Rotating electric machine

Abstract

To provide a rotating electric machine with high cooling efficiency. [Solution] The rotating electric machine is a rotating electric machine 100 that is driven by the supply of electricity, and comprises a stator 20 and a rotor 30 that rotates about a rotation axis and is arranged with an axial gap 50 between it and the stator in the axial direction in which the rotation axis extends. The rotor comprises a magnet 31, a magnet holding part 36 that holds the magnet, and a plurality of support columns 37 that support the magnet holding part and form a flow path through which air flows from the inner circumference to the outer circumference. The rotating electric machine comprises a housing 40 that houses the stator and rotor inside and has a heat dissipation promoting part 42 on its outer surface, and a heat transfer promoting part 71 that promotes heat transfer from the air that has passed through the axial gap to the housing.

Description

Technical Field

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[0001] The disclosure in this specification relates to a rotating electric machine.

Background Art

[0002] Patent Document 1 discloses an axial-gap type motor. In an axial-gap type motor, a rotor and a stator are arranged in the axial direction. In this motor, the rotor and the stator are housed in a motor housing. The description of the prior art document is incorporated herein by reference as an explanation of the technical elements in this specification.

Prior Art Document

Patent Document

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the above Patent Document 1, it is considered that heat is likely to be trapped between the rotor and the stator. If heat is trapped between the rotor and the stator, there is a concern that the temperature of the motor will rise excessively. From the above viewpoints or other viewpoints not mentioned, further improvements are required for the rotating electric machine.

[0005] One object of the disclosure is to provide a rotating electric machine with a high cooling effect.

Means for Solving the Problems

[0006] The rotating electric machine disclosed herein is a rotating electric machine (100) driven by power supply, comprising a stator (20), A rotor (30) rotates around a rotation axis and is positioned with an axial gap (50) between it and the stator in the axial direction in which the rotation axis extends, The rotor comprises a magnet (31), a magnet holder (36) that holds the magnet, and a plurality of support columns (37) that support the magnet holder and form a flow path through which air flows from the inner circumference to the outer circumference. The rotating electric machine comprises a housing (40) that houses the stator and rotor internally and has a heat dissipation promotion section (42) on its outer surface, It is equipped with heat transfer promoting sections (71, 271, 371, 443, 571, 647, 726) that facilitate heat transfer from air passing through the axial gap to the housing.

[0007] The disclosed rotating electric machine includes a heat transfer promoting unit that facilitates heat transfer from the air passing through the axial gap to the housing. This increases the heat transfer rate from the air inside the rotating electric machine to the housing. Therefore, a rotating electric machine with a high cooling effect can be provided.

[0008] The various embodiments disclosed in this specification employ different technical means to achieve their respective objectives. The claims and the reference numerals in parentheses in this section are illustrative in their correspondence with the embodiments described later and are not intended to limit the technical scope. The objectives, features, and effects disclosed in this specification will become clearer by referring to the subsequent detailed description and the accompanying drawings. [Brief explanation of the drawing]

[0009] [Figure 1] This is a cross-sectional view of a rotating electric machine. [Figure 2] This is a cross-sectional view taken along line II-II in Figure 1. [Figure 3] This is a cross-sectional view showing the shape of the heat-absorbing fins. [Figure 4] This is an explanatory diagram illustrating the airflow inside a rotating electric machine. [Figure 5] This is a cross-sectional view of the rotating electric machine in the second embodiment. [Figure 6] This is a cross-sectional view showing the shape of the heat-absorbing fins in the second embodiment. [Figure 7] This is a cross-sectional view showing the shape of the heat-absorbing fins in the third embodiment. [Figure 8] This is a cross-sectional view of the rotating electric machine in the fourth embodiment. [Figure 9] This is a cross-sectional view of the rotating electric machine in the fifth embodiment. [Figure 10] This is a cross-sectional view of the rotating electric machine in the sixth embodiment. [Figure 11] This is a cross-sectional view of the rotating electric machine in the seventh embodiment. [Modes for carrying out the invention]

[0010] Multiple embodiments will be described with reference to the drawings. In multiple embodiments, functionally and / or structurally corresponding and / or related parts may be given the same reference numeral, or reference numerals that differ by hundreds or more digits. For corresponding and / or related parts, refer to the description of other embodiments.

[0011] <First Embodiment> In Figure 1, the rotating electric machine 100 is an axial gap type motor. The rotating electric machine 100 can be mounted on an aircraft, for example, flying in the atmosphere, and used as a device to rotate the propeller of the aircraft.

[0012] The rotating electric machine 100 comprises a shaft 10, a stator 20, and a rotor 30. The shaft 10 supports the rotor 30. The shaft 10 rotates together with the rotor 30 around the axis of rotation Cm. The centerline of the shaft 10 coincides with the axis of rotation Cm. The stator 20 and rotor 30 are arranged side by side in the axial direction AD, along which the axis of rotation Cm, which is the axis of the rotating electric machine 100, extends. Figure 1 is a cross-sectional view of the rotating electric machine 100 cut along the axis of rotation Cm of the rotor 30.

[0013] The circumferential direction CD is the rotation direction of the rotating electrical machine 100. The radial direction RD is the direction approaching the shaft 10 or the direction away from the shaft 10. The outer side of the radial direction RD may be referred to as the outer peripheral side, and the inner side of the radial direction RD may be referred to as the inner peripheral side. The axial direction AD may be referred to as the axial direction.

[0014] The stator 20 is a stator. The stator 20 includes a plurality of coil units each including a stator core 22 and a coil portion 21 wound around the stator core 22. The stator 20 is configured in an annular shape by arranging a plurality of coil units in the circumferential direction CD. The rotation axis Cm coincides with the center line of the stator 20.

