Drive device

Abstract

An EPU (50) has an inverter housing (90). The inverter housing (90) has an inverter housing body (91) and inverter fins (92). The outer surface of the inverter housing body (91) includes an inverter outer circumferential surface (910) and an inverter upstream surface (911). The inverter fins (92) have parallel fin parts (111) and cross fin parts (121). The parallel fin parts (111) extend from the inverter outer circumferential surface (910) toward the outer circumference side. The cross fin parts (121) extend from the parallel fin parts (111) toward one side in the circumferential direction (CD). The parallel fin parts (111) and the cross fin parts (121) extend along the inverter outer circumferential surface (910) in the axis direction (AD).

Description

Drive unit CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is based on Patent Application No. 2023-137529 filed in Japan on August 25, 2023, and the contents of the original application are incorporated by reference in their entirety.

[0002] The disclosure herein relates to a drive device.

[0003] Patent Document 1 describes a heat sink for an electrical device. The heat sink has a plurality of heat dissipation fins provided on one side of a heat dissipation substrate. In this heat sink, an air flow path is formed between two adjacent heat dissipation fins.

[0004] Japanese Patent Application Laid-Open No. 2001-111265

[0005] It is conceivable that the heat sink of Patent Document 1 described above may be applied to the housing of a drive device. For example, a configuration is conceivable in which heat dissipation fins are provided on the outer peripheral surface of the housing so as to extend in the axial direction of the housing. However, in this configuration, when gas such as air flows axially toward the housing, the gas tends to avoid the housing and expand toward the outer peripheral side. In this case, there is a concern that the gas flowing along the heat dissipation fins may be insufficient, resulting in an insufficient heat dissipation effect of the gas on the drive device.

[0006] One object of the present disclosure is to provide a drive device that can improve the heat dissipation effect of the housing.

[0007] The multiple aspects disclosed in this specification employ different technical means to achieve their respective objectives. Furthermore, the reference symbols in parentheses in the claims and this section are merely examples showing the correspondence between specific means described in the embodiments below as one aspect, and do not limit the technical scope.

[0008] In order to achieve the above object, the first aspect disclosed is a drive device that is driven by electricity and includes: a heat generating portion that generates heat when current is applied; a housing having an outer circumferential surface extending in the axial direction and accommodating the heat generating portion; and outer circumferential fins that extend from the outer circumferential surface of the housing toward the outer periphery, are arranged in multiple rows circumferentially of the housing, and release heat from the heat generating portion to the outside of the housing, wherein the outer circumferential fins include an outer circumferential fin portion that extends in the axial direction along the outer circumferential surface of the housing; an outer circumferential extension portion that extends from the outer circumferential fin portion in the axial direction beyond the outer circumferential surface of the housing; and an outer circumferential restriction portion that is included in at least one of the outer circumferential fin portion and the outer circumferential extension portion and restricts gas from flowing between two circumferentially adjacent outer circumferential fins toward the outer periphery.

[0009] According to the first aspect, the outer peripheral fin has an outer peripheral extension extending from the outer peripheral fin portion in the axial direction beyond the outer peripheral surface of the housing. With this configuration, when gas, such as air, flowing axially toward the housing avoids the housing and expands toward the outer periphery, it easily flows along the outer peripheral extension. Therefore, the heat dissipation effect of the outer peripheral fin can be enhanced by the outer peripheral extension. Furthermore, between two circumferentially adjacent outer peripheral fins, the outer peripheral limiting portion restricts the gas from passing through the outer peripheral fin toward the outer periphery. Between two circumferentially adjacent outer peripheral fins, the gas flowing toward the outer periphery is guided by the outer peripheral limiting portion so that it flows axially along the outer peripheral surface of the housing. Therefore, the amount of gas flowing along the outer peripheral fin portion is likely to increase. Therefore, the heat dissipation effect of the outer peripheral fin portion can be enhanced by the outer peripheral limiting portion. As described above, the heat dissipation effect of the housing in the drive device can be enhanced by the outer peripheral fin.

[0010] A second aspect is a drive device that is driven by electricity and includes: a heat-generating portion that generates heat when current is applied; a housing having a housing outer peripheral surface extending in the axial direction and accommodating the heat-generating portion; outer peripheral fins that extend from the housing outer peripheral surface toward the outer peripheral side and are arranged in a plurality in the circumferential direction of the housing and release heat from the heat-generating portion to the outside of the housing; and an outer peripheral duct that is provided on the outer peripheral side of the housing outer peripheral surface via the outer peripheral fins so as to cover the housing outer peripheral surface from the outer peripheral side, wherein the outer peripheral fin has an outer peripheral fin portion that extends in the axial direction along the housing outer peripheral surface, and an outer peripheral extension portion that extends from the outer peripheral fin portion in the axial direction beyond the housing outer peripheral surface, and the outer peripheral duct has a duct restricting portion that restricts gas from flowing between two circumferentially adjacent outer peripheral fins toward the outer peripheral side, and extends in the axial direction so as to span the outer peripheral fin portion and the outer peripheral extension portion.

[0011] According to the second aspect, as with the first aspect, the heat dissipation effect of the outer peripheral fins can be enhanced by the outer peripheral extension. Moreover, between two circumferentially adjacent outer peripheral fins, the duct restricting portion restricts the flow of gas passing through the outer peripheral fins toward the outer periphery. Between two circumferentially adjacent outer peripheral fins, the duct restricting portion guides the gas flowing toward the outer periphery to flow in the axial direction along the outer circumferential surface of the housing. This makes it easier for gas to flow along the outer peripheral fin portion, and the heat dissipation effect of the outer peripheral fin portion can be enhanced by the duct restricting portion. As described above, the heat dissipation effect of the housing in the drive device can be enhanced by the outer peripheral fins and the outer peripheral duct.

[0012] A third aspect is a drive device that is driven by electricity and includes: a heat-generating portion that generates heat when current is applied; a housing that accommodates the heat-generating portion, the housing having a housing outer peripheral surface extending in the axial direction and a housing cover surface that extends so as to intersect with the housing outer peripheral surface and cover the heat-generating portion from the axial direction; and axial fins that extend in the axial direction from the housing cover surface, are arranged in multiple rows circumferentially of the housing, and release heat from the heat-generating portion to the outside of the housing, wherein the axial fins have: a axial fin portion that extends toward the outer periphery along the housing cover surface; a axial extension portion that extends from the axial fin portion outer than the housing outer peripheral surface; and a axial restricting portion that is included in the axial extension portion and restricts the flow of gas passing between two circumferentially adjacent axial fins toward the outer periphery.

[0013] According to the third aspect, in the shaft fin, the shaft extension portion extends from the shaft fin portion outward beyond the housing outer peripheral surface. With this configuration, when gas, such as air, flowing in the axial direction toward the housing expands toward the outer peripheral side, avoiding the housing, it easily flows along the shaft fin portion and the shaft extension portion. Therefore, the heat dissipation effect of the shaft fin can be enhanced by the shaft extension portion. Furthermore, between two circumferentially adjacent shaft fins, the axial limiting portion restricts the gas from passing through the shaft fin toward the outer peripheral side. Between two circumferentially adjacent shaft fins, the gas flowing toward the outer peripheral side is guided by the axial limiting portion so that it flows axially along the housing outer peripheral surface. Therefore, the amount of gas flowing along the housing outer peripheral surface is likely to increase. Therefore, the heat dissipation effect of the housing outer peripheral surface can be enhanced by the axial limiting portion. As described above, the heat dissipation effect of the housing in the drive device can be enhanced by the shaft fins.

[0014] A fourth aspect is a drive device driven by electricity, comprising: a heat-generating portion that generates heat when current is applied; a housing that accommodates the heat-generating portion, the housing having a housing outer peripheral surface extending in the axial direction and a housing cover surface that extends so as to intersect with the housing outer peripheral surface and cover the heat-generating portion from the axial direction; axial fins that extend axially from the housing cover surface, are arranged in a plurality of rows circumferentially of the housing, and release heat from the heat-generating portion to the outside of the housing; and an outer circumferential duct that is provided on the outer circumferential side of the housing outer peripheral surface and the axial fins so as to cover the housing outer peripheral surface and the axial fins from the outer circumferential side, wherein the axial fin has an axial fin portion that extends toward the outer circumferential side along the housing cover surface, and an axial extension portion that extends from the axial fin portion outer circumferentially of the housing; and the outer circumferential duct has a duct restricting portion that restricts gas from flowing between two circumferentially adjacent axial fins toward the outer circumferential side, and extends in the axial direction so as to span the axial fin portion and the axial extension portion.

[0015] According to the fourth aspect, as with the third aspect, the heat dissipation effect of the axial fins can be enhanced by the axial extension portion. Moreover, between two circumferentially adjacent axial fins, the duct restricting portion restricts the flow of gas passing through the axial fins toward the outer periphery. Between two circumferentially adjacent axial fins, the duct restricting portion guides the gas flowing toward the outer periphery so that it flows in the axial direction along the housing outer periphery surface. This makes it easier for the gas flowing along the housing outer periphery surface to increase, and the heat dissipation effect of the housing outer periphery surface can be enhanced by the duct restricting portion. As described above, the heat dissipation effect of the housing in the drive device can be enhanced by the axial fins and the outer periphery duct.

[0016] 16 is a diagram showing the configuration of an eVTOL in a first embodiment. A diagram showing the electrical configuration of a propulsion system. A side view of a propulsion device. A plan view of an inverter device. A cross-sectional view along line V-V in FIG. 3. A cross-sectional view along line VI-VI in FIG. 4, showing a longitudinal cross-sectional view of the inverter device. An enlarged view of FIG. 6, showing a longitudinal cross-sectional view of the periphery of inverter fins in the inverter device. A longitudinal cross-sectional view of the periphery of inverter fins in the inverter device in a second embodiment. A longitudinal cross-sectional view of an inverter device in a third embodiment. A plan view of an inverter device. A longitudinal cross-sectional view of the periphery of inverter fins in the inverter device. A longitudinal cross-sectional view of an inverter device in a fourth embodiment. A longitudinal cross-sectional view of the periphery of inverter fins in the inverter device in a fifth embodiment. A plan view of an inverter device in a sixth embodiment. A longitudinal cross-sectional view of the periphery of inverter fins in the inverter device. A plan view of an inverter device in a seventh embodiment. A cross-sectional view along line XVII-XVII in FIG. 16, showing a longitudinal cross-sectional view of the periphery of inverter fins in the inverter device. A plan view of the periphery of cross fins in the inverter device in an eighth embodiment. A diagram for explaining the relationship between opening ratio and heat dissipation performance. A plan view of an inverter device in a ninth embodiment. A cross-sectional view taken along line XXI-XXI in Figure 20. A longitudinal cross-sectional view of an inverter device according to a tenth embodiment. A plan view of the inverter device. A cross-sectional view taken along line XXIV-XXIV in Figure 22. A perspective view of an outer periphery duct. A longitudinal cross-sectional view of an inverter device according to an eleventh embodiment. A plan view of the inverter device. A cross-sectional view taken along line XXVIII-XXVIII in Figure 26.

[0017] Hereinafter, several embodiments for carrying out the present disclosure will be described with reference to the drawings. In each embodiment, parts corresponding to matters described in the preceding embodiment will be assigned the same reference numerals, and duplicate descriptions may be omitted. In each embodiment, when only a part of the configuration is described, other previously described embodiments may be applied to the other parts of the configuration. In addition to combinations of parts that are specifically specified as being combinable in each embodiment, it is also possible to partially combine embodiments even if not specified, as long as there is no particular problem with the combination.

[0018] First Embodiment The eVTOL 10 shown in FIG. 1 is an electric vertical take-off and landing aircraft. An electric vertical take-off and landing aircraft is an electric vertical take-off and landing aircraft that is capable of vertical take-off and landing. eVTOL is an abbreviation for electric Vertical Take-Off and Landing aircraft. The eVTOL 10 is an electric air vehicle that flies in the atmosphere and is sometimes referred to as an electric air vehicle. The eVTOL 10 is also an electric aircraft and is sometimes referred to as an electric aircraft. The eVTOL 10 is a manned air vehicle that carries a crew member. The crew member of the eVTOL 10 includes a pilot who operates or drives the aircraft.

