can stably transfer the heat generated in the stator 30 to the heat dissipation section 50. Thus, the heat dissipation performance of the stator 30 can be stabilized.

[0090] As shown in Figure 2, the worker moves the heat dissipation unit 50 downward until the inner circumferential surface of the base 48a of the lower ring member 48 is fitted to the outer circumferential surface of the lower end of the cylindrical portion 41a of the cylindrical member 41, and the outer cover member 43 and the inner cover member 42 come into contact, at which point the heat dissipation unit installation process Pr is completed.

[0091] According to this embodiment, the motor 10 comprises a rotor 20 rotatable about a central axis J, a stator 30 positioned radially outside the rotor 20, a cylindrical housing 40 surrounding the stator 30 from the radial outside, a heat dissipation section 50 positioned radially outside the housing 40 and facing the housing 40 with a radial gap in between, and a heat transfer section 80, at least a portion of which is located between the housing 40 and the heat dissipation section 50. The heat transfer section 80 is in contact with the heat dissipation section 50 and also in contact with the stator 30 via the housing 40. Therefore, heat generated in the stator 30 can be transferred to the heat dissipation section 50 via the housing 40 and the heat transfer section 80, and the heat generated in the stator 30 can be suitably dissipated to the outside of the motor 10 in the heat dissipation section 50. Thus, the heat dissipation performance of the stator 30 can be improved.

[0092] In this embodiment, the leaf spring portion 81 of the heat transfer section 80 is fixed to the cylindrical member 41, but the leaf spring portion may also be fixed to the inner wall portion 52b of the heat dissipation section 50. In this case, the leaf spring portion comes into contact with the outer surface of the cylindrical member 41, allowing the heat generated in the stator 30 to be transferred to the heat dissipation section 50 via the housing 40 and the heat transfer section.

[0093] <Second Embodiment> Figure 9 is a perspective view showing a part of the motor 210 of this embodiment. 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. In this embodiment, the cylindrical portion 241a of the cylindrical member 241 is provided with a plurality of through holes 241k. As shown in Figure 8, the through holes 241k are holes that penetrate the cylindrical portion 241a in the radial direction. In other words, the housing 240 has a plurality of through holes 241k that penetrate the housing 240 in the radial direction. As shown in Figure 9, when viewed radially, each through hole 241k is substantially rectangular in shape and extends in the axial direction. As shown in Figure 8, the upper end of the through hole 241k reaches the upper end of the cylindrical portion 241a. Each through hole 241k is provided spaced apart from each other along the circumferential direction. Although not shown, in this embodiment there are 23 through holes 241k. The other configurations of the housing 240 in this embodiment are the same as the other configurations of the housing 40 in the first embodiment.

[0094] As shown in Figure 10, the heat transfer section 280 of this embodiment includes an annular section 282 and a plurality of leaf spring sections 281. In this embodiment, the heat transfer section 280 is made of, for example, a non-magnetic metal. The heat transfer section 280 is made of a metal such as copper.

[0095] The annular portion 282 is an annular plate shape centered on the central axis J. The plate surface of the annular portion 282 faces axially. As shown in Figure 8, the annular portion 282 is positioned above the radially outer portion of the stator core 31. The downward-facing surface of the annular portion 282 contacts the upward-facing surface of the stator core 31 over its entire circumference. In other words, in this embodiment, the annular portion 282 is a contact portion that contacts the axially-facing surface of the stator 30. Therefore, according to this embodiment, since the heat transfer section 280 is in direct contact with the stator 30, the heat transfer efficiency from the stator 30 to the heat transfer section 280 can be increased. Furthermore, since the annular portion 282 is in contact with the stator core 31 over its entire circumference, the circumferential variation in the amount of heat transferred from the stator 30 to the heat transfer section 280 can be more effectively suppressed. As a result, the overall temperature rise of the stator 30 in the circumferential direction can be more effectively suppressed.