[0015] The rotor 30 is a rotor. The rotor 30 rotates relative to the stator 20. The rotor 30 rotates about the rotation axis Cm. The rotation axis Cm is the center line of the rotor 30.

[0016] The rotor 30 includes a drive-side rotor 30d and a rear-side rotor 30r. The rotating electrical machine 100 is a double-rotor type motor. The rotating electrical machine 100 may be referred to as a double-axial motor. The drive-side rotor 30d and the rear-side rotor 30r are arranged in the axial direction AD via the stator 20.

[0017] The rotor 30 comprises a magnet 31 and a fixing member 35. The fixing member 35 comprises a magnet holder 36, a support column 37, and a support column fixing part 38. The magnet holder 36 and the support column fixing part 38 are disc-shaped. The diameter of the magnet holder 36 is larger than the diameter of the support column fixing part 38. The support column fixing part 38 is fixed to the shaft 10. The support column fixing part 38 comprises a base and a disc part. The base is the part that is fixed to the shaft 10. The disc part is the part that extends outward from the base in the radial direction RD. The disc part is an annular plate shape that is thinner than the base. The shaft 10 comprises a convex annular part that protrudes outward in the radial direction RD from a cylindrical shaft body that forms the main body of the shaft 10. The convex annular part is formed in the center of the axial direction AD. The base of the support column fixing part 38 is fixed to the shaft 10 at a position where it contacts a convex ring portion provided on the shaft 10 from the axial direction AD. The magnet holding part 36 and the support column fixing part 38 are connected by a support column 37. The support column 37 is a hollow column shape.

[0018] The magnet 31 is embedded in a recess provided in the magnet holding portion 36 and is held in place by adhesive bonding. The magnet 31 is fixed to the shaft 10 via a fixing member 35. Therefore, the rotor 30 rotates integrally with the shaft 10.

[0019] Multiple magnets 31 are arranged in the circumferential direction CD on both the drive rotor 30d and the rear rotor 30r. The magnets 31 are composed of permanent magnets and form a magnetic field. The magnets 31 generate magnetic flux on both the drive rotor 30d and the rear rotor 30r. The magnets 31 on the drive rotor 30d and the rear rotor 30r are arranged in the axial direction AD via the stator 20. The magnets 31 are positioned opposite the stator 20 in the axial direction AD.

[0020] The fixing member 35 is made of a resin material or the like and has electrical insulating properties. For example, the fixing member 35 is made of CFRP, which is carbon fiber reinforced plastic.

[0021] The rotating electric machine 100 comprises a housing 40. The housing 40 comprises an electric machine outer wall 41 and an end plate 45. The end plate 45 comprises a drive frame 45d and a rear frame 45r. The drive frame 45d is the end plate 45 attached to the side where the shaft 10 is connected to the drive object of the rotating electric machine 100. The rear frame 45r is the end plate 45 attached to the opposite side from the drive frame 45d. The housing 40 houses the stator 20 and the rotor 30.

[0022] The outer wall 41 of the electric motor is formed in a cylindrical shape and extends in the axial direction AD. The outer wall 41 of the electric motor covers the stator 20 and rotor 30 from the outer circumference. The end plate 45 is formed in a disc shape and extends in the radial direction RD.

[0023] On the outer surface of the electrical machine outer wall 41, which is the side opposite to the internal space forming the housing 40, heat dissipation fins 42 are formed. Multiple heat dissipation fins 42 are provided continuously from one open end to the opposite open end of the cylindrical electrical machine outer wall 41. The heat dissipation fins 42 promote heat dissipation from the electrical machine outer wall 41 to the air surrounding the rotating electrical machine 100. The heat dissipation fins 42 provide an example of a heat dissipation promoting part.

[0024] The end plates 45 are arranged in the axial direction AD via the electrical outer wall 41. The end plates 45 are fixed to the electrical outer wall 41 by fasteners such as bolts. The end plates 45 are attached to the open end of the electrical outer wall 41 and cover this open end from both sides in the axial direction AD.

[0025] The drive frame 45d has a connection terminal 29 on the side opposite to the internal space of the housing 40. The drive frame 45d has an opening that connects the internal space and the external space of the housing 40. The connection terminal 29 and the coil section 21 are electrically connected by a connection section 25 that extends through the opening of the drive frame 45d. The connection section 25 can also be described as a wiring section that provides wiring for supplying current to the necessary locations.

[0026] The connection part 25 protrudes from an opening in the drive frame 45d to the outside of the drive frame 45d. The coil part 21 is connected to the inverter via the connection part 25 and the connection terminal 29. By supplying alternating current to the coil part 21 by the inverter, an electromagnetic force is generated in the stator 20. This electromagnetic force generates an attractive or repulsive force in the magnet 31, causing the shaft 10 and rotor 30, which are rotatably supported by the end plate 45, to rotate. In this way, the rotating electric machine 100 is driven as a motor by the supply of power. The rotating electric machine 100 also functions as a generator during regeneration.

[0027] The connection part 25 is not limited to a component that electrically connects the coil part 21 and the connection terminal 29. For example, a component that electrically connects two coil parts 21 together is also included in the connection part 25. When the connection part 25 electrically connects two coil parts 21 together, the connection can be completed inside the housing 40, so it does not penetrate the opening of the drive frame 45d.

[0028] The rotating electric machine 100 is equipped with an axial gap 50. The axial gap 50 is the gap between the stator 20 and the rotor 30 in the axial direction AD. The axial gap 50 forms a disc-shaped space extending radially RD between the stator 20 and the rotor 30. The axial gap 50 includes the gap between the stator 20 and the drive-side rotor 30d and the gap between the stator 20 and the rear-side rotor 30r. The axial gap 50 provides an example of an axial gap.

[0029] The rotating electric machine 100 is equipped with bearings 61. The bearings 61 rotatably support the shaft 10. The bearings 61 include a drive bearing fixed to the drive frame 45d and a rear bearing fixed to the rear frame 45r.