[0019] The eVTOL 10 has an airframe 11 and a propeller 20. The airframe 11 has an airframe main body 12 and wings 13. The airframe main body 12 is the fuselage of the airframe 11 and has a shape that extends, for example, from front to back. The airframe main body 12 has a crew cabin 14 for crew members to ride in. The wings 13 extend from the airframe main body 12 and multiple wings 13 are provided on the airframe main body 12. The wings 13 are fixed wings. The multiple wings 13 include main wings, a tail, and the like.

[0020] The eVTOL 10 has a cabin. The cabin is provided inside the eVTOL 10. For example, the cabin is the internal space of the aircraft body 12 and is formed by the aircraft body 12. The cabin can be a crew cabin 14 or a cargo bay. The crew cabin 14 can be a passenger cabin or a pilot cabin. The crew cabin 14 is provided with seats for crew members to sit in. The crew cabin 14 does not have to be occupied by crew members, and may instead house cargo.

[0021] A plurality of propellers 20 are provided on the airframe 11. The eVTOL 10 is a multicopter having at least three propellers 20. For example, at least six propellers 20 are provided on the airframe 11. The propellers 20 are provided on each of the airframe body 12 and the wings 13. The propellers 20 rotate around a propeller axis. The propeller axis is, for example, the center line of the propeller 20. The propellers 20 can generate thrust and lift for the eVTOL 10. The propellers 20 are sometimes referred to as rotors or rotating blades.

[0022] The eVTOL 10 has multiple propellers 20, which makes it easier to maintain aircraft balance. Even if the propeller output of one propeller 20 unintentionally decreases, the eVTOL 10 can continue flight using the remaining propellers 20. Propeller output includes the rotation speed and torque of the propellers 20.

[0023] The propeller 20 has blades, a boss, and a propeller shaft. A plurality of blades are arranged in the circumferential direction of the propeller axis. The boss connects the plurality of blades. The propeller shaft is the rotation axis of the propeller 20 and extends from the boss along the propeller axis.

[0024] Flight modes of the eVTOL 10 include vertical takeoff, vertical landing, cruise, hovering, etc. Flight modes are sometimes referred to as flight modes. In vertical takeoff, the eVTOL 10 can take off without running. In vertical takeoff, the eVTOL 10 may ascend vertically or may ascend diagonally upward. In vertical landing, the eVTOL 10 can land without running. In vertical landing, the eVTOL 10 may descend vertically or may descend diagonally downward.

[0025] Cruising is sometimes referred to as level flight. In cruising, the eVTOL 10 may fly horizontally without moving vertically, or may fly horizontally while moving vertically. Hovering is sometimes referred to as stationary flight. In hovering, the eVTOL 10 may fly as if stationary at a predetermined position in the air, or the eVTOL 10 may deviate vertically or horizontally from the predetermined position.

[0026] The flight modes of the eVTOL 10 also include lift. In lift, the eVTOL 10 moves up and down. As a lift, the eVTOL 10 may ascend diagonally upward or descend diagonally downward. The eVTOL 10 takes off vertically by lifting upward. The eVTOL 10 lands vertically by lifting downward.

[0027] The eVTOL 10 is a tilt rotor aircraft. The eVTOL 10 has an adjustable tilt angle for the propeller 20. The eVTOL 10 can have one propeller 20 function as both a lift propeller and a cruise propeller. For example, when the eVTOL 10 lifts, the tilt angle is adjusted so that the propeller 20 functions as a lift rotor. When the eVTOL 10 cruises, the tilt angle is adjusted so that the propeller 20 functions as a cruise rotor. Note that the eVTOL 10 does not have to be a tilt rotor aircraft. For example, the eVTOL 10 may have separate propellers 20 for lift and cruise.

[0028] The propulsion system 30 shown in Figure 2 is mounted on the eVTOL 10. The propulsion system 30 is a system that drives the eVTOL 10 to propel it forward. The propulsion system 30 has a battery 31 and an EPU 50. The battery 31 and the EPU 50 are mounted on the EPU 50. The propulsion system 30 also has a flight control device (not shown). The flight control device performs flight control to fly the eVTOL 10. The flight control involves control of the propulsion system 30 and the EPU 50.

[0029] The battery 31 is electrically connected to the EPU 50. The battery 31 is a power supply unit that supplies power to the EPU 50 and corresponds to a power supply unit. The battery 31 is a DC voltage source that applies a DC voltage to the EPU 50. The battery 31 has a rechargeable secondary battery. Examples of such secondary batteries include a lithium ion battery and a nickel-metal hydride battery. The battery 31 is capable of storing power and corresponds to a power storage device. Note that a fuel cell, a generator, or the like may be used as the power supply unit in addition to or instead of the battery 31.

[0030] 1 and 2, the EPU 50 is an electrically powered device and corresponds to a drive device. The EPU 50 drives the propeller 20 to rotate. EPU is an abbreviation for Electric Propulsion Unit. The EPU 50 is sometimes referred to as an electric drive device or an electric drive system. An EPU 50 is provided for each of the multiple propellers 20. The EPUs 50 are arranged on the propellers 20 along the propeller axis. All of the multiple EPUs 50 are fixed to the airframe 11. The EPUs 50 support the propellers 20 so that they can rotate. The EPUs 50 are connected to the propellers 20. The propellers 20 are fixed to the airframe 11 via the EPUs 50.

[0031] As shown in FIG. 1 , the eVTOL 10 has a propulsion device 100. The propulsion device 100 is formed to include a propeller 20 and an EPU 50. The propulsion device 100 is a device for propelling the eVTOL 10. The propulsion device 100 causes the eVTOL 10 to fly by rotating the propeller 20. The eVTOL 10 is also a moving body that moves using the propulsion device 100. A plurality of propulsion devices 100 are provided in the eVTOL 10. One propulsion device 100 includes one propeller 20 and one EPU 50 for driving the propeller 20. Note that only the EPU 50 of the propeller 20 and the EPU 50 may be referred to as the propulsion device 100.

[0032] The EPU 50 has a motor device 60 and an inverter device 80. The motor device 60 has a motor 61 and a motor housing 70. The motor housing 70 is a housing and houses the motor 61. The motor 61 is a multi-phase AC motor. The motor 61 is a multi-phase AC rotating electric machine. The motor 61 is the flight drive source for the eVTOL 10 and functions as an electric motor. The motor 61 is a motor generator. The motor 61 functions as a generator during regeneration. For example, a brushless motor is used as the motor 61.

[0033] Motor 61 enables eVTOL 10 to fly by driving and rotating propeller 20. Motor 61 is a flight motor for flying eVTOL 10. Motor 61 drives and rotates propeller 20 by being powered by battery power. Battery power is power supplied to motor 61 from battery 31.

[0034] As shown in Figure 3, the motor 61 has a motor stator 62, a motor rotor 63, and a motor shaft 64. The motor stator 62 is a stator and is fixed to a motor housing 70. The motor rotor 63 rotates relative to the motor stator 62. Rotation of the motor rotor 63 is sometimes referred to as rotation of the motor 61. The motor shaft 64 rotates together with the motor rotor 63. The motor shaft 64 is rotatably supported by the motor housing 70 or the like. The motor shaft 64 is connected to the propeller 20. In the propulsion device 100, the propeller 20 rotates together with the motor shaft 64.

[0035] The motor 61 is, for example, an axial gap motor. In the motor 61, a motor stator 62 and a motor rotor 63 are arranged in the axial direction AD along the motor axis Cm. The motor 61 is a double-rotor motor. In the motor 61, the two motor rotors 63 are arranged in the axial direction AD via the motor stator 62.

[0036] The motor axis Cm is the center line of the motor 61 and is a virtual line that extends linearly. The motor rotor 63 rotates around the motor axis Cm. The motor axis Cm corresponds to the axis of rotation. The axial direction AD is the direction in which the motor axis Cm extends. With respect to the motor axis Cm, the axial direction AD, the circumferential direction CD, and the radial direction RD are perpendicular to each other. The circumferential direction CD is the direction in which the motor 61 rotates. With respect to the radial direction RD, the outer side is sometimes referred to as the radially outer side or outer circumferential side, and the inner side is sometimes referred to as the radially inner side or inner circumferential side.

[0037] The inverter device 80 drives the motor device 60 by supplying power to the motor device 60. The inverter device 80 is a drive unit for driving the motor 61, and corresponds to a motor drive unit. The inverter device 80 has an inverter unit 170 and an inverter housing 90. The inverter housing 90 is a housing and houses the inverter unit 170. The inverter unit 170 is capable of converting power. The inverter unit 170 converts the power supplied from the battery 31 to the motor 61. The inverter unit 170 is formed in a plate shape overall. The inverter unit 170 extends in a direction perpendicular to the axial direction AD.

[0038] The motor device 60 and the inverter device 80 are aligned in the axial direction AD. For example, the inverter device 80 is provided between the motor device 60 and the propeller 20 in the axial direction AD. The motor shaft 64 is connected to the propeller 20 while passing through the inverter device 80 in the axial direction AD.

[0039] 2, the inverter device 80 includes an inverter circuit 81, a smoothing capacitor 145, a filter circuit 150, and a control circuit 160. In Fig. 3, the motor 61 is shown as MG, the filter circuit 150 as EMI, and the control circuit 160 as CD.

[0040] The propulsion system 30 has a P line 141, an N line 142, and an output line 143. The P line 141 and the N line 142 electrically connect the battery 31 and the inverter circuit 81. The P line 141 and the N line 142 are formed by bus bars, electrical wiring, etc. At least a portion of the P line 141 and at least a portion of the N line 142 are included in the inverter device 80.

[0041] The P line 141 is electrically connected to the positive electrode of the battery 31. The N line 142 is electrically connected to the negative electrode of the battery 31. In the battery 31, the positive electrode is the high-potential electrode, and the negative electrode is the low-potential electrode. The P line 141 and the N line 142 are power lines for supplying power from the battery 31 to the inverter circuit 81. The P line 141 is a high-potential power line and may be referred to as a high-potential line. The N line 142 is a low-potential power line and may be referred to as a low-potential line.

[0042] The output line 143 is a power line for supplying power from the inverter circuit 81 to the motor 61. The output line 143 electrically connects the motor 61 and the inverter circuit 81. For example, the output line 143 is electrically connected to the motor stator 62. The output line 143 is formed by a bus bar, electrical wiring, or the like. At least a portion of the output line 143 is included in the inverter device 80.

[0043] The smoothing capacitor 145 is a capacitor that smoothes the DC voltage supplied from the battery 31. The smoothing capacitor 145 is connected to the P line 141 and the N line 142 between the battery 31 and the inverter circuit 81. The smoothing capacitor 145 is connected in parallel to the inverter circuit 81.

[0044] The filter circuit 150 is a circuit for reducing noise such as electromagnetic noise. An example of the filter circuit 150 is an EMI filter. The filter circuit 150 is provided between the smoothing capacitor 145 and the battery 31. The filter circuit 150 is connected in parallel to the inverter circuit 81 and the battery 31. The filter circuit 150 has a choke coil and a filter capacitor. Examples of the choke coil include a common mode coil and a normal mode coil. Examples of the filter capacitor include a Y capacitor and an X capacitor.

[0045] The inverter circuit 81 is a circuit for converting power. The inverter circuit 81 performs power conversion for each of the multiple phases. The inverter circuit 81 converts DC power from the battery 31 into AC power and supplies the AC power to the motor 61. For example, the inverter circuit 81 is a DC-AC conversion circuit.