[0096] In this embodiment, the case in which the annular portion 282 functions as a contact portion that contacts the axially oriented surface of the stator 30 has been described. Thus, a configuration in which a part of the heat transfer portion directly contacts the stator 30 can also be adopted in the heat transfer portion 80 of the first embodiment. For example, the fixed portion 81a of the heat transfer portion 80 shown in Figure 6 may contact the axially oriented surface of the stator 30. That is, the fixed portion 81a of the first embodiment may function as a contact portion that contacts the stator 30.

[0097] As shown in Figure 10, each of the multiple leaf spring portions 281 is connected to the annular portion 282. Each of the multiple leaf spring portions 281 protrudes downward, that is, toward one side in the axial direction. Each of the multiple leaf spring portions 281 is an elastic plate. Each of the multiple leaf spring portions 281 is spaced apart along the circumferential direction. In this embodiment, 22 leaf spring portions 281 are provided. Note that the number of leaf spring portions 281 is not limited to 22, and may be 21 or less, or 23 or more. Although not shown, similar to each leaf spring portion 81 in Embodiment 1, each leaf spring portion 281 in this embodiment faces radially toward the inner wall portion 52b. As shown in Figure 8, at least a part of each leaf spring portion 281 is located in the second space 16. As shown in Figure 10, each leaf spring portion 281 has a connecting portion 281a and a plate-shaped portion 281b.

[0098] The connecting portion 281a protrudes radially outward from the annular portion 282. The connecting portion 281a is plate-shaped with its plate surface facing axially. As shown in Figure 8, the radially inner end of the connecting portion 281a is located inside the cylindrical member 241. The radially outer end of the connecting portion 281a is located in the second space 16. The connecting portion 281a is passed radially through the through hole 241k. The circumferentially facing surfaces on both sides of the connecting portion 281a are fitted into the inner surfaces of the through hole 41k. In this way, the heat transfer portion 280 is fixed to the housing 240. In this embodiment, the radially outer end of the connecting portion 281a is in contact with the inner wall portion 52b. However, the connecting portion 281a does not necessarily have to be in contact with the inner wall portion 52b.

[0099] The plate-shaped portion 281b is plate-shaped and protrudes downward, i.e., in one axial direction, from the radially outer end of the connecting portion 281a. The plate surface of the plate-shaped portion 281b faces radially. The plate-shaped portion 281b is positioned in the second space 16. The radially outward-facing surface of the plate-shaped portion 281b is in contact with the inner wall portion 52b. In other words, multiple leaf spring portions 281 are in contact with the heat dissipation portion 50. The plate-shaped portion 281b receives a force from the cylindrical member 41 directed radially inward. As described above, since the leaf spring portion 281 is elastic, the leaf spring portion 281 elastically deforms radially inward. A restoring force directed radially outward is applied to the leaf spring portion 281, and the radially outward-facing surface of the plate-shaped portion 281b is in stable contact with the inner wall portion 52b. Therefore, according to this embodiment, the contact area between the plate-shaped portion 281b and the heat dissipation portion 50 can be increased, allowing heat generated in the stator 30 to be suitably transferred to the heat dissipation portion 50 via the heat transfer portion 280. Consequently, the heat dissipation performance of the stator 30 can be suitably improved.

[0100] Furthermore, according to this embodiment, multiple leaf spring sections 281 are provided along the circumferential direction, and each leaf spring section 281 is in contact with the heat dissipation section 50. Therefore, variations in the amount of heat transferred from the stator 30 to the heat dissipation section 50 via the heat transfer section 280 in the circumferential direction can be suppressed. As a result, the overall temperature rise of the stator 30 in the circumferential direction can be suppressed. The other configurations of the heat transfer section 280 in this embodiment are the same as the other configurations of the heat transfer section 80 in the first embodiment.

[0101] Next, the heat transfer unit mounting process Ph, in which the heat transfer unit 280 is attached to the cylindrical member 241, will be described as part of the manufacturing process of the motor 210 in this embodiment. As shown in Figure 11, in the manufacturing process of the motor 210, prior to the heat transfer unit mounting process Ph, the worker or other personnel pre-installs the rotor 20, stator 30, second bearing 62, and second sealing member 64 inside the cylindrical member 241. In the following description, the cylindrical member 241 with the rotor 20, stator 30, etc., attached may be simply referred to as the cylindrical member 241.