[0030] The internal space of the housing 40 includes an outer peripheral space 51, an inner peripheral space 52, and a frame space 53. The outer peripheral space 51 is the space on the outer periphery side of the rotor 30. The outer peripheral space 51 is the space between the rotor 30 and the electric outer peripheral wall 41 in the radial direction RD. The outer peripheral space 51 forms an annular space that extends in an annular manner in the circumferential direction CD along the outer peripheral edge of the rotor 30. The outer peripheral space 51 is on the outer peripheral side of the axial gap 50. The axial gap 50 is open radially outward and is therefore ventilated to the outer peripheral space 51.

[0031] The inner circumferential space 52 is a space located on the inner side of the rotor 30. The inner circumferential space 52 is the space between the rotor 30 and the shaft 10 in the radial direction RD. The inner circumferential space 52 forms an annular space that extends in a ring shape in the circumferential direction CD along the inner edge of the rotor 30. The inner circumferential space 52 is located on the inner side of the axial gap 50.

[0032] The frame space 53 is the space on the opposite side of the axial gap 50 from the disc-shaped magnet holder 36. The frame space 53 is the space between the rotor 30 and the end plate 45 in the axial direction AD. The frame space 53 extends radially RD along the inner surface of the end plate 45. The frame space 53 connects the outer peripheral space 51 and the inner peripheral space 52.

[0033] Multiple support columns 37 are arranged spaced apart from each other, inside the radial RD of the stator 20. A space created by the support columns 37 exists between the magnet holding portion 36 and the support column fixing portion 38. This space is referred to as the inter-support column space 54. The inter-support column space 54 is located inside the radial RD of the stator 20 and outside the radial RD of the inner circumferential space 52. The inter-support column space 54 is provided between the inner circumferential space 52 and the axial gap 50 in the radial RD, and connects the inner circumferential space 52 and the axial gap 50.

[0034] As shown in Figure 2, multiple support columns 37 are arranged in a circumferential direction CD. Multiple support columns 37 arranged on one circumference form a circumferential row. In one circumferential row, a space 54 is created between adjacent support columns 37. The space 54 between support columns forms a passage for air to flow.

[0035] In the circumferential row, the support columns 37 are arranged at equal intervals. The number of support columns 37 in the circumferential row is 12. The support columns 37 are formed such that the internal space of the support column 37, when cut by a plane perpendicular to the rotation axis Cm, increases as the position closer to the outside of the radial direction RD approaches.

[0036] The heat dissipation fins 42 are arranged radially on the outside of the outer wall 41 of the electrical unit. The heat dissipation fins 42 are rectangular plate-shaped. The heat dissipation fins 42 are arranged at equal intervals along the circumferential direction CD.

[0037] In Figure 1, a fin casing 70 is provided inside the housing 40. The fin casing 70 is located in the outer peripheral space 51. The fin casing 70 is annular in shape and is in contact with the inside of the electrical outer peripheral wall 41. A highly heat-conductive grease is provided between the fin casing 70 and the electrical outer peripheral wall 41. Heat-absorbing fins 71 are formed on the fin casing 70. Details of the heat-absorbing fins 71 will be described later.

[0038] The fin casing 70 comprises a drive-side fin casing 70d and a rear-side fin casing 70r. The drive-side fin casing 70d is positioned opposite the drive-side rotor 30d in the radial direction RD. On the other hand, the rear-side fin casing 70r is positioned opposite the rear-side rotor 30r in the radial direction RD. The fin casing 70 may consist of either the drive-side fin casing 70d or the rear-side fin casing 70r.

[0039] The electrical outer wall 41, end plate 45, and fin casing 70 are formed from an aluminum alloy or other metal material, and have higher thermal conductivity than the resin material of the fixing member 35.

[0040] In Figure 3, the heat-absorbing fin 71 is provided projecting vertically from the inside of the fin casing 70 toward the inside in the radial direction RD. The heat-absorbing fin 71 is formed integrally with the fin casing 70. The heat-absorbing fin 71 has a gap where the connecting portion 25 and the like are arranged, but overall it has a substantially annular shape. The heat-absorbing fin 71 may also be formed in an annular shape without a gap.

[0041] Four heat-absorbing fins 71 are formed, arranged at equal intervals in the axial direction AD. The protrusion amounts of the four heat-absorbing fins 71 are equal to each other. The protrusion amount of the heat-absorbing fins 71 is greater than the thickness of the base portion of the fin casing 70, which is the portion where the heat-absorbing fins 71 are not formed. The protrusion amount of the heat-absorbing fins 71 is greater than the gap length, which is the length of the axial gap 50 in the axial direction AD. The protrusion amount of the heat-absorbing fins 71 is less than the protrusion amount of the heat-dissipating fins 42 in the radial direction RD. The heat-absorbing fins 71 provide an example of a heat transfer promotion section.

[0042] The airflow inside the rotating electric machine 100 is described below. When the rotor 30 rotates in conjunction with the operation of the rotating electric machine 100, the rotor 30 functions like a centrifugal fan such as a sirocco fan, generating cooling air inside the rotating electric machine 100. This cooling air is generated by the flow of air or other gases present inside the housing 40.

[0043] The cooling air includes a wall flow that flows circumferentially CD along the inside of the outer wall 41 of the electric motor, and a circulating flow that circulates around the magnet holding portion 36 of the rotor 30.

[0044] Wall flow is the airflow generated by the rotating rotor 30 directing air along the circumferential direction CD. The wall flow mainly flows in the outer peripheral space 51, which is the space between the rotor 30 and the outer peripheral wall 41 of the electric motor. A portion of the wall flow is guided by the heat absorption fins 71 and flows in a ring shape between adjacent heat absorption fins 71. In Figure 3, this wall flow is illustrated using dashed arrows.