[0046] The inverter circuit 81 has upper and lower arm circuits 83 for a plurality of phases. For example, the inverter circuit 81 has an upper and lower arm circuit 83 for each of the U phase, V phase, and W phase. The upper and lower arm circuit 83 has an upper arm 84 and a lower arm 85. The upper arm 84 and the lower arm 85 are connected in series to the battery 31. The output line 143 is connected between the upper arm 84 and the lower arm 85 in the upper and lower arm circuit 83. The upper arm 84 is connected to the P line 141 and the output line 143. The lower arm 85 is connected to the N line 142 and the output line 143.

[0047] The upper arm 84 and the lower arm 85 have an arm switch 86 and an arm diode 87. The arm switch 86 is formed of a semiconductor switch or the like. A semiconductor switch is a switch that does not have mechanical contacts. The arm switch 86 is a transistor such as a MOSFET or an IGBT. MOSFET is an abbreviation for Metal-Oxide-Semiconductor Field-Effect Transistor. IGBT is an abbreviation for Insulated Gate Bipolar Transistor. The arm switch 86 is a switching element that can convert power by switching. The switching element is a semiconductor element such as a power element. The arm switch 86 is a conversion switch for converting power.

[0048] The arm diode 87 is a freewheeling diode. The arm diode 87 is connected in antiparallel to the arm switch 86. The arm diode 87 may be a parasitic diode of the arm switch 86, or may be a diode provided separately from the parasitic diode.

[0049] The control circuit 160 performs motor control to control the motor 61. The motor control includes control of the inverter circuit 81. The control circuit 160 is a control device such as an ECU. The control circuit 160 is sometimes referred to as an inverter control unit or a motor control unit. The control circuit 160 is communicatively connected to the inverter circuit 81. The control circuit 160 outputs a command signal to perform motor control via the inverter circuit 81.

[0050] The inverter device 80 includes a drive circuit. The drive circuit is a circuit for driving the inverter circuit 81. The control circuit 160 is communicatively connected to the inverter circuit 81 via the drive circuit. The drive circuit is electrically connected to the arm switch 86. The drive circuit generates a drive voltage in response to a command signal from the control circuit 160. The drive circuit applies the drive voltage to the arm switch 86, thereby driving the arm switch 86.

[0051] 3 , in the propulsion device 100, a propeller wind Wp is generated as the propeller 20 rotates. The propeller wind Wp flows in the axial direction AD as a whole. The propeller wind Wp is an airflow generated by the flow of gas such as air. The gas that generates the airflow such as the propeller wind Wp is sometimes referred to as a refrigerant. In this embodiment, the propeller wind Wp flows from the propeller 20 toward the EPU 50. In the EPU 50, the propeller wind Wp flows from the inverter device 80 toward the motor device 60. With respect to the propeller wind Wp, the inverter device 80 is located upstream of the motor device 60.

[0052] As shown in FIG. 3 , the motor housing 70 has a motor housing main body 71 and motor fins 72. The motor housing main body 71 and the motor fins 72 are made of a metal material or the like and have thermal conductivity. The motor housing main body 71 forms the inner and outer surfaces of the motor housing 70. The outer surface of the motor housing main body 71 includes a motor outer peripheral surface 710, a motor upstream surface 711, and a motor downstream surface 712. The motor outer peripheral surface 710 is formed in an annular shape and extends in the axial direction AD. The motor 61 is housed on the inner periphery of the motor outer peripheral surface 710.

[0053] The motor upstream surface 711 and the motor downstream surface 712 are aligned in the axial direction AD via the motor outer peripheral surface 710. The motor upstream surface 711 and the motor downstream surface 712 extend in a direction perpendicular to the axial direction AD. The motor upstream surface 711 and the motor downstream surface 712 cover the motor 61 from the axial direction AD. With respect to the propeller wind Wp, the motor upstream surface 711 is located upstream of the motor downstream surface 712.

[0054] The motor fins 72 are provided on the outer surface of the motor housing 70. The motor fins 72 are heat dissipation fins for dissipating heat from the motor device 60 to the outside. The motor fins 72 extend in a direction perpendicular to the circumferential direction CD. For example, the motor fins 72 are provided on the motor outer peripheral surface 710. The motor fins 72 extend from the motor outer peripheral surface 710 toward the outer periphery. The motor fins 72 extend in the axial direction AD along the motor outer peripheral surface 710. A plurality of motor fins 72 are arranged in the circumferential direction CD along the motor outer peripheral surface 710.

[0055] As shown in FIGS. 3 and 6 , the inverter housing 90 has an inverter housing main body 91 and inverter fins 92. The inverter housing main body 91 and the inverter fins 92 are formed from a metal material or the like and have thermal conductivity. The inverter housing main body 91 forms the inner and outer surfaces of the inverter housing 90. The outer surface of the inverter housing main body 91 includes an inverter outer peripheral surface 910, an inverter upstream surface 911, and an inverter downstream surface 912. The inverter outer peripheral surface 910 is formed in an annular shape and extends in the axial direction AD. The inverter section 170 is accommodated on the inner peripheral side of the inverter outer peripheral surface 910. The inverter housing 90 corresponds to a housing. The inverter outer peripheral surface 910 corresponds to a housing outer peripheral surface.

[0056] The inverter upstream surface 911 and the inverter downstream surface 912 are aligned in the axial direction AD via the inverter outer peripheral surface 910. The inverter upstream surface 911 and the inverter downstream surface 912 extend in a direction perpendicular to the axial direction AD. The inverter upstream surface 911 and the inverter downstream surface 912 cover the inverter unit 170 from the axial direction AD. The inverter upstream surface 911 corresponds to a housing cover surface. With respect to the propeller wind Wp, the inverter upstream surface 911 is located upstream of the inverter downstream surface 912.

[0057] In the EPU 50, the motor upstream surface 711 and the inverter downstream surface 912 are overlapped. In the EPU 50, the motor outer peripheral surface 710 and the inverter outer peripheral surface 910 are aligned in the axial direction AD. With respect to the propeller wind Wp, the inverter upstream surface 911 is provided upstream of the motor downstream surface 712.

[0058] The inverter housing main body 91 has an inverter outer peripheral wall 95, an inverter upstream wall 96, and an inverter downstream wall 97. The inverter outer peripheral wall 95 forms an inverter outer surface 910. The inverter outer peripheral surface 910 is the outer peripheral surface of the inverter outer peripheral wall 95. The inverter outer peripheral wall 95 is formed in a cylindrical shape and extends in the axial direction AD. The inverter section 170 is housed on the inner peripheral side of the inverter outer peripheral wall 95.

[0059] The inverter upstream wall 96 forms an inverter upstream surface 911. The inverter upstream surface 911 is the outer surface of the inverter upstream wall 96. The inverter downstream wall 97 forms an inverter downstream surface 912. The inverter downstream surface 912 is the outer surface of the inverter downstream wall 97. The inverter upstream wall 96 and the inverter downstream wall 97 are aligned in the axial direction AD via the inverter outer peripheral wall 95. The inverter upstream wall 96 and the inverter downstream wall 97 extend in a direction perpendicular to the axial direction AD. The inverter upstream wall 96 and the inverter downstream wall 97 cover the inverter section 170 from the axial direction AD. The inverter upstream wall 96 and the inverter downstream wall 97 close the inner space of the inverter outer peripheral wall 95 from the axial direction AD. With respect to the propeller wind Wp, the inverter upstream wall 96 is located upstream of the inverter downstream wall 97.

[0060] The inverter upstream surface 911 has an outer peripheral upstream surface 911a, an inner peripheral upstream surface 911b, and a stepped upstream surface 911c. The outer peripheral upstream surface 911a extends in the circumferential direction CD along the outer peripheral edge of the inverter upstream surface 911. The outer peripheral upstream surface 911a corresponds to an outer peripheral covering surface. The inner peripheral upstream surface 911b extends in the circumferential direction CD along the inner peripheral edge of the inverter upstream surface 911 and the outer peripheral surface of the motor shaft 64. The inner peripheral upstream surface 911b corresponds to an inner peripheral covering surface. The outer peripheral upstream surface 911a and the inner peripheral upstream surface 911b extend in a direction perpendicular to the axial direction AD. The inner peripheral upstream surface 911b is located at a position that protrudes in the axial direction AD more than the outer peripheral upstream surface 911a. With respect to the propeller wind Wp, the inner peripheral upstream surface 911b is located upstream of the outer peripheral upstream surface 911a.

[0061] The stepped upstream surface 911c connects the outer peripheral upstream surface 911a and the inner peripheral upstream surface 911b so as to form a stepped surface between them. The stepped upstream surface 911c is provided between the outer peripheral upstream surface 911a and the inner peripheral upstream surface 911b in the axial direction AD. The stepped upstream surface 911c extends in the circumferential direction CD along the outer peripheral upstream surface 911a and the inner peripheral upstream surface 911b. The stepped upstream surface 911c extends in a direction perpendicular to the radial direction RD.

[0062] The inverter upstream wall 96 has an outer peripheral upstream wall 96a, an inner peripheral upstream wall 96b, and a stepped upstream wall 96c. The outer peripheral upstream wall 96a forms an outer peripheral upstream surface 911a. The outer peripheral upstream surface 911a is the outer surface of the outer peripheral upstream wall 96a. The outer peripheral upstream wall 96a extends in the circumferential direction CD along the outer peripheral edge of the inverter upstream wall 96. The inner peripheral upstream wall 96b forms an inner peripheral upstream surface 911b. The inner peripheral upstream surface 911b is the outer surface of the inner peripheral upstream wall 96b. The inner peripheral upstream wall 96b extends in the circumferential direction CD along the inner peripheral edge of the inverter downstream wall 97 and the outer peripheral surface of the motor shaft 64. The outer peripheral upstream wall 96a and the inner peripheral upstream wall 96b extend in a direction perpendicular to the axial direction AD. The inner peripheral upstream wall 96b is located at a position protruding in the axial direction AD from the outer peripheral upstream wall 96a. With respect to the propeller wind Wp, the inner peripheral upstream wall 96b is provided upstream of the outer peripheral upstream wall 96a.

[0063] The stepped upstream wall 96c forms a stepped upstream surface 911c. The stepped upstream surface 911c is the outer surface of the stepped upstream wall 96c. The stepped upstream wall 96c connects the outer peripheral upstream wall 96a and the inner peripheral upstream wall 96b so as to form a step between them. The stepped upstream wall 96c is provided between the outer peripheral upstream wall 96a and the inner peripheral upstream wall 96b in at least one of the axial direction AD and the radial direction RD. The stepped upstream wall 96c extends in the circumferential direction CD along the outer peripheral upstream wall 96a and the inner peripheral upstream wall 96b. The stepped upstream wall 96c extends in a direction perpendicular to the radial direction RD.

[0064] 5 and 6 , the inverter unit 170 includes the inverter circuit 81, smoothing capacitor 145, filter circuit 150, control circuit 160, and the like. The inverter unit 170 includes an inverter board 171, switch components 175, capacitor components 176, and filter components 177. The inverter board 171 is a circuit board. The inverter board 171 extends in a direction perpendicular to the axial direction AD along the inverter upstream wall 96 and the inverter downstream wall 97. The inverter board 171 is disposed between the inverter upstream wall 96 and the inverter downstream wall 97. In the axial direction AD, the distance between the inverter board 171 and the outer peripheral upstream wall 96 a is smaller than the distance between the inverter board 171 and the inner peripheral upstream wall 96 b.

[0065] The switch component 175, the capacitor component 176, and the filter component 177 are electric or electronic components. The components 175 to 177 are mounted on the inverter board 171. The components 175 to 177 protrude from the inverter board 171 toward the inverter upstream wall 96. At least a portion of each of the components 175 to 177 is provided between the inverter board 171 and the inverter upstream wall 96.

[0066] The switch component 175 is a component that forms the arm switch 86. The capacitor component 176 is a component that forms the smoothing capacitor 145. The filter component 177 is a component that forms the filter circuit 150. Examples of the filter component 177 include a component that forms a choke coil and a component that forms a filter capacitor. Note that the capacitor component 176 may also be a component that forms a filter capacitor.