[0102] In the heat transfer unit installation process Ph, the worker moves the heat transfer unit 280 downward from the upper side of the cylindrical member 241 fixed to a jig, inserting the annular portion 282 of the heat transfer unit 280 into the interior of the cylindrical member 241 through the opening 41g, and passing the connecting portion 281a through the through hole 241k. At this time, the plate-shaped portion 281b moves downward on the radially outer side of the cylindrical portion 241a. The worker further moves the heat transfer unit 280 downward, and as shown in Figure 8, when the downward-facing surface of the annular portion 282 comes into contact with the upward-facing surface of the stator core 31, the heat transfer unit installation process Ph is completed. At this time, as described above, the circumferentially facing surfaces of each connecting portion 281a are fitted into the inner surfaces of the through hole 41k, and the heat transfer unit 280 is fixed to the housing 240.

[0103] Therefore, according to this embodiment, since the multiple leaf spring portions 281 of the heat transfer section 280 are connected to the annular portion 282, the multiple leaf spring portions 281 can be positioned between the housing 240 and the heat dissipation section 50 in a single step of attaching the heat transfer section 280 to the housing 240. As a result, an increase in manufacturing man-hours for positioning the heat transfer section 280 can be suppressed. In addition, since the heat transfer section 280 has multiple leaf spring portions 281, the number of parts in the heat transfer section 280 can be reduced. Consequently, an increase in manufacturing man-hours and the number of parts in the motor 10 can be suppressed.

[0104] In this embodiment, the heat transfer section 280 is composed of a single component, but the heat transfer section may be composed of two or more components. For example, it may be composed of multiple components that divide the heat transfer section in the circumferential direction. For example, if the heat transfer section is composed of two components that divide the heat transfer section in the circumferential direction, the annular portion of each component will be semicircular, and multiple leaf spring portions will be connected to each semicircular annular portion. This makes it easier to fix the heat transfer section to the housing and suppresses an increase in the manufacturing man-hours of the motor.

[0105] <Third Embodiment> Figure 13 is a partial cross-sectional perspective view showing the heat transfer section 380 of the motor 310 of this embodiment. In the following description, components identical to those in the first embodiment described above are denoted by the same reference numerals, and their descriptions are omitted. In this embodiment, the heat transfer section 380 includes a plurality of protrusions 381 provided on the inner wall portion 352b of the fourth cylindrical portion 352 of the heat dissipation section 350. The plurality of protrusions 381 are provided on the inner circumferential surface of each inner wall portion 352b, that is, on the radially inner surface of the heat dissipation section 350. Each of the plurality of protrusions 381 protrudes radially inward from the inner circumferential surface of the inner wall portion 352b. The plurality of protrusions 381 are arranged at equal intervals from each other along the circumferential direction. In this embodiment, 45 protrusions 381 are provided. The number of protrusions 381 is not limited to 45, and may be 45 or less. In this embodiment, each protrusion 381 is a part of the inner wall portion 352b. In this embodiment, each protrusion 381 is formed by a simple processing method such as deep drawing. Therefore, according to this embodiment, it is possible to suppress an increase in the manufacturing man-hours and the number of parts of the heat transfer section 380. The configuration of the protrusion 381 is not limited to this embodiment, and the protrusion can also be provided by fixing a separate member from the heat dissipation member 351 to the inner wall section 352b. In this embodiment, the protrusion 381 has a first side wall section 381a, a second side wall section 381b, and a third side wall section 381c.

[0106] As shown in Figure 13, the first side wall portion 381a and the second side wall portion 381b protrude radially inward from the inner wall portion 352b. The first side wall portion 381a and the second side wall portion 381b are plate-shaped with their surface facing circumferentially. The first side wall portion 381a is the portion of the protruding portion 381 located on one side in the circumferential direction. The second side wall portion 381b is the portion of the protruding portion 381 located on the other side in the circumferential direction. Viewed in the circumferential direction, the first side wall portion 381a and the second side wall portion 381b have a roughly bow-like shape that protrudes radially inward. Viewed in the circumferential direction, the first side wall portion 381a and the second side wall portion 381b overlap each other.