[0045] In Figure 4, the circulating flow is the airflow mainly generated by the rotating support column 37 pushing air outward in the radial direction RD. As the support column 37 rotates, air is drawn in from the inner circumferential space 52. The air drawn in from the inner circumferential space 52 passes through the space between the support columns 54 and the axial gap 50, and reaches the outer circumferential space 51. After that, it passes from the outer circumferential space 51 through the frame space 53 and returns to the inner circumferential space 52. The circulating flow repeats this series of airflows. In Figure 4, this circulating flow is illustrated using dashed arrows.

[0046] The circulating flow caused by the rotation of the drive rotor 30d passes through the axial gap 50 and the outer peripheral space towards the frame space 53. That is, in the outer peripheral space 51 near the drive rotor 30d, the circulating flow has a velocity component that approaches the drive frame 45d. Similarly, the circulating flow caused by the rotation of the rear rotor 30r passes through the axial gap 50 and the outer peripheral space 51 towards the frame space 53. That is, in the outer peripheral space 51 near the rear rotor 30r, the circulating flow has a velocity component that approaches the rear frame 45r.

[0047] Wall flow is the airflow generated by the rotating rotor 30 directing air along the circumferential direction CD. Wall flow mainly occurs in the outer peripheral space 51, which is the space between the rotor 30 and the outer peripheral wall 41 of the electric motor.

[0048] The wall flow contained in the cooling air has a higher flow velocity than the circulating flow contained in the cooling air. For this reason, the wall flow is the dominant flow in the cooling air, and the circulating flow is a secondary flow. The cooling air flowing through the outer peripheral space 51 is a combination of the wall flow and the circulating flow. Therefore, the outer peripheral space 51 has a velocity component in the circumferential direction CD as well as a velocity component in the direction approaching the end plate 45.

[0049] The heat transfer in the rotating electric machine 100 is described below. The heat generated in the magnet 31 is more easily transferred to the air from the axial gap 50 side than from the magnet holder 36, which has a lower thermal conductivity than metal. This is because the magnet 31 is exposed and therefore directly exposed to the air. The heat generated in the stator 20 is also more easily transferred to the air from the axial gap 50 side, where a circulating flow occurs. Therefore, the heat from the stator 20 and rotor 30 is transferred to the circulating air passing through the axial gap 50 and released into the outer peripheral space 51 by this air.

[0050] The cooling air flowing through the outer peripheral space 51 mainly flows along the circumferential direction CD inside the fin casing 70, thereby transferring heat from the cooling air to the fin casing 70. In particular, since the fin casing 70 has heat-absorbing fins 71 formed on it, it comes into contact with more air and can transfer heat more efficiently than if the heat-absorbing fins 71 were not formed. In other words, because the heat transfer area is increased by the heat-absorbing fins 71, heat from the air can be transferred to the fin casing 70 more efficiently. The fin casing 70 is in contact with the outer peripheral wall 41 of the electric machine. Therefore, the heat transferred to the fin casing 70 is transferred to the outer peripheral wall 41 of the electric machine, and then transferred to the air in the space outside the rotating electric machine 100 from the heat-dissipating fins 42 provided on the outer peripheral wall 41.

[0051] A portion of the cooling air flowing through the outer peripheral space 51 flows through the frame space 53 as a circulating flow. In the frame space 53, the heat from the cooling air is released to the outside of the rotating electric machine 100 via the end plate 45.

[0052] The cooling air dissipates heat in the outer peripheral space 51 and frame space 53, returns to the inner peripheral space 52, then passes through the space between the support columns 54 and flows again towards the axial gap 50 to cool the stator 20 and rotor 30. In the rotating electric machine 100, a series of cooling airflows are generated while the rotor 30 is rotating.

[0053] The effects of the above-described embodiment will now be explained. According to the above-described embodiment, a heat-absorbing fin 71 is provided to promote heat transfer from the air that has passed through the axial gap 50 to the housing 40. Therefore, it is easier to transfer heat from the air inside the rotating electric machine 100 to the housing 40 compared to when the heat-absorbing fin 71 is not provided. Consequently, it is easier to transfer the heat from the air inside the rotating electric machine 100 to the outside of the rotating electric machine 100 via the housing 40, thereby cooling the temperature of the rotating electric machine 100. Thus, a rotating electric machine 100 with a high cooling effect can be provided.

[0054] Rotating electric machines 100 mounted on aircraft are often required to have higher output than those mounted on mobile vehicles such as cars or non-mobile products such as washing machines. The higher the output, the larger the current flowing through the rotating electric machine 100 tends to be, and the greater the amount of heat generated. Therefore, improving the cooling effect of the rotating electric machine 100 is particularly beneficial when it is mounted on an aircraft.

[0055] Resin materials tend to have lower heat resistance temperatures compared to metal materials. Therefore, when resin parts are used inside the rotating electric machine 100, or when parts are fixed together with adhesive, it is necessary to keep the temperature of the rotating electric machine 100 low. Accordingly, improving the cooling effect of the rotating electric machine 100 is particularly beneficial when resin materials or adhesives are used in the rotating electric machine 100.

[0056] The heat-absorbing fins 71 are located in the outer peripheral space 51 between the rotor 30 and the outer peripheral wall 41 of the electric motor. This allows for an increased heat transfer area for transferring heat from the air to the housing 40 in the outer peripheral space 51, where a large amount of cooling air flows. Therefore, the cooling effect can be improved more efficiently compared to when the fins are placed in a location where there is little cooling air flow. In addition, high-temperature air that has just passed through the axial gap 50 flows into the outer peripheral space 51. This makes it easier to secure a large temperature difference between the heat-absorbing fins 71 and the air, thus increasing the heat transfer coefficient.