[0067] A plurality of switch components 175 are arranged in the circumferential direction CD along the inverter outer peripheral surface 910. The switch components 175 correspond to outer peripheral components. The capacitor components 176 and the filter components 177 are provided on the inner peripheral side of the switch components 175. For example, the capacitor components 176 and the filter components 177 are provided at positions spaced apart from the inner peripheral side of the switch components 175. The capacitor components 176 and the filter components 177 correspond to inner peripheral components. The capacitor components 176 and the filter components 177 are provided at positions spaced apart from the outer peripheral side of the motor shaft 64.

[0068] At least a portion of the switch component 175 is provided on the outer peripheral upstream surface 911a in a position aligned in the axial direction AD. For example, the switch component 175 is provided between the inner peripheral end and the outer peripheral end of the outer peripheral upstream surface 911a in the radial direction RD. The switch component 175 protrudes from the inverter board 171 toward the outer peripheral upstream wall 96a in the axial direction AD. At least a portion of the switch component 175 is provided between the inverter board 171 and the outer peripheral upstream wall 96a.

[0069] At least a portion of the capacitor component 176 is disposed on the inner circumferential upstream surface 911b in a position aligned with the axial direction AD. For example, the capacitor component 176 is disposed between the inner circumferential end and the outer circumferential end of the inner circumferential upstream surface 911b in the radial direction RD. The capacitor component 176 protrudes from the inverter board 171 toward the inner circumferential upstream wall 96b in the axial direction AD. At least a portion of the capacitor component 176 is disposed between the inverter board 171 and the inner circumferential upstream wall 96b.

[0070] At least a portion of the filter component 177 is disposed on the inner circumferential upstream surface 911b in a position aligned with the axial direction AD. For example, the filter component 177 is disposed between the inner circumferential end and the outer circumferential end of the inner circumferential upstream surface 911b in the radial direction RD. The filter component 177 protrudes from the inverter board 171 toward the inner circumferential upstream wall 96b in the axial direction AD. At least a portion of the filter component 177 is disposed between the inverter board 171 and the inner circumferential upstream wall 96b.

[0071] The capacitor component 176 and the filter component 177 are components that are taller in the axial direction AD than the switch component 175. For example, with respect to the protruding dimension from the inverter board 171 to the inverter upstream wall 96, the protruding dimension of the capacitor component 176 is larger than the protruding dimension of the switch component 175. Similarly, the protruding dimension of the filter component 177 is larger than the protruding dimension of the switch component 175. The capacitor component 176 and the filter component 177 correspond to tall components. The switch component 175 corresponds to a short component.

[0072] The switch component 175, the capacitor component 176, and the filter component 177 are all provided in contact with or close to the inverter upstream wall 96. The distance between the inner circumferential upstream wall 96b and the inverter board 171 is set to be large in accordance with the relatively tall height of the capacitor component 176 and the filter component 177. The distance between the outer circumferential upstream wall 96a and the inverter board 171 is set to be small in accordance with the relatively short height of the switch component 175.

[0073] In the EPU 50, the motor device 60 and the inverter device 80 generate heat as the motor 61 is driven. In the motor device 60, the motor 61 and other components generate heat as current is passed through the motor 61. In the inverter device 80, the inverter unit 170 and other components generate heat as current is passed through the inverter unit 170. For example, in the inverter device 80, the switch components 175, capacitor components 176, filter components 177, and other components generate heat as current is passed through the arm switch 86, smoothing capacitor 145, and filter circuit 150. The inverter unit 170 corresponds to a heat-generating component. The switch components 175, capacitor components 176, and filter components 177 correspond to heat-generating components.

[0074] The control circuit 160 and the drive circuit may be formed by the inverter board 171, or may be formed by another circuit board different from the inverter board 171. For example, the other circuit board is accommodated in the inverter housing 90 together with the inverter board 171, for example, by being arranged next to the inverter board 171 in the axial direction AD.

[0075] As shown in FIGS. 3 and 6 , the inverter fins 92 are provided on the outer surface of the inverter housing 90. The inverter fins 92 are heat dissipation fins for dissipating heat from the inverter device 80 to the outside. The inverter fins 92 extend from the outer surface of the inverter housing 90 in a direction perpendicular to the circumferential direction CD. The inverter fins 92 are provided to span between the inverter outer peripheral surface 910 and the inverter upstream surface 911. The inverter fins 92 extend radially outward from the inverter outer peripheral surface 910 and from the inverter upstream surface 911 in the axial direction AD. The inverter fins 92 extend in the axial direction AD along the inverter outer peripheral surface 910 and in the radial direction RD along the inverter upstream surface 911. The inverter fins 92 do not extend upstream of the inner circumferential upstream surface 911b. For example, the upstream end surface of the inverter fin 92 forms the same plane as the inner circumferential upstream surface 911b. The inverter fins 92 are arranged in a circumferential direction CD along both the inverter outer peripheral surface 910 and the inverter upstream surface 911. The inverter fins 92 correspond to outer peripheral fins and axial fins.

[0076] At least some of the inverter fins 92 are arranged in the radial direction RD on the inverter unit 170. For example, at least some of the inverter fins 92 are arranged in the radial direction RD on the switch component 175. Furthermore, at least some of the inverter fins 92 are arranged in the axial direction AD on the inverter unit 170. For example, at least some of the inverter fins 92 are arranged in the axial direction AD on the switch component 175.

[0077] 4 to 7 , the inverter fins 92 have parallel fin portions 111 and cross fin portions 121. The parallel fin portions 111 and the cross fin portions 121 extend in the axial direction AD so as to straddle the upstream end of the inverter outer peripheral surface 910. The parallel fin portions 111 and the cross fin portions 121 extend in the axial direction AD along the inverter outer peripheral surface 910 and protrude upstream from the inverter outer peripheral surface 910.

[0078] The parallel fin portion 111 extends in the radial direction RD along the motor radial line Crd. The parallel fin portion 111 extends parallel to the motor radial line Crd. The motor radial line Crd is a center line that passes through the motor axis Cm and extends in the radial direction RD. The motor radial line Crd is a linear imaginary line. The parallel fin portion 111 is formed in a plate shape and extends in a direction perpendicular to the circumferential direction CD. The parallel fin portion 111 has a pair of fin parallel surfaces 111a. The fin parallel surfaces 111a are plate surfaces of the parallel fin portion 111. The fin parallel surfaces 111a extend in a direction perpendicular to the circumferential direction CD. The pair of fin parallel surfaces 111a are aligned in the circumferential direction CD. The pair of fin parallel surfaces 111a extend parallel to each other. The pair of fin parallel surfaces 111a also extend parallel to the motor radial line Crd.

[0079] The cross fin section 121 extends from the parallel fin section 111 in the circumferential direction CD. For example, the cross fin section 121 extends from the parallel fin section 111 toward one side in the circumferential direction CD. The cross fin section 121 intersects the parallel fin section 111 and the motor radial line Crd. For example, the cross fin section 121 is perpendicular to the parallel fin section 111 and the motor radial line Crd. The cross fin section 121 is formed in a plate shape and extends in a direction perpendicular to the radial direction RD. The cross fin section 121 has a fin intersecting outer surface 121a and a fin intersecting inner surface 121b. The fin intersecting outer surface 121a is the outer peripheral surface of a pair of plate surfaces that the cross fin section 121 has. The fin intersecting inner surface 121b is the inner peripheral surface of a pair of plate surfaces that the cross fin section 121 has. The fin intersection outer surface 121a and the fin intersection inner surface 121b extend in a direction intersecting the fin parallel surface 111a. For example, the fin intersection outer surface 121a and the fin intersection inner surface 121b are perpendicular to the fin parallel surface 111a.

[0080] The cross fin section 121 is provided at a position spaced apart from the inverter outer peripheral surface 910 toward the outer periphery. The cross fin section 121 is provided at the outer peripheral end of the parallel fin section 111. For example, in the radial direction RD, the distance between the cross fin section 121 and the inverter outer peripheral surface 910 is greater than the thickness dimension of the cross fin section 121. Note that the distance between the cross fin section 121 and the inverter outer peripheral surface 910 may be smaller than the thickness dimension of the cross fin section 121 or may be the same as the thickness dimension of the cross fin section 121.

[0081] In two inverter fins 92 adjacent to each other in the circumferential direction CD, the respective cross fin portions 121 are provided at positions spaced apart in the circumferential direction CD. That is, a gap extending in the axial direction AD is formed between the two cross fin portions 121 adjacent to each other in the circumferential direction CD. In two inverter fins 92 adjacent to each other in the circumferential direction CD, the space between the respective parallel fin portions 111 opens outward from the gap between the respective cross fin portions 121 toward the outer periphery.

[0082] The parallel fin portion 111 has an outer circumferential parallel portion 112, an axial parallel portion 113, and an extended parallel portion 114. The outer circumferential parallel portion 112 is a portion of the parallel fin portion 111 that extends from the inverter outer circumferential surface 910 toward the outer circumferential side. The outer circumferential parallel portion 112 extends in the axial direction AD along the inverter outer circumferential surface 910. The outer circumferential parallel portion 112 corresponds to the outer circumferential fin portion and the radially extending portion. The outer circumferential parallel portion 112 spans between the upstream end and downstream end of the inverter outer circumferential surface 910. At least a portion of the outer circumferential parallel portion 112 is positioned adjacent to the switch component 175 in the radial direction RD. For example, the outer circumferential parallel portion 112 is positioned on the outer circumferential side of the switch component 175, straddling the switch component 175 in the axial direction AD. The switch component 175 is positioned between the upstream end and downstream end of the outer circumferential parallel portion 112 in the axial direction AD.

[0083] The axis-parallel portion 113 is a portion of the parallel fin portion 111 that extends from the inverter upstream surface 911 in the axial direction AD. The axis-parallel portion 113 extends in the radial direction RD along the inverter upstream surface 911. The axis-parallel portion 113 corresponds to a shaft fin portion. The axis-parallel portion 113 is provided on the outer peripheral upstream surface 911a so as to extend from the outer peripheral upstream surface 911a in the axial direction AD. The axis-parallel portion 113 extends in the radial direction RD along the outer peripheral upstream surface 911a. The axis-parallel portion 113 spans between the outer peripheral end and the inner peripheral end of the outer peripheral upstream surface 911a. The axis-parallel portion 113 is connected to the stepped upstream surface 911c. The axis-parallel portion 113 extends in the axial direction AD along the stepped upstream surface 911c. The axis-parallel portion 113 does not extend upstream of the inner peripheral upstream surface 911b. For example, the upstream end face of the axially parallel portion 113 forms the same plane as the inner circumferential upstream face 911b.

[0084] At least a portion of the axis-parallel portion 113 is provided at a position aligned with the switch component 175 in the axial direction AD. For example, the axis-parallel portion 113 is provided at a position aligned with the switch component 175 in the axial direction AD and straddling the switch component 175 in the radial direction RD. The switch component 175 is provided between the outer circumferential end and the inner circumferential end of the axis-parallel portion 113 in the radial direction RD.

[0085] The extended parallel portion 114 is a portion of the parallel fin portion 111 that connects the outer periphery parallel portion 112 and the axis parallel portion 113. The extended parallel portion 114 extends in the axial direction AD from the outer periphery parallel portion 112 toward the upstream side of the inverter outer periphery surface 910. The extended parallel portion 114 also extends from the axis parallel portion 113 toward the outer periphery side of the inverter outer periphery surface 910. The extended parallel portion 114 corresponds to an outer periphery extension portion, an axis extension portion, an extension base portion, and a radial extension portion. The extended parallel portion 114 spans between the inner periphery end and the outer periphery end of the outer periphery parallel portion 112 in the radial direction RD. The extended parallel portion 114 also spans between the upstream end and the downstream end of the axis parallel portion 113 in the axial direction AD.