[0107] The third side wall portion 381c connects the first side wall portion 381a and the second side wall portion 381b. As shown in Figure 13, when viewed in the circumferential direction, the third side wall portion 381c is an arc shape projecting radially. The upper and lower ends of the third side wall portion 381c are connected to the inner wall portion 52b, respectively. The third side wall portion 381c has a first outer surface 381d and a second outer surface 381e.

[0108] The first outer surface 381d is the lower portion of the radially inward-facing surface of the third side wall portion 381c. Viewed in the circumferential direction, the first outer surface 381d is positioned radially inward as it moves from the lower side of the protrusion 381, i.e., one end on the axial side, to the upper side, i.e., the other end on the axial side. The first outer surface 381d is arc-shaped and protrudes radially inward. Therefore, according to this embodiment, similar to the heat dissipation mounting process Pr of Embodiment 1, when a worker moves the heat dissipation portion 350 downward from the upper side of the cylindrical member 41 fixed to a jig, etc., and inserts the cylindrical member 41 into the fourth cylindrical portion 352 in the axial direction, it is possible to prevent the protrusion 381 from catching on the outer circumferential surface of the cylindrical portion 41a. As a result, the cylindrical member 41 can be easily inserted into the heat dissipation portion 350, and an increase in the manufacturing man-hours of the motor 310 can be suppressed.

[0109] The second outer surface 381e is the upper portion of the radially inward-facing surface of the third side wall portion 381c. Viewed in the circumferential direction, the second outer surface 381e is positioned radially inward as it extends downward from the upper end of the protruding portion 381. Furthermore, the second outer surface 381e is arc-shaped and protrudes radially inward.

[0110] As shown in Figure 12, the radially inner portion of the protrusion 381 contacts the outer circumferential surface of the cylindrical portion 41a. That is, the protrusion 381 contacts the housing 40. In other words, the protrusion 381 contacts the stator 30 via the housing 40. Therefore, according to this embodiment, the heat generated in the stator 30 can be suitably transferred to the heat dissipation portion 350 via the housing 40 and the heat transfer portion 380, and the heat generated in the stator 30 can be suitably dissipated to the outside of the motor 10 in the heat dissipation portion 350. Thus, the heat dissipation performance of the stator 30 can be improved.

[0111] Furthermore, according to this embodiment, multiple protrusions 381 are provided along the circumferential direction, and each protrusion 381 contacts the housing 40, so that variations in the amount of heat transferred from the stator 30 to the heat dissipation section 350 via the heat transfer section 380 can be suppressed in the circumferential direction. As a result, the overall temperature rise of the stator 30 in the circumferential direction can be suppressed. The other configurations of the heat dissipation section 350 in this embodiment are the same as the other configurations of the heat dissipation section 50 in the first embodiment.

[0112] As shown in Figure 12, in the radial direction, the contact portion Pc of the housing 40, which is the part that contacts the protruding portion 381, overlaps with the stator 30. Therefore, according to this embodiment, the distance between the stator 30 and the heat transfer portion 380 can be shortened, and the heat from the stator 30 can be transferred to the heat transfer portion 380 more efficiently via the housing 40. Thus, the heat dissipation performance of the stator 30 can be more effectively improved.

[0113] In this embodiment, the protrusion 381 of the heat transfer section 380 is provided on the heat dissipation section 350, but the protrusion may be provided on the outer circumferential surface of the cylindrical section 41a. For example, the protrusion may be formed by drawing the cylindrical section 41a, or it may be provided by fixing a separate member to the outer circumferential surface of the cylindrical section 41a. In this case, the heat generated in the stator 30 can be transferred to the heat dissipation section via the housing and the heat transfer section by the protrusion contacting the inner wall.

[0114] The present invention is not limited to the embodiments described above, and other configurations and methods may be adopted within the scope of the technical idea of ​​the present invention. The configuration of the heat dissipation section is not particularly limited as long as it can dissipate the heat of the cooling medium to the outside. For example, the heat dissipation section may be placed above the stator. In this case, the gas can flow more easily into the interior of the protruding section by the non-contact heat dissipation section, thereby more favorably improving the heat dissipation performance of the stator. The material of the heat dissipation section is not particularly limited and may be a material other than metal.