[0057] The heat-absorbing fins 71 are provided on the fin casing 70. Therefore, by replacing the fin casing 70 on which the heat-absorbing fins 71 are formed, the installation configuration, such as the shape and number of heat-absorbing fins 71, can be easily changed.

[0058] The heat-absorbing fins 71 are formed in an annular shape, continuously along the circumferential direction CD of the rotor 30. Therefore, compared to cases where the fins are formed along the axial direction AD, they are less likely to obstruct the flow of wall-surface air inside the rotating electric machine 100. Consequently, it is easier to allow the wall-surface air to flow smoothly and efficiently transfer heat. In addition, the heat transfer area can be increased over the entire circumference of the inner surface of the fin casing 70.

[0059] <Second Embodiment> This embodiment is a modification based on the preceding embodiment. In this embodiment, the shape of the heat-absorbing fin 271 differs from that of the above-described embodiment.

[0060] In Figure 5, the heat-absorbing fin 271 is helical in a continuous manner in the circumferential direction CD. Therefore, in the cross-sectional view obtained by cutting the rotating electric machine 100 along the rotation axis Cm of the rotor 30, the axial distance AD ​​from the end plate 45 to the heat-absorbing fin 271 is different. The heat-absorbing fin 271 has a gap where the connecting portion 25 and other parts are arranged, but as a whole it is substantially helical. The heat-absorbing fin 271 may also be formed in a helical shape without gaps.

[0061] The amount of protrusion of the heat-absorbing fin 271 is greater than the thickness of the base of the fin casing 70. The amount of protrusion of the heat-absorbing fin 271 is greater than the gap length of the axial gap 50. The amount of protrusion of the heat-absorbing fin 271 is less than the amount of protrusion of the heat-dissipating fin 42 in the radial direction RD. The heat-absorbing fin 271 provides an example of a heat transfer promoting section.

[0062] The flow of cooling air near the heat absorption fins 271 will now be explained. In Figure 6, a portion of the wall flow flowing in the circumferential direction CD flows between adjacent heat absorption fins 271 in the axial direction AD. This wall flow flowing between the heat absorption fins 271 is guided by the helically formed heat absorption fins 271 and has a velocity component that approaches the end plate 45. In other words, the wall flow flowing between the heat absorption fins 271 can move towards the end plate 45 without crossing over the heat absorption fins 271 in the axial direction.

[0063] Both the wall flow and the circulating flow contained in the cooling air have velocity components that move toward the end plate 45 in the external space. As a result, unintended turbulence in the cooling air near the heat absorption fin 271 is suppressed, and the cooling air flows smoothly.

[0064] The effects of the above-described embodiment will now be explained. According to the above-described embodiment, the heat absorption fin 271 is formed in a helical shape that is continuous with respect to the circumferential direction CD. As a result, the air flowing through the outer peripheral space 51, guided by the helical heat absorption fin 271, has a velocity component that approaches the end plate 45. Therefore, the flow of cooling air in the outer peripheral space 51 is made smoother, and the heat transfer coefficient from the air inside the housing 40 to the housing 40 is easily increased.

[0065] <Third Embodiment> This embodiment is a modification based on the preceding embodiment. In this embodiment, the shape of the heat-absorbing fin 371 differs from that of the above-described embodiment.

[0066] In Figure 7, the heat-absorbing fins 371 are plate-shaped and extend along the circumferential direction CD. Four heat-absorbing fins 371 arranged at equal intervals along the axial direction AD form the first fin group 371a. Similarly, four heat-absorbing fins 371 arranged at equal intervals along the axial direction AD form the second fin group 371b.

[0067] The first fin group 371a and the second fin group 371b are arranged side by side in the circumferential direction CD. The heat-absorbing fins 371 of the second fin group 371b are positioned in the axial direction AD between adjacent heat-absorbing fins 371 that form part of the first fin group 371a. In other words, the heat-absorbing fins 371 of the first fin group 371a and the heat-absorbing fins 371 of the second fin group 371b are positioned so as not to overlap each other in either the circumferential direction CD or the axial direction AD. To put it another way, the heat-absorbing fins 371 can be said to be arranged in a staggered pattern.

[0068] The amount of protrusion of the heat-absorbing fin 371 is greater than the thickness of the base of the fin casing 70. The amount of protrusion of the heat-absorbing fin 371 is greater than the gap length of the axial gap 50. The amount of protrusion of the heat-absorbing fin 371 is less than the amount of protrusion of the heat-dissipating fin 42 in the radial direction RD. The heat-absorbing fin 371 provides an example of a heat transfer promoting section.

[0069] The flow of cooling air near the heat-absorbing fins 371 will now be described. A portion of the wall flow flowing in the circumferential direction CD is guided along the first fin group 371a in the circumferential direction CD. The wall flow that has passed through the first fin group 371a flows in the circumferential direction CD and reaches the upstream end of the heat-absorbing fins 371 that make up the second fin group 371b. As a result, the flow is divided into a flow along the drive-side surface of the heat-absorbing fins 371 and a flow along the rear-side surface of the heat-absorbing fins 371.

[0070] Since the cooling air contains a circulating flow, the cooling air has a velocity component that approaches the drive frame 45d due to the circulating flow. Therefore, the wall flow that strikes the end of the heat-absorbing fin 371 is more likely to flow towards the drive-side surface of the heat-absorbing fin 371 than towards the rear-side surface. The same is true for the cooling air flow near the heat-absorbing fin 371 formed in the rear-side fin casing 70r located at the rear. That is, due to the influence of the circulating flow in the outer peripheral space 51 which has a velocity component that approaches the rear frame 45r, the wall flow that strikes the upstream end of the heat-absorbing fin 371 forming the second fin group 371b is more likely to flow towards the rear-side surface of the heat-absorbing fin 371 than towards the drive-side surface.