[0086] The cross fin portion 121 has an outer circumferential intersection portion 122 and an extended intersection portion 124. The outer circumferential intersection portion 122 is a portion of the cross fin portion 121 that is aligned in the radial direction RD on the inverter outer circumferential surface 910. The outer circumferential intersection portion 122 extends from the outer circumferential parallel portion 112 in the circumferential direction CD. Like the outer circumferential parallel portion 112, the outer circumferential intersection portion 122 extends in the axial direction AD along the inverter outer circumferential surface 910. The outer circumferential intersection portion 122 corresponds to an outer circumferential fin portion, an outer circumferential limiting portion, and a circumferential extension portion. The outer circumferential intersection portion 122 spans between the upstream end and the downstream end of the outer circumferential parallel portion 112. At least a portion of the outer circumferential intersection portion 122 is aligned with the switch component 175 in the radial direction RD. For example, the outer circumferential intersection portion 122 is aligned with the switch component 175 in the axial direction AD. The switch component 175 is provided between the upstream end and downstream end of the outer circumferential intersection portion 122 in the axial direction AD.

[0087] The extended intersection portion 124 is a portion of the cross fin portion 121 that extends upstream from the outer circumferential intersection portion 122. The extended intersection portion 124 extends in the axial direction AD from the outer circumferential intersection portion 122 beyond the inverter outer circumferential surface 910. The extended intersection portion 124 corresponds to an outer circumferential extension portion, an outer circumferential limiting portion, an axial extension portion, an axial limiting portion, and a circumferential extension portion. The extended intersection portion 124 spans between the upstream end and the downstream end of the extended parallel portion 114 in the axial direction AD.

[0088] The cross fin portion 121 has a peripheral intersection portion 122 and an extended intersection portion 124, and is therefore included in both the peripheral fin portion and the peripheral extension portion. The cross fin portion 121 extends in the axial direction AD, straddling the boundary between the peripheral fin portion and the peripheral extension portion. In other words, the peripheral intersection portion 122 and the extended intersection portion 124 as a whole extend in the axial direction AD, straddling the boundary between the peripheral fin portion and the peripheral extension portion. The boundary between the peripheral intersection portion 122 and the extended intersection portion 124 corresponds to the boundary between the peripheral fin portion and the peripheral extension portion.

[0089] In the inverter housing 90, fin flow paths 130 are formed by the inverter fins 92. The fin flow paths 130 are spaces between two adjacent inverter fins 92 in the circumferential direction CD. The fin flow paths 130 are formed between two fin parallel surfaces 111a that face each other in the circumferential direction CD. The fin flow paths 130 extend along the outer surface of the inverter housing 90 in a direction perpendicular to the circumferential direction CD. The fin flow paths 130 include a flow path that extends in the radial direction RD along the inverter upstream surface 911 and a flow path that extends in the radial direction RD along the inverter outer peripheral surface 910.

[0090] The fin flow passage 130 is open toward the upstream side, downstream side, and outer periphery side. The fin flow passage 130 has a fin upstream port 131, a fin downstream port 132, and a fin outer periphery port 133. The fin upstream port 131 opens the fin flow passage 130 toward the upstream side in the axial direction AD. The fin upstream port 131 is formed by the upstream ends of the fin parallel surfaces 111a, etc. The fin upstream port 131 is an open port surrounded by two fin parallel surfaces 111a facing each other in the circumferential direction CD, the step upstream surface 911c, and the fin intersection inner surface 121b. At least a portion of the fin upstream port 131 is located in a position aligned with the outer periphery upstream surface 911a in the axial direction AD.

[0091] The fin downstream port 132 opens in the axial direction AD toward the downstream side of the fin flow path 130. The fin downstream port 132 is formed by the downstream ends of the fin parallel surfaces 111a, etc. The fin downstream port 132 is an open port surrounded by two fin parallel surfaces 111a facing each other in the circumferential direction CD, the inverter outer peripheral surface 910, and the fin intersection inner surface 121b. The fin downstream port 132 extends in the axial direction AD toward the opposite side from the extended parallel portion 114 and the extended intersection portion 124. The fin downstream port 132 corresponds to an opposite open port.

[0092] The fin outer peripheral opening 133 opens the fin flow path 130 toward the outer periphery. The fin outer peripheral opening 133 is formed by a gap between two adjacent cross fin sections 121 in the circumferential direction CD. For example, in the gap between two adjacent cross fin sections 121 in the circumferential direction CD, the outer peripheral edge or the inner peripheral edge serves as the fin outer peripheral opening 133. Note that the fin outer peripheral opening 133 may be located at a middle position in the axial direction AD within this gap. The fin outer peripheral opening 133 corresponds to an outer peripheral open opening.

[0093] 4 , the upstream opening area S131 is larger than both the downstream opening area S132 and the outer peripheral opening area S133. The outer peripheral opening area S133 is smaller than the downstream opening area S132. The upstream opening area S131 is the open area of ​​the fin upstream opening 131. The downstream opening area S132 is the open area of ​​the fin downstream opening 132. The outer peripheral opening area S133 is the open area of ​​the fin outer peripheral opening 133. In addition, in the radial direction RD, the width dimension D2 of the fin outer peripheral opening 133 is smaller than the width dimension D1 of the cross fin section 121.

[0094] 3 , the propeller wind Wp traveling in the axial direction AD toward the inverter upstream surface 911 avoids the inverter upstream surface 911 as it approaches the inverter upstream surface 911 and flows in a manner that expands toward the outer periphery. This propeller wind Wp continues to flow toward the outer periphery after avoiding the inverter upstream surface 911, and therefore tends to move away from the inverter fins 92 and the inverter outer periphery surface 910 toward the outer periphery. For this reason, there is a concern that the propeller wind Wp flowing along the inverter fins 92 and the inverter outer periphery surface 910 will be insufficient. In other words, there is a concern that the cooling effect of the propeller wind Wp on the inverter housing 90 will be insufficient.

[0095] In contrast to this, in the present embodiment, the propeller wind Wp flowing toward the outer periphery along the inverter upstream surface 911 is restricted from passing through the inverter fins 92 in the radial direction RD by the cross fin portion 121. The propeller wind Wp is guided by the cross fin portion 121 so as to flow in the axial direction AD along the inverter outer periphery surface 910.

[0096] 4 , 6 , and 7 , the propeller wind Wp includes a first propeller wind Wp1 and a second propeller wind Wp2. The propeller winds Wp1 and Wp2 approach or hit the inverter upstream surface 911, and flow toward the outer periphery along the inverter upstream surface 911. The propeller winds Wp1 and Wp2 flow from the fin upstream port 131 into the fin flow path 130, and flow toward the outer periphery in the fin flow path 130 along the outer periphery upstream surface 911 a, the axis-parallel portion 113, and the extended parallel portion 114. As the propeller winds Wp1 and Wp2 flow along the axis-parallel portion 113 and the extended parallel portion 114, heat from the inverter housing 90 is easily released from the axis-parallel portion 113 and the extended parallel portion 114 to the propeller winds Wp1 and Wp2.

[0097] After passing through the inverter upstream surface 911 toward the outer periphery, the first propeller wind Wp1 is restricted by the cross fin portion 121 from further advancing toward the outer periphery. When the first propeller wind Wp1 approaches or hits the outer periphery intersection portion 122 or the extended intersection portion 124, it changes its direction of travel so that it flows in the axial direction AD along the inverter outer periphery surface 910. In other words, the first propeller wind Wp1 is guided by the cross fin portion 121 so that it flows toward the downstream side through the fin flow path 130. The first propeller wind Wp1 flows toward the downstream side through the fin flow path 130 and flows out from the fin downstream port 132. The first propeller wind Wp1 is restricted by the cross fin portion 121 from flowing out toward the outer periphery from the fin outer periphery port 133. As the first propeller wind Wp1 is guided in the axial direction AD by the cross fin portion 121, heat is easily released from the outer periphery parallel portion 112, the cross fin portion 121, and the inverter outer periphery surface 910 to the first propeller wind Wp1.

[0098] The second propeller wind Wp2 passes through the inverter upstream surface 911 toward the outer periphery, then passes between two cross fin sections 121 adjacent in the circumferential direction CD, and flows out from the fin outer peripheral opening 133. In the fin flow path 130, the second propeller wind Wp2 is likely to be smaller than the first propeller wind Wp1 due to the small width dimension D2 and outer peripheral opening area S133 of the fin outer peripheral opening 133. Therefore, an increase in the second propeller wind Wp2 is unlikely to reduce the cooling effect of the first propeller wind Wp1 on the inverter housing 90. On the other hand, the flow of the second propeller wind Wp2 out of the fin outer peripheral opening 133 reduces pressure loss in the fin flow path 130. Therefore, an insufficient amount or speed of the first propeller wind Wp1 passing through the fin flow path 130 in the axial direction AD is unlikely to occur.

[0099] The inverter fins 92 of this embodiment will now be described in detail. The EPU 50, which is an electric propulsion unit, is a product made up of a motor 61 that drives the propeller 20 and an inverter unit 170 that drives the motor 61. The motor 61 and the inverter unit 170 generate heat due to losses during operation and therefore require cooling. In the eVTOL 10, the EPU 50 is generally cooled by air to reduce its weight. Specifically, the airflow generated by the propeller 20 and the airflow generated by a fan separate from the propeller 20 pass through heat dissipation fins installed on the outer surface of the housing of the EPU 50, thereby dissipating heat from the EPU 50.

[0100] Weight reduction is extremely important for the eVTOL 10. Reducing the height of the inverter housing 90 is effective in reducing the weight of the inverter device 80. However, there is a concern that this will make it difficult for air to flow around the inverter housing 90, which could worsen the heat dissipation performance of the inverter housing 90. In contrast, this embodiment can achieve both a low profile for the inverter housing 90 and the formation of airflow along the outer surface of the inverter housing 90.

[0101] As the height of the inverter housing 90 is reduced, components included in the inverter unit 170 that particularly require heat dissipation need to be placed close to or in contact with the inverter upstream wall 96. Components in the inverter unit 170 that particularly require heat dissipation include switch components 175 such as semiconductor switches, capacitor components 176, and filter components 177 such as choke coils. In contrast, the inverter fins 92 have axis-parallel portions 113 provided on the inverter upstream wall 96. Therefore, the axis-parallel portions 113 promote heat dissipation from the switch components 175, capacitor components 176, and filter components 177.

[0102] According to the present embodiment described so far, in the inverter fins 92, the extended parallel portions 114 extend from the outer peripheral parallel portions 112 in the axial direction AD further than the inverter outer peripheral surface 910. Furthermore, the extended intersection portions 124 extend from the outer peripheral intersection portions 122 in the axial direction AD further than the inverter outer peripheral surface 910. With this configuration, the propeller winds Wp1, Wp2 flowing in the axial direction AD toward the inverter housing 90 tend to flow along at least one of the extended parallel portions 114 and the extended intersection portions 124 when they avoid the inverter housing 90 and expand outward. Therefore, the heat dissipation effect of the inverter fins 92 can be enhanced by at least one of the extended parallel portions 114 and the extended intersection portions 124.

[0103] Furthermore, between two inverter fins 92 adjacent to each other in the circumferential direction CD, the first propeller wind Wp1 is restricted from passing through the inverter fins 92 in the radial direction RD by at least one of the outer circumferential intersection portion 122 and the extended intersection portion 124. Between two inverter fins 92 adjacent to each other in the circumferential direction CD, the first propeller wind Wp1 flowing toward the outer periphery is guided by at least one of the outer circumferential intersection portion 122 and the extended intersection portion 124 so as to flow in the axial direction AD along the inverter outer circumferential surface 910. This makes it easy for the first propeller wind Wp1 flowing along at least one of the outer circumferential parallel portion 112 and the outer circumferential intersection portion 122 to increase. Therefore, the heat dissipation effect of the outer circumferential parallel portion 112 and the outer circumferential intersection portion 122 can be enhanced by at least one of the outer circumferential intersection portion 122 and the extended intersection portion 124.

[0104] As described above, the heat dissipation effect of the inverter housing 90 in the EPU 50 can be improved by the inverter fins 92 .