[0115] The type of cooling medium is not particularly limited, as long as it can cool the stator. The cooling medium does not have to be a fluorine compound. The cooling medium does not have to be insulating. In this case, the stator and other components may be insulated.

[0116] The applications of the motor to which the present invention is applied are not particularly limited. The motor may be mounted on equipment other than unmanned aerial vehicles such as unmanned aircraft. Furthermore, the configurations and methods described herein can be combined as appropriate, within the bounds of what is not inconsistent with each other. [Explanation of symbols]

[0117] 10,210,310…Motor, 20…Rotor, 30…Stator, 32…Coil, 40,240…Housing, 41k,241k…Through-hole, 50,350…Heat dissipation section, 52b,352b…Inner wall section, 53…Protruding heat dissipation section, 80,280,380…Heat transfer section, 81,281…Leaf spring section, 81b…First plate-shaped section, 81c…Second plate-shaped section, 281a…Connecting section, 281b…Plate-shaped section, 282…Ring section (contact section), 381…Protruding section, 381d…First outer surface, C…Cooling medium, CLS…Liquid level, J…Central axis

Claims

1. A rotor that can rotate around its central axis, A stator is positioned radially outward from the rotor, A cylindrical housing surrounding the stator from the radially outer side, A heat dissipation section is positioned radially outward from the housing and faces the housing with a gap in the radial direction between them, A heat transfer section, at least a portion of which is located between the housing and the heat dissipation section, Equipped with, The heat transfer section is In contact with the heat dissipation part, The stator is in direct contact with the stator, or in contact with the housing through the housing. The annular portion centered on the aforementioned central axis, It includes multiple leaf spring sections that are elastic and arranged along the circumferential direction, A motor in which multiple leaf spring portions are connected to the annular portion, protrude toward one side in the axial direction, and contact the heat dissipation portion.

2. A rotor that can rotate about a central axis, A stator is positioned radially outward from the rotor, A cylindrical housing surrounding the stator from the radially outer side, A heat dissipation section is positioned radially outward from the housing and faces the housing with a gap in the radial direction between them, A heat transfer section, at least a portion of which is located between the housing and the heat dissipation section, Equipped with, The heat transfer section is In contact with the heat dissipation part, The stator is in direct contact with the stator, or in contact with the housing through the housing. The heat transfer section has elastic leaf spring sections arranged circumferentially, and a contact section that contacts the axially oriented surface of the stator. The housing has a plurality of through holes that penetrate radially through the housing, The motor has a leaf spring portion that protrudes radially outward from the contact portion and has a connecting portion that passes radially through the through hole.

3. The leaf spring portion has a first plate-shaped portion that protrudes in a direction between one axial side and the radially outward direction, and a second plate-shaped portion that protrudes from the tip of the first plate-shaped portion in the axial direction. The motor according to claim 1 or 2, wherein at least the second plate-shaped portion is in contact with the heat dissipation portion.

4. The motor according to any one of claims 1 to 3, wherein the heat dissipation portion is in the shape of a heat dissipation fin, having a plurality of protruding heat dissipation portions that extend outward and are spaced apart along the circumferential direction.

5. The heat dissipation section has a plurality of inner wall sections that connect the radially inner ends of adjacent protruding heat dissipation sections. The motor according to claim 4, wherein the heat transfer portion is in contact with the inner wall portion.

6. The housing and the heat dissipation section are equipped with a cooling medium housed inside them. The cooling medium is in contact with at least the stator and the heat dissipation section. The aforementioned protruding heat dissipation portion is hollow, At least a portion of the protruding heat dissipation portion is positioned vertically above the liquid surface of the cooling medium. The motor according to claim 5, wherein the inside of the housing and the portion of the protruding heat dissipation part located vertically above the liquid level of the cooling medium are connected.

7. The motor according to claim 6, wherein the cooling medium is in contact with the heat transfer section.

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