[0071] The effects of the above-described embodiment will now be explained. According to the above-described embodiment, the heat-absorbing fins 371 of the second fin group 371b are positioned between adjacent heat-absorbing fins 371 of the first fin group 371a in the axial direction AD. As a result, the air guided by the first fin group 371a can reach the upstream end of the heat-absorbing fins 371 of the second fin group 371b and flow closer to the end plate 45. Therefore, the heat-absorbing fins 371 are less likely to obstruct the flow of cooling air in the outer peripheral space 51 in the direction toward the end plate 45. Thus, it is easier to increase the flow velocity of the cooling air and improve the heat transfer coefficient from the air inside the housing 40 to the housing 40.

[0072] <Fourth Embodiment> This embodiment is a modification based on the preceding embodiment. In this embodiment, the outer peripheral wall 41 of the electric machine in the outer peripheral space 51 is provided with a groove 443.

[0073] In Figure 8, grooves 443 are formed in the portion of the electrical outer wall 41 facing the outer space 51. Four grooves 443 are formed in the outer space 51 on the drive side. On the other hand, three grooves 443 are formed in the outer space 51 on the rear side.

[0074] The groove 443 is rectangular in shape and is provided in an annular manner on the inside of the outer wall 41 of the electric machine, continuously in the circumferential direction CD. The groove 443 comprises a drive-side portion that forms the side closer to the drive side, a rear-side portion that forms the side closer to the rear side, and a bottom portion that connects the drive-side portion and the rear-side portion. The depth of the groove 443 is greater than the distance between adjacent grooves 443. The depth of the grooves 443 is the same for multiple grooves 443. The form of the groove 443 is not limited to the example described above. For example, the shape of the groove may be semicircular or triangular. Alternatively, the groove may be formed in a helical shape. Alternatively, the depths of the grooves may be different from each other. The groove 443 provides an example of a heat transfer promoting portion.

[0075] The flow of cooling air near the groove 443 will now be explained. A portion of the wall flow that flows in the circumferential direction CD is guided by the groove 443 and flows through the groove 443. The air flowing through the groove 443 transfers heat to the outer wall 41 of the electric machine on three surfaces: the drive-side surface, the rear-side surface, and the bottom surface that form the groove 443. In other words, the heat transfer area is increased by the formation of the groove 443 compared to when the groove 443 is not formed.

[0076] The effects of the above-described embodiment will now be explained. According to the above-described embodiment, a groove 443 is provided on the inside of the outer peripheral wall 41 of the electric machine. Therefore, compared to the case where the groove 443 is not provided, the heat transfer area from the air flowing in the outer peripheral space 51 to the housing 40 can be increased. Consequently, it is easier to increase the heat transfer coefficient from the air inside the housing 40 to the housing 40.

[0077] The groove 443 is formed in the outer wall 41 of the electric machine. Therefore, compared to a configuration that uses additional parts different from the outer wall 41 of the electric machine to increase the heat transfer area, it is easier to reduce the number of parts and improve the manufacturability of the rotating electric machine 100.

[0078] <Fifth Embodiment> This embodiment is a modification based on the preceding embodiment. In this embodiment, a vortex generator 571 is provided in the outer peripheral space 51.

[0079] In Figure 9, a vortex generator 571 is formed inside the fin casing 70. The vortex generator 571 is a projection formed on the fin casing 70. The vortex generator 571 has a triangular pyramidal shape. One surface of the vortex generator 571 acts as resistance to the cooling air flowing in the circumferential direction CD, creating areas of high and low flow velocity and thereby generating a longitudinal vortex. A longitudinal vortex is a spiral-shaped flow of air. Multiple vortex generators 571 are provided in the fin casing 70, arranged in both the axial and circumferential directions. The multiple vortex generators 571 provided in the fin casing 70 are all identical in shape.

[0080] The configuration of the vortex generator 571 is not limited to the examples described above. For example, the vortex generator 571 may be a square pyramidal member or a plate-shaped member inclined with respect to the flow of CD in the circumferential direction. Alternatively, vortex generators 571 of different shapes may be provided.

[0081] The amount of protrusion of the vortex generator 571 is greater than the thickness of the base of the fin casing 70. The amount of protrusion of the vortex generator 571 is greater than the gap length of the axial gap 50. The amount of protrusion of the vortex generator 571 is less than the amount of protrusion of the heat dissipation fin 42 in the radial direction RD. The vortex generator 571 provides an example of a heat transfer promoting section.

[0082] The flow of cooling air near the vortex generator 571 will now be explained. The air that has passed through the axial gap 50 proceeds into the outer peripheral space 51, where it collides with the vortex generator 571. A portion of the cooling air that collides with the vortex generator 571 generates longitudinal vortices downstream of the vortex generator 571 due to the difference in flow velocity between it and the surrounding cooling air. These longitudinal vortices stir the cooling air, creating turbulence in the cooling air flow. The cooling air that has become turbulent downstream of the vortex generator 571 is again subjected to the generation of longitudinal vortices by another vortex generator 571 arranged in the circumferential direction, resulting in turbulence once more. In this way, the cooling air that has passed through the axial gap 50 and flowed into the outer peripheral space 51 flows while repeatedly generating turbulence due to multiple vortex generators 571.

[0083] The effects of the above-described embodiment will now be explained. According to the above-described embodiment, a vortex generator 571 is provided that generates longitudinal vortices in the air passing through the axial gap 50. Therefore, turbulence is generated in the cooling air flowing through the outer peripheral space 51, making it easier to increase the heat transfer coefficient from the air inside the housing 40 to the housing 40.

[0084] Furthermore, compared to a configuration without the vortex generator 571, the heat transfer area from the air flowing in the outer peripheral space 51 to the housing 40 can be increased. This makes it easier to increase the heat transfer coefficient from the air inside the housing 40 to the housing 40.