[0105] According to this embodiment, the outer circumferential intersection portion 122 and the extended intersection portion 124 are provided so that a fin outer circumferential opening 133 is formed between two inverter fins 92 adjacent to each other in the circumferential direction CD. In this configuration, the second propeller wind Wp2 that flows into the fin flow path 130 from the fin upstream opening 131 is likely to flow out from the fin outer circumferential opening 133. In the fin flow path 130, pressure loss is likely to be reduced by the amount of the second propeller wind Wp2 that flows out from the fin outer circumferential opening 133, and therefore the amount and speed of the first propeller wind Wp1 passing through the fin flow path 130 in the axial direction AD are likely to increase. This makes it possible to enhance the cooling effect of the inverter fins 92 by the first propeller wind Wp1.

[0106] According to this embodiment, in the fin flow path 130, the outer peripheral opening area S133 of the fin outer peripheral opening 133 is smaller than the downstream opening area S132 of the fin downstream opening 132. In this configuration, the amount of second propeller wind Wp2 flowing out from the fin outer peripheral opening 133 is likely to be smaller than the amount of first propeller wind Wp1 flowing out from the fin downstream opening 132. This makes it possible to realize a configuration in which the second propeller wind Wp2 is likely to be reduced and the first propeller wind Wp1 is likely to be increased. This makes it possible to prevent a decrease in the cooling effect of the inverter fins 92 due to a shortage of first propeller wind Wp1.

[0107] According to this embodiment, the outer periphery parallel portion 112 and the outer periphery intersection portion 122 are provided at positions on the outer periphery side of the switch component 175 so as to straddle the switch component 175 in the axial direction AD. In this configuration, even if the switch component 175 generates heat as the EPU 50 is driven, the heat from the switch component 175 is easily transferred to at least one of the outer periphery parallel portion 112 and the outer periphery intersection portion 122. Therefore, the heat dissipation effect of the switch component 175 can be improved by at least one of the outer periphery parallel portion 112 and the outer periphery intersection portion 122.

[0108] According to this embodiment, the cross fin portion 121 has both an outer circumferential intersection portion 122 included in the outer circumferential fin portion and an extended intersection portion 124 included in the outer circumferential extension portion. Therefore, upstream of the inverter outer circumferential surface 910, the extended intersection portion 124 can guide the first propeller wind Wp1 in the axial direction AD. Furthermore, at a position aligned with the inverter outer circumferential surface 910 in the radial direction RD, the outer circumferential intersection portion 122 can guide the first propeller wind Wp1 in the axial direction AD. Therefore, the outer circumferential intersection portion 122 can prevent the first propeller wind Wp1 guided in the axial direction AD by the extended intersection portion 124 from flowing out of the fin flow path 130 to the outer circumferential side.

[0109] According to the present embodiment, the outer circumferential intersection 122 is provided at a position on the outer circumferential side of the switch component 175 so as to straddle the switch component 175 in the axial direction AD. In this configuration, the outer circumferential intersection 122 restricts the first propeller wind Wp1 from flowing toward the outer circumferential side, so that heat from portions of the inverter outer circumferential surface 910 and the outer circumferential parallel portion 112 that are close to the switch component 175 is easily released to the first propeller wind Wp1. Therefore, the outer circumferential intersection 122 can enhance the heat dissipation effect of the switch component 175.

[0110] According to this embodiment, the axis-parallel portion 113 extends from the inverter upstream surface 911 in the axial direction AD. In this configuration, when the propeller winds Wp1 and Wp2 flow along the inverter upstream surface 911 toward the outer periphery, they tend to flow along the axis-parallel portion 113. This allows the axis-parallel portion 113 to enhance the heat dissipation effect of the inverter fins 92. Furthermore, the extended parallel portion 114 extends from the axis-parallel portion 113 toward the outer periphery of the inverter outer periphery surface 910. In this configuration, the extended parallel portion 114 is supported by both the outer periphery parallel portion 112 and the axis-parallel portion 113. This allows for increased support strength for the extended parallel portion 114 in the inverter fins 92 compared to, for example, a configuration in which the extended parallel portion 114 is cantilevered by only one of the outer periphery parallel portion 112 and the axis-parallel portion 113.

[0111] According to this embodiment, the axis-parallel portion 113 is provided at a position aligned with the switch component 175 in the axial direction AD and straddling the switch component 175 in the radial direction RD. In this configuration, heat from the switch component 175 is easily transferred to the axis-parallel portion 113. Therefore, the axis-parallel portion 113 can enhance the heat dissipation effect of the switch component 175.

[0112] According to the present embodiment, the outer circumferential intersection portion 122 is provided at a position spaced radially outward from the inverter outer circumferential surface 910, and extends from the outer circumferential parallel portion 112 in the circumferential direction CD. In this configuration, the outer circumferential intersection portion 122 is bent in the circumferential direction CD with respect to the outer circumferential parallel portion 112. In addition, the extended intersection portion 124 is provided at a position spaced radially outward from the inverter outer circumferential surface 910, and extends from the extended parallel portion 114 in the circumferential direction CD. In this configuration, the extended intersection portion 124 is bent in the circumferential direction CD with respect to the extended parallel portion 114. With these configurations, at least one of the outer circumferential intersection portion 122 and the extended intersection portion 124 can restrict the first propeller wind Wp1 from flowing radially outward and passing through the inverter fins 92.

[0113] According to this embodiment, the inverter unit 170 is housed as a heat-generating part in the inverter housing 90. In this configuration, the inverter fins 92 can prevent the temperature of the inverter device 80 from rising excessively due to heat generated by the inverter unit 170.

[0114] According to this embodiment, the EPU 50 is driven to fly the eVTOL 10. In this configuration, when the eVTOL 10 is flying due to the driving of the EPU 50, the inverter fins 92 can prevent the temperature of the EPU 50 from rising excessively due to insufficient heat dissipation effect of the inverter housing 90. Therefore, the inverter fins 92 can improve the safety of the eVTOL 10.

[0115] According to the present embodiment, in the inverter fins 92, the extending parallel portions 114 extend from the axis-parallel portions 113 toward the outer periphery of the inverter outer periphery 910. With this configuration, when the propeller winds Wp1 and Wp2 flowing in the axial direction AD toward the inverter housing 90 avoid the inverter housing 90 and expand toward the outer periphery, they tend to flow along at least one of the axis-parallel portions 113 and the extending parallel portions 114. Therefore, the heat dissipation effect of the inverter fins 92 can be improved by at least one of the axis-parallel portions 113 and the extending parallel portions 114.

[0116] Furthermore, between two inverter fins 92 adjacent to each other in the circumferential direction CD, the extended intersection portion 124 restricts the first propeller wind Wp1 from flowing through the inverter fins 92 in the radial direction RD. Between two inverter fins 92 adjacent to each other in the circumferential direction CD, the extended intersection portion 124 guides the first propeller wind Wp1 flowing toward the outer periphery so that it flows in the axial direction AD along the inverter outer periphery surface 910. This makes it easy for the first propeller wind Wp1 flowing along the inverter outer periphery surface 910 to increase. Therefore, the extended intersection portion 124 can enhance the heat dissipation effect of the inverter outer periphery surface 910.

[0117] Second Embodiment In the first embodiment, the inverter fins 92 do not extend upstream of the inner circumferential upstream surface 911b. In contrast, in the second embodiment, the inverter fins 92 extend upstream of the inner circumferential upstream surface 911b. Configurations, actions, and effects that are not specifically described in the second embodiment are the same as those in the first embodiment. The second embodiment will be described mainly focusing on differences from the first embodiment.

[0118] 8, at least a portion of the inverter fin 92 extends in the axial direction AD upstream beyond the inner circumferential upstream surface 911b. For example, in the inverter fin 92, both the parallel fin portion 111 and the cross fin portion 121 extend upstream beyond the inner circumferential upstream surface 911b. In the parallel fin portion 111, the axially parallel portion 113 extends upstream beyond the inner circumferential upstream surface 911b. In the cross fin portion 121, the extended cross portion 124 extends upstream beyond the inner circumferential upstream surface 911b.

[0119] In the inverter housing 90, the parallel fin portion 111 extends upstream of the inner circumferential upstream surface 911b, so that at least a portion of the fin flow path 130 is formed upstream of the inner circumferential upstream surface 911b. With this configuration, even if the propeller winds Wp1, Wp2 flow toward the outer periphery at a position away from the inner circumferential upstream surface 911b, the propeller winds Wp1, Wp2 tend to flow into the fin flow path 130. Therefore, the propeller winds Wp1, Wp2 flowing through the fin flow path 130 tend to increase, thereby improving the cooling effect of the inverter fins 92 on the propeller winds Wp1, Wp2.

[0120] Third Embodiment In the first embodiment, a step surface is formed on the inverter upstream surface 911 by the step upstream surface 911c. In contrast, in the third embodiment, the step surface of the inverter upstream surface 911 is gentler. Configurations, actions, and effects that are not specifically described in the third embodiment are the same as those of the first embodiment. The third embodiment will be described mainly focusing on differences from the first embodiment.

[0121] As shown in Figures 9, 10, and 11, the inverter upstream surface 911 has an inclined upstream surface 911d instead of the stepped upstream surface 911c of the first embodiment. The inclined upstream surface 911d connects the outer peripheral upstream surface 911a and the inner peripheral upstream surface 911b so as to smooth the step between them. The inclined upstream surface 911d is provided between the outer peripheral upstream surface 911a and the inner peripheral upstream surface 911b in the axial direction AD and the radial direction RD. The inclined upstream surface 911d extends in the circumferential direction CD along the outer peripheral upstream surface 911a and the inner peripheral upstream surface 911b. The inclined upstream surface 911d is inclined with respect to the outer peripheral upstream surface 911a and the inner peripheral upstream surface 911b. The inclined upstream surface 911d is inclined with respect to the motor radial line Crd so as to face the outer periphery. The inclined upstream surface 911d corresponds to an inclined covering surface.

[0122] The inclined upstream surface 911d extends tapered toward the outer periphery. The inclined upstream surface 911d is a tapered surface. The inclined upstream surface 911d may be curved so as to bulge upstream or so as to be concave downstream. The inclined upstream surface 911d may also be a curved surface or a bent surface.

[0123] The inverter upstream wall 96 has an inclined upstream wall 96d instead of the stepped upstream wall 96c of the first embodiment. The inclined upstream wall 96d forms an inclined upstream surface 911d. The inclined upstream surface 911d is the outer surface of the inclined upstream wall 96d. The inclined upstream wall 96d connects the outer peripheral upstream wall 96a and the inner peripheral upstream wall 96b so as to reduce the step between the outer peripheral upstream wall 96a and the inner peripheral upstream wall 96b. The inclined upstream wall 96d is provided between the outer peripheral upstream wall 96a and the inner peripheral upstream wall 96b in the axial direction AD and the radial direction RD. The inclined upstream wall 96d extends in the circumferential direction CD along the outer peripheral upstream wall 96a and the inner peripheral upstream wall 96b. The inclined upstream wall 96d is inclined with respect to the outer peripheral upstream wall 96a and the inner peripheral upstream wall 96b.

[0124] The inverter upstream surface 911 has a flared upstream surface 911e. The flared upstream surface 911e connects the inverter outer peripheral surface 910 and the outer peripheral upstream surface 911a so as to smooth the corner where the inverter outer peripheral surface 910 and the inverter upstream surface 911 intersect. The flared upstream surface 911e is provided between the inverter outer peripheral surface 910 and the outer peripheral upstream surface 911a in the axial direction AD and the radial direction RD. The flared upstream surface 911e extends in the circumferential direction CD along the inverter outer peripheral surface 910 and the outer peripheral upstream surface 911a. The flared upstream surface 911e is inclined with respect to the inverter outer peripheral surface 910 and the outer peripheral upstream surface 911a. The flared upstream surface 911e is inclined with respect to the motor radial line Crd so as to face the outer periphery. The flared upstream surface 911e is a chamfered surface that chamfers the corner between the inverter outer peripheral surface 910 and the inverter upstream surface 911. The flared upstream surface 911 e forms the outer peripheral edge of the inverter upstream surface 911 .