[0085] The vortex generator 571 is provided on the fin casing 70. Therefore, by replacing the fin casing 70 on which the vortex generator 571 is formed, the shape, number, and other installation configurations of the vortex generator 571 can be easily changed.

[0086] <Sixth Embodiment> This embodiment is a modification based on the preceding embodiment. In this embodiment, the vortex generator 647 is formed integrally with the end plate 45.

[0087] In Figure 10, a drive-side projection 646d is formed along the axial direction from the inside of the drive frame 45d. The drive-side projection 646d protrudes into the outer peripheral space 51 when the drive frame 45d is fitted and mounted on the outer peripheral wall 41 of the electric machine. The drive-side projection 646d extends axially to a position where the magnet 31 of the drive-side rotor 30d and the drive-side projection 646d overlap radially. A drive-side vortex generator 647d is formed on the drive-side projection 646d.

[0088] A rear projection 646r is formed along the axial direction from the inside of the rear frame 45r. The rear projection 646r protrudes into the outer peripheral space 51 when the rear frame 45r is fitted and fixed into the outer peripheral wall 41 of the electric motor. The rear projection 646r extends axially to a position where the magnet 31 of the rear rotor 30r and the rear projection 646r overlap radially. A rear vortex generator 647r is formed on the rear projection 646r.

[0089] The protrusion 646 includes a drive-side protrusion 646d and a rear-side protrusion 646r. The vortex generator 647 includes a drive-side vortex generator 647d and a rear-side vortex generator 647r.

[0090] The protrusions 646 are plate-shaped and extend along the circumferential direction CD. Multiple protrusions 646 are provided on the end plate 45 along the circumferential direction CD. The multiple protrusions 646 arranged in the circumferential direction are spaced apart from each other along the circumferential direction CD. Therefore, in the outer peripheral space 51, the space located inside the radial direction RD relative to the protrusions 646 and the space located outside the radial direction RD relative to the protrusions 646 are in communication.

[0091] The vortex generator 647 is triangular pyramidal in shape. The vortex generator 647 generates longitudinal vortices by creating areas of high and low flow velocity, with one surface acting as resistance to the cooling air flowing in the circumferential direction CD. The vortex generator 647 is provided on both the inner surface, which is the surface of the protrusion 646 facing the rotor 30, and the outer surface, which is the surface of the protrusion 646 facing the outer wall 41 of the electric motor. The multiple vortex generators 647 provided on the protrusion 646 are all the same shape.

[0092] The configuration of the vortex generator 647 is not limited to the examples described above. For example, the vortex generator 647 may be a square pyramidal member or a plate-shaped member inclined with respect to the flow of CD in the circumferential direction. Alternatively, vortex generators 647 of different shapes may be provided.

[0093] The amount of protrusion of the vortex generator 647 is smaller than the amount of protrusion of the heat dissipation fin 42 in the radial direction RD. The vortex generator 647 provides an example of a heat transfer promotion section.

[0094] The flow of cooling air near the vortex generator 647 will now be explained. The air that has passed through the axial gap 50 proceeds into the outer peripheral space 51, where it collides with the vortex generator 647. A portion of the cooling air that collides with the vortex generator 647 generates longitudinal vortices downstream of the vortex generator 647 due to the difference in flow velocity with the surrounding cooling air. These longitudinal vortices stir the cooling air, creating turbulence in the cooling air flow. The cooling air that has become turbulent downstream of the vortex generator 647 is again subjected to the generation of longitudinal vortices by another vortex generator 647 arranged in the circumferential direction, resulting in turbulence once more. In this way, the cooling air that has passed through the axial gap 50 and flowed into the outer peripheral space 51 flows while repeatedly generating turbulence due to multiple vortex generators 647.

[0095] The effects of the above-described embodiment will now be explained. According to the above-described embodiment, the vortex generator 647 is provided on the protruding portion 646. Therefore, compared to a configuration that uses additional parts different from the end plate 45 to generate turbulence in the cooling air flowing through the outer peripheral space 51 and to increase the heat transfer area, it is easier to reduce the number of parts and improve the manufacturability of the rotating electric machine 100.

[0096] <Seventh Embodiment> This embodiment is a modification based on the preceding embodiment. In this embodiment, the vortex generator 726 is provided integrally with the connecting portion 25.

[0097] In Figure 11, a vortex generator 726 is formed in the portion of the connection 25 located in the outer peripheral space 51. The vortex generator 726 is a projection formed in the connection 25 so as to protrude inward in the radial direction RD. The vortex generator 726 has a triangular pyramidal shape. One surface of the vortex generator 726 acts as resistance to the cooling air flowing in the circumferential direction CD, creating areas of high and low flow velocity and thereby generating longitudinal vortices.

[0098] Multiple vortex generators 726 are provided in a single connection section 25, arranged in the axial direction. In the rotating electric machine 100, if multiple connection sections 25 are provided in a line along the circumferential direction CD, then multiple vortex generators 726 will also be provided in a line along the circumferential direction CD. The multiple vortex generators 726 are all identical in shape.

[0099] The configuration of the vortex generator 726 is not limited to the examples described above. For example, the vortex generator 726 may be a square pyramidal member or a plate-shaped member inclined with respect to the flow of CD in the circumferential direction. Alternatively, vortex generators 726 of different shapes may be provided.

[0100] The amount of protrusion of the vortex generator 726 is greater than the thickness of the base of the connection portion 25. The amount of protrusion of the vortex generator 726 is greater than the gap length of the axial gap 50. The amount of protrusion of the vortex generator 726 is less than the amount of protrusion of the heat dissipation fin 42 in the radial direction RD. The vortex generator 726 provides an example of a heat transfer promoting portion.

[0101] The flow of cooling air near the vortex generator 726 will now be explained. The air that has passed through the axial gap 50 proceeds into the outer peripheral space 51, where it collides with the vortex generator 726. A portion of the cooling air that collides with the vortex generator 726 generates longitudinal vortices downstream of the vortex generator 726 due to the difference in flow velocity between it and the surrounding cooling air. These longitudinal vortices stir the cooling air, creating turbulence in the cooling air flow. In this way, the cooling air that has passed through the axial gap 50 and flowed into the outer peripheral space 51 flows while generating turbulence due to the vortex generator 726.

[0102] The effects of the above-described embodiment will now be explained. According to the above-described embodiment, the vortex generator 726 is provided in the connection part 25. Therefore, compared to a configuration in which additional parts different from the connection part 25 are used to generate turbulence in the cooling air flowing in the outer peripheral space 51 and to increase the heat transfer area, it is easier to reduce the number of parts and improve the manufacturability of the rotating electric machine 100.

[0103] <Other Embodiments> The disclosures in this specification and drawings are not limited to the exemplary embodiments. The disclosures include the exemplary embodiments and variations thereof by those skilled in the art. For example, the disclosures are not limited to combinations of parts and / or elements shown in the embodiments. The disclosures are implementable in a variety of combinations. The disclosures may have additional parts that can be added to the embodiments. The disclosures include those in which parts and / or elements of the embodiments have been omitted. The disclosures include substitutions or combinations of parts and / or elements between one embodiment and another. The scope of the disclosed technical areas is not limited to the descriptions of the embodiments. Some of the scope of the disclosed technical areas are indicated by the claims and should be understood to include all modifications within the meaning and scope equivalent to the claims.

[0104] The disclosures in the specification and drawings are not limited by the claims. The disclosures in the specification and drawings encompass the technical ideas described in the claims and extend to a wider and more diverse range of technical ideas than those described in the claims. Therefore, a variety of technical ideas can be extracted from the disclosures in the specification and drawings without being bound by the claims. [Explanation of symbols]

[0105] 10 Shaft, 20 Stator, 21 Coil section, 22 Stator core, 25 Connection section, 29 Connection terminal, 30 Rotor, 31 Magnet, 35 Fixing member, 36 Magnet holder, 37 Support column, 38 Support column fixing section, 40 Housing, 41 Electrical outer wall, 42 Heat dissipation fin, 45 End plate, 50 Axial gap, 51 Outer space, 52 Inner space, 53 Frame space, 54 Space between support columns, 70 Fin casing, 71 Heat absorption fin, 100 Rotating electric machine, 271 Heat absorption fin, 371 Heat absorption fin, 371a First fin group, 371b Second fin group, 443 Groove section, 571 Vortex generator, 646 Protrusion, 647 Vortex generator, 726 vortex generator

Claims

1. A rotating electric machine (100) that is driven by the supply of electricity, Stator (20) and, A rotor (30) rotates around a rotation axis and is positioned with an axial gap (50) between it and the stator in the axial direction from which the rotation axis extends, The rotor comprises a magnet (31), a magnet holder (36) that holds the magnet, and a plurality of support columns (37) that support the magnet holder and form a flow path through which air flows from the inner circumference to the outer circumference. The aforementioned rotating electric machine comprises a housing (40) that houses the stator and the rotor inside and has a heat dissipation promoting portion (42) on its outer surface, A rotating electric machine comprising heat transfer promoting units (71, 271, 371, 443, 571, 647, 726) that promote heat transfer from the air passing through the axial gap to the housing.

2. The housing comprises a cylindrical electrical outer wall (41) having the heat dissipation promotion portion, and an end plate (45) attached to the open end of the electrical outer wall. The rotating electric machine according to claim 1, wherein the heat transfer promoting portion is located in the outer peripheral space (51) between the rotor and the outer peripheral wall of the electric machine.

3. The rotor and the outer wall of the electric motor are provided with a fin casing (70) that is in contact with the inside of the outer wall of the electric motor, The rotating electric machine according to claim 2, wherein the heat transfer promoting section is a heat-absorbing fin (71, 271, 371) provided on the fin casing.

4. The rotating electric machine according to claim 3, wherein the heat-absorbing fins are formed in an annular shape continuously in the circumferential direction of the rotor.

5. The rotating electric machine according to claim 3, wherein the heat-absorbing fins are formed in a helical shape continuously in the circumferential direction of the rotor.

6. The heat-absorbing fin comprises a first fin group (371a) having a plurality of heat-absorbing fins arranged in line along the axial direction, and a second fin group (371b) having a plurality of heat-absorbing fins arranged in line along the axial direction. The first fin group and the second fin group are arranged in the circumferential direction of the rotor, The rotating electric machine according to claim 3, wherein the heat-absorbing fins of the second fin group are provided positioned between adjacent heat-absorbing fins of the first fin group in the axial direction.

7. The rotating electric machine according to claim 2, wherein the heat transfer promoting portion is a groove (443) provided on the inside of the outer wall of the electric machine.

8. The rotating electric machine according to claim 2, wherein the heat transfer promoting part is a vortex generating body (571, 647, 726) that generates longitudinal vortices in the air passing through the axial gap.

9. The rotor and the outer wall of the electric motor are provided with a fin casing (70) that is in contact with the inside of the outer wall of the electric motor, The rotating electric machine according to claim 8, wherein the vortex generator is provided in the fin casing.

10. The end plate is provided with a protruding portion (646) that protrudes from the end plate in the axial direction into the outer peripheral space, The rotating electric machine according to claim 8, wherein the vortex generator is provided on the protruding portion.

11. The stator has a stator core (22) and a coil portion (21) wound around the stator core. The housing includes a connection part (25) for electrically connecting the coil parts to each other or the coil parts to a connection terminal (29) provided on the outside of the housing. The rotating electric machine according to claim 8, wherein the vortex generator is provided at the connection portion.

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