[0125] The flare upstream surface 911e extends tapered toward the outer periphery. The flare upstream surface 911e is a tapered surface. The flare upstream surface 911e may be curved so as to bulge upstream or so as to be concave downstream. The flare upstream surface 911e may also be a curved surface or a bent surface.

[0126] The inverter upstream wall 96 has a flared upstream wall 96e. The flared upstream wall 96e forms a flared upstream surface 911e. The flared upstream surface 911e is the outer surface of the flared upstream wall 96e. The flared upstream wall 96e connects the inverter outer peripheral wall 95 and the outer peripheral upstream wall 96a so as to smooth the corner where the inverter outer peripheral wall 95 and the outer peripheral upstream wall 96a intersect. The flared upstream wall 96e is provided between the inverter outer peripheral wall 95 and the outer peripheral upstream wall 96a in the axial direction AD and the radial direction RD. The flared upstream wall 96e extends in the circumferential direction CD along the inverter outer peripheral wall 95 and the outer peripheral upstream wall 96a. The flared upstream wall 96e is inclined with respect to the inverter outer peripheral wall 95 and the outer peripheral upstream wall 96a.

[0127] In the inverter unit 170, at least a portion of the switch component 175 is disposed between the inclined upstream surface 911d and the flared upstream surface 911e in the radial direction RD. For example, the switch component 175 is disposed at a position spaced radially outward from the inclined upstream surface 911d. Alternatively, the switch component 175 is disposed at a position spaced radially inward from the flared upstream surface 911e. The capacitor component 176 and the filter component 177 are disposed at a position spaced radially inward from the inclined upstream surface 911d. Note that the switch component 175, the capacitor component 176, and the filter component 177 may be disposed in a position aligned with the inclined upstream surface 911d or the flared upstream surface 911e in the axial direction AD.

[0128] In the inverter fin 92, the axis-parallel portion 113 extends in the radial direction RD so as to bridge the inclined upstream surface 911d and the flared upstream surface 911e via the outer peripheral upstream surface 911a. For example, the axis-parallel portion 113 bridges the inner peripheral end of the inclined upstream surface 911d and the outer peripheral end of the flared upstream surface 911e. The axis-parallel portion 113 extends in the axial direction AD not only from the outer peripheral upstream surface 911a but also from the inclined upstream surface 911d and the flared upstream surface 911e. The extended parallel portion 114 extends in the axial direction AD from the outer peripheral parallel portion 112 toward the upstream side of the flare upstream surface 911e. The extended intersection portion 124 extends from the outer peripheral intersection portion 122 toward the upstream side of the flare upstream surface 911e.

[0129] The inverter upstream surface 911 has an inclined upstream surface 911d and a flared upstream surface 911e, so that the inner circumferential upstream surface 911b gradually bulges in the axial direction AD toward the upstream side. When the propeller winds Wp1 and Wp2 flow from the inner circumferential upstream surface 911b toward the outer circumferential upstream surface 911a, they flow along the inclined upstream surface 911d, which facilitates a gradual change in direction of travel. Therefore, when the propeller winds Wp1 and Wp2 pass through a step between the inner circumferential upstream surface 911b and the outer circumferential upstream surface 911a, the propeller winds Wp1 and Wp2 are prevented from separating from the outer circumferential upstream surface 911a, thereby preventing turbulence such as vortices from occurring in the propeller winds Wp1 and Wp2.

[0130] Furthermore, when the propeller winds Wp1 and Wp2 pass the outer peripheral upstream surface 911 a toward the outer periphery, they flow along the flare upstream surface 911 e, which makes it easy for them to change their direction of travel gradually. Therefore, when the propeller winds Wp1 and Wp2 pass the outer peripheral upstream surface 911 a toward the outer periphery, the propeller winds Wp1 and Wp2 are prevented from separating from the inverter outer peripheral surface 910, and from causing turbulence such as vortices in the propeller winds Wp1 and Wp2.

[0131] For example, consider a comparative example in which the inverter upstream surface 911 does not have a flare upstream surface 911e, unlike the present embodiment. In this comparative example, the propeller winds Wp1 and Wp2 tend to stagnate at the corner between the outer peripheral upstream surface 911a and the inverter outer peripheral surface 910. In contrast, in the present embodiment, the corner between the outer peripheral upstream surface 911a and the inverter outer peripheral surface 910 is chamfered by the flare upstream surface 911e, so the flare upstream surface 911e can prevent the propeller winds Wp1 and Wp2 from stagnating. This increases the inter-fin flow of the first propeller wind Wp1 and other winds flowing through the fin flow passage 130 compared to the comparative example. Furthermore, the thermal resistance in the inverter housing 90 can be reduced compared to the comparative example.

[0132] According to this embodiment, the inverter upstream surface 911 has an inclined upstream surface 911 d and a flared upstream surface 911 e. With this configuration, turbulence such as a vortex is less likely to occur in the propeller winds Wp1 and Wp2 when the propeller winds Wp1 and Wp2 flow along the inverter upstream surface 911. This makes it possible to prevent the cooling effect of the propeller winds Wp1 and Wp2 on the axis-parallel portion 113 from being reduced due to turbulence in the propeller winds Wp1 and Wp2.

[0133] Fourth Embodiment In the third embodiment, the inverter fins 92 are not provided on the inner circumferential upstream surface 911b. In contrast, in the fourth embodiment, at least a portion of the inverter fins 92 is provided on the inner circumferential upstream surface 911b. The configurations, actions, and effects of the fourth embodiment that are not specifically described are the same as those of the third embodiment. The fourth embodiment will be described mainly focusing on the differences from the third embodiment.

[0134] As shown in Figure 12, at least a portion of the axis-parallel portion 113 is provided on the inner peripheral upstream surface 911b. The axis-parallel portion 113 is bridged between the inner peripheral upstream surface 911b and the flared upstream surface 911e via the outer peripheral upstream surface 911a and the inclined upstream surface 911d. At least a portion of the axis-parallel portion 113 is provided in a position aligned with the capacitor component 176 and the filter component 177 in the axial direction AD. The axis-parallel portion 113 extends along the inverter upstream surface 911, more inward than the capacitor component 176 and the filter component 177. The axis-parallel portion 113 is bridged between the capacitor component 176, the filter component 177, and the switch component 175.

[0135] According to the present embodiment, the axis-parallel portion 113 is provided at a position aligned with the switch component 175, the capacitor component 176, and the filter component 177 in the axial direction AD, and at a position spanning all of the switch component 175, the capacitor component 176, and the filter component 177 in the radial direction RD. In this configuration, heat from each of the switch component 175, the capacitor component 176, and the filter component 177 is easily transferred to the axis-parallel portion 113. Therefore, the axis-parallel portion 113 can enhance the heat dissipation effect of the switch component 175, the capacitor component 176, and the filter component 177.

[0136] This embodiment may be applied to the first embodiment. For example, in a configuration in which the inverter upstream surface 911 does not have at least one of the inclined upstream surface 911d and the flared upstream surface 911e, at least a portion of the axis-parallel portion 113 may be provided in a position aligned with the capacitor component 176 and the filter component 177 in the axial direction AD. Furthermore, at least a portion of the axis-parallel portion 113 may be provided in a position aligned with at least one of the capacitor component 176 and the filter component 177 in the axial direction AD.

[0137] Fifth Embodiment In the third embodiment, the inverter fins 92 extend upstream beyond the inner circumferential upstream surface 911b. In contrast, in the fifth embodiment, the inverter fins 92 do not extend upstream beyond the inner circumferential upstream surface 911b. Configurations, operations, and effects not specifically described in the fifth embodiment are the same as those in the third embodiment. The fifth embodiment will be described mainly focusing on differences from the third embodiment.

[0138] 13 , in a configuration in which the inverter upstream surface 911 has an inclined upstream surface 911 d and a flared upstream surface 911 e, the axis-parallel portion 113 does not extend upstream beyond the inner circumferential upstream surface 911 b. Note that the axis-parallel portion 113 may be provided at a position downstream away from the inner circumferential upstream surface 911 b in the axial direction AD.

[0139] Sixth Embodiment In a sixth embodiment, a lightening portion is provided in the inverter fin 92. The configuration, operation, and effects of the sixth embodiment that are not specifically described are the same as those of the third embodiment. The sixth embodiment will be described mainly focusing on the differences from the third embodiment.

[0140] As shown in FIGS. 14 and 15 , the inverter fin 92 has a parallel recess 115. The parallel recess 115 is a recess provided in the parallel fin portion 111. The parallel recess 115 is formed by recessing the upstream end of the parallel fin portion 111 toward the downstream side. The parallel recess 115 is provided in at least a portion of the extended parallel portion 114. For example, the parallel recess 115 is provided in the upstream portion of the extended parallel portion 114. In the radial direction RD, the width dimension of the parallel recess 115 and the width dimension of the extended parallel portion 114 are approximately the same. The parallel recess 115 is provided at a position away from the inverter outer circumferential surface 910 toward the upstream side. The parallel recess 115 is provided between the axis-parallel portion 113 and the extended cross portion 124 in the radial direction RD. The parallel recess 115 is not provided in the outer circumferential parallel portion 112 or the axis-parallel portion 113. Furthermore, the parallel recess 115 is not provided in the cross fin portion 121.

[0141] The parallel recesses 115 are lightening portions for reducing the weight of the inverter fins 92. The parallel recesses 115 are provided in all of the inverter fins 92. The parallel recesses 115 are provided in the inverter fins 92 with a size, shape, and position that does not reduce the amount or speed of the first propeller wind Wp1 flowing through the fin flow passages 130. It is sufficient that the parallel recesses 115 are provided in at least one inverter fin 92. For example, inverter fins 92 provided with the parallel recesses 115 and inverter fins 92 not provided with the parallel recesses 115 may be arranged alternately in the circumferential direction CD.

[0142] According to the present embodiment, the parallel recess 115 is provided in at least a part of the extended intersection portion 124. With this configuration, the parallel recess 115 can reduce the weight of the inverter fins 92 while suppressing a decrease in the amount and speed of the first propeller wind Wp1 flowing through the fin flow path 130. In other words, the weight of the EPU 50 can be reduced while suppressing a decrease in the cooling effect of the inverter fins 92 on the inverter housing 90.

[0143] The extended parallel portion 114 is indirectly connected to the inverter housing main body 91 via the outer periphery parallel portion 112 and the axis parallel portion 113, and as a result, the extended parallel portion 114 is likely to have lower heat dissipation properties for releasing heat from the inverter housing main body 91 than the outer periphery parallel portion 112 and the axis parallel portion 113. In other words, the ease with which heat is transferred from the inverter housing main body 91 to the extended parallel portion 114 is likely to be lower than the ease with which heat is transferred from the inverter housing main body 91 to the outer periphery parallel portion 112 and the axis parallel portion 113. For this reason, even if the extended parallel portion 114 has the parallel recess 115, the degree of reduction in heat dissipation properties of the inverter fins 92 as a whole can be kept low.

[0144] The cutouts, such as the parallel recesses 115, may be provided anywhere in the inverter fins 92. For example, the cutouts may be provided in at least one of the parallel fin section 111 and the cross fin section 121. In the parallel fin section 111, the cutouts may be provided in at least a part of the outer circumferential parallel section 112, the axial parallel section 113, and the extended parallel section 114. The cutouts are preferably provided in the inverter fins 92 so as not to reduce the cooling effect of the inverter fins 92. The cutouts may be formed as holes that penetrate the inverter fins 92 in the thickness direction, grooves that extend along the plate surfaces of the inverter fins 92, or the like.

[0145] Seventh Embodiment In the first embodiment, the cross fin portions 121, which are portions of the inverter fins 92 that extend in the circumferential direction CD, form the outer periphery limiting portions. In contrast, in the seventh embodiment, the portions of the inverter fins 92 that extend in the radial direction RD form the outer periphery limiting portions. Configurations, actions, and effects that are not specifically described in the seventh embodiment are the same as those in the third embodiment. The seventh embodiment will be described mainly with reference to differences from the third embodiment.

[0146] 16 and 17 , the inverter fin 92 has an extended fin portion 201. The extended fin portion 201 forms the entire inverter fin 92. The extended fin portion 201 extends in the axial direction AD so as to straddle the upstream end of the inverter outer peripheral surface 910. The extended fin portion 201 extends in the axial direction AD along the inverter outer peripheral surface 910 and protrudes from the inverter outer peripheral surface 910 toward the upstream side.

[0147] The expandable fin section 201 extends in the radial direction RD along the motor radial line Crd. The expandable fin section 201 is formed in a plate shape and extends in a direction perpendicular to the circumferential direction CD. The expandable fin section 201 has a shape that gradually expands in the circumferential direction CD toward the outer periphery. The expandable fin section 201 continuously expands toward the outer periphery. The expandable fin section 201 is formed in a tapered shape.

[0148] The width dimension D11 of the expandable fin section 201 gradually increases toward the outer periphery. In the expandable fin section 201, the portion with the largest width dimension D11 is the outer periphery end. In the expandable fin section 201, the portion with the smallest width dimension D11 is the inner periphery end. The width dimension D11a of the outer periphery end is larger than the width dimension D11b of the inner periphery end. The width dimension D11a of the outer periphery end is the width dimension of the expanded tip surface 201b.

[0149] The expandable fin section 201 has a pair of fin extension surfaces 201a. The fin extension surfaces 201a are plate surfaces of the expandable fin section 201. The fin extension surfaces 201a extend in a direction perpendicular to the circumferential direction CD. The pair of fin extension surfaces 201a are aligned in the circumferential direction CD. The fin extension surfaces 201a are inclined in the circumferential direction CD with respect to the motor radial line Crd. The expandable fin section 201 intersects with the motor radial line Crd. The fin extension surfaces 201a are tapered surfaces. The expandable fin section 201 may be expanded in stages toward the outer periphery. For example, the fin extension surfaces 201a may be stepped surfaces. The fin extension surfaces 201a may be curved so as to bulge in the circumferential direction CD or so as to be concave in the circumferential direction CD. The fin extension surfaces 201a may be curved or bent surfaces.

[0150] The expandable fin section 201 has an expanded tip surface 201b. The expanded tip surface 201b is the tip surface of the expandable fin section 201. The expanded tip surface 201b faces the outer periphery. The expanded tip surface 201b is disposed across the pair of fin expansion surfaces 201a in the circumferential direction CD.

[0151] The expanding fin section 201 has a peripheral expanding section 202, an axial expanding section 203, and an extended expanding section 204. The peripheral expanding section 202 is a portion of the expanding fin section 201 that extends from the inverter peripheral surface 910 toward the outer periphery. The peripheral expanding section 202 extends in the axial direction AD along the inverter peripheral surface 910. The peripheral expanding section 202 corresponds to the peripheral fin section and the peripheral limiting section. The peripheral expanding section 202 spans between the upstream end and downstream end of the inverter peripheral surface 910. At least a portion of the peripheral expanding section 202 is provided in a position aligned with the switch component 175 in the radial direction RD.

[0152] The axial expansion portion 203 is a portion of the expansion fin portion 201 that extends from the inverter upstream surface 911 in the axial direction AD. The axial expansion portion 203 extends in the radial direction RD along the inverter upstream surface 911. The axial expansion portion 203 corresponds to a axial fin portion. The axial expansion portion 203 is provided on the outer peripheral upstream surface 911a, the inclined upstream surface 911d, and the flared upstream surface 911e so as to extend from the outer peripheral upstream surface 911a in the axial direction AD. The axial expansion portion 203 extends in the radial direction RD along at least one of the outer peripheral upstream surface 911a, the inclined upstream surface 911d, and the flared upstream surface 911e. The axial parallel portion 113 spans between the inner peripheral end of the inclined upstream surface 911d and the outer peripheral end of the flared upstream surface 911e.

[0153] At least a portion of the axial expansion portion 203 is provided in a position aligned with the switch component 175 in the axial direction AD. For example, the axial expansion portion 203 is provided in a position aligned with the switch component 175 in the axial direction AD and straddling the switch component 175 in the radial direction RD. The switch component 175 is provided between the outer peripheral end and the inner peripheral end of the axial expansion portion 203 in the radial direction RD.

[0154] The extended extension portion 204 is a portion of the expandable fin portion 201 that connects the outer circumferential extension portion 202 and the axial extension portion 203. The extended extension portion 204 extends in the axial direction AD from the outer circumferential extension portion 202 toward the upstream side of the inverter outer circumferential surface 910. The extended extension portion 204 also extends from the axial extension portion 203 toward the outer circumferential side of the inverter outer circumferential surface 910. The extended extension portion 204 corresponds to an outer circumferential extension portion and an outer circumferential limiting portion. The extended extension portion 204 spans between the inner circumferential end and the outer circumferential end of the outer circumferential extension portion 202 in the radial direction RD. The extended extension portion 204 also spans between the upstream end and the downstream end of the axial extension portion 203 in the axial direction AD.

[0155] The expanding fin portion 201 has a peripheral expansion portion 202 and an extension expansion portion 204, and is therefore included in both the peripheral fin portion and the peripheral extension portion. The expanding fin portion 201 extends in the axial direction AD, straddling the boundary between the peripheral fin portion and the peripheral extension portion. In other words, the peripheral expansion portion 202 and the extension expansion portion 204 as a whole extend in the axial direction AD, straddling the boundary between the peripheral fin portion and the peripheral extension portion. The boundary between the peripheral expansion portion 202 and the extension expansion portion 204 corresponds to the boundary between the peripheral fin portion and the peripheral extension portion.

[0156] The fin flow path 130 is formed by two adjacent extended fin portions 201 in the circumferential direction CD. The fin flow path 130 is formed between two fin extended surfaces 201a that face each other in the circumferential direction CD. The fin upstream port 131 is formed by the inner circumferential edge and upstream edge of the fin extended surface 201a. The fin downstream port 132 is formed by the downstream edge of the fin extended surface 201a. The fin outer peripheral port 133 is formed by the outer circumferential edge of the fin extended surface 201a. The fin outer peripheral port 133 is formed between two adjacent extended tip surfaces 201b in the circumferential direction CD.

[0157] The fin flow channels 130 have a shape that gradually narrows in the circumferential direction CD toward the outer periphery. The fin flow channels 130 narrow continuously toward the outer periphery. The width dimension D12 of the fin flow channels 130 in the circumferential direction CD gradually decreases toward the outer periphery. The width dimension D12 is the distance between two fin extension surfaces 201a that face each other in the circumferential direction CD. In the fin flow channels 130, the portion with the largest width dimension D12 is the outer periphery end. In the fin flow channels 130, the portion with the smallest width dimension D12 is the inner periphery end. The width dimension D12a at the outer periphery end is smaller than the width dimension D12b at the inner periphery end. The width dimension D12a at the outer periphery end is the distance between two extension tip surfaces 201b that are adjacent in the circumferential direction CD.

[0158] The propeller wind Wp includes a third propeller wind Wp3. The third propeller wind Wp3 flows from the fin upstream port 131 into the fin flow path 130 by flowing toward the outer periphery along the inverter upstream surface 911, and then flows through the fin flow path 130 along the fin extension surface 201a toward the outer periphery. Because the fin flow path 130 gradually narrows toward the outer periphery, the fin extension surface 201a restricts the third propeller wind Wp3 from passing through the fin flow path 130 toward the outer periphery. Therefore, when the third propeller wind Wp3 passes toward the outer periphery of the inverter outer periphery surface 910, it is guided by the fin extension surface 201a to flow downstream through the fin flow path 130. The third propeller wind Wp3 flows downstream through the fin flow path 130 and flows out from the fin downstream port 132. The fin extension surface 201a restricts the third propeller wind Wp3 from flowing out toward the outer periphery from the fin outer periphery port 133. The third propeller wind Wp3 is guided in the axial direction AD by the fin extension surface 201a, so that heat is easily released from the extension fin portion 201 and the inverter outer peripheral surface 910 to the third propeller wind Wp3.

[0159] According to this embodiment, in the expansion fin section 201, the pair of fin expansion surfaces 201a gradually expand the width of the inverter fins 92 in the circumferential direction CD toward the outer periphery. In this configuration, the pair of fin expansion surfaces 201a gradually narrow the fin flow paths 130 toward the outer periphery. Therefore, the expansion fin section 201 can restrict the third propeller wind Wp3 from flowing through the inverter fins 92 toward the outer periphery.

[0160] Eighth Embodiment In an eighth embodiment, the width dimension D2 of the fin outer peripheral opening 133 may be set according to the distance between two adjacent parallel fin portions 111 in the circumferential direction CD. The configurations, actions, and effects of the eighth embodiment that are not specifically described are the same as those of the first embodiment. The eighth embodiment will be described mainly focusing on the differences from the first embodiment.

[0161] 18 , the cross fin portion 121 has a cross tip surface 121c. The cross tip surface 121c is the tip surface of the cross fin portion 121. The cross tip surface 121c extends in a direction perpendicular to the circumferential direction CD. Of the inverter fins 92 adjacent to each other in the circumferential direction CD, the cross tip surface 121c of one of the inverter fins 92 faces the fin parallel surface 111a of the other inverter fin 92 across the fin outer peripheral opening 133.

[0162] The distance between two adjacent inverter fins 92 in the circumferential direction CD varies depending on their position in the radial direction RD. For example, the width dimension D2 of the fin outer peripheral opening 133 is smaller than the distance D3 at the inverter outer peripheral surface 910 between two adjacent parallel fin portions 111 in the circumferential direction CD. The width dimension D2 is the distance between one fin parallel surface 111a and the other intersecting tip surface 121c of two adjacent inverter fins 92 in the circumferential direction CD. The width dimension D2 corresponds to the opening distance. The distance D3 is also the distance at the inverter outer peripheral surface 910 between two adjacent axial parallel portions 113 in the circumferential direction CD. The distance D3 is also the distance at the base ends of adjacent outer peripheral parallel portions 112 in the circumferential direction CD. The distance D3 corresponds to the outer peripheral surface distance.

[0163] The fin flow path 130 includes an outer circumferential path 130a. The outer circumferential path 130a is a region of the fin flow path 130 formed on the outer circumferential side of the inverter outer circumferential surface 910. The outer circumferential path 130a is a flow path between two axis-parallel portions 113 adjacent in the circumferential direction CD, and is also a region between the inverter outer circumferential surface 910 and the fin intersection inner surface 121b in the radial direction RD. The outer circumferential path 130a extends in the axial direction AD to span between the fin upstream port 131 and the fin downstream port 132. The outer circumferential path cross-sectional area S1 of the outer circumferential path 130a has a value corresponding to the distance D3. The outer circumferential path cross-sectional area S1 is the cross-sectional area of ​​the outer circumferential path 130a cut in a direction perpendicular to the axial direction AD. The outer circumferential path cross-sectional area S1 is approximately the same as the downstream port area S132.

[0164] The outer peripheral path cross-sectional area S1 has a value corresponding to the distance D3 as well as the extension dimension L1 of the parallel fin portion 111. The extension dimension L1 is the length by which the parallel fin portion 111 extends from the inverter outer peripheral surface 910 toward the outer periphery. The extension dimension L1 is also the length by which the extended parallel portion 114 extends from the inverter outer peripheral surface 910 toward the outer periphery. The extension dimension L1 is also the length by which the outer peripheral parallel portion 112 extends from the inverter outer peripheral surface 910 toward the outer periphery. In the outer peripheral path 130a, the greater the extension dimension L1, the larger the outer peripheral path cross-sectional area S1.

[0165] The heat dissipation performance Pd [W / K] of the inverter fins 92 is likely to be determined according to the opening ratio Ro. The heat dissipation performance Pd is the ability of the inverter fins 92 to dissipate heat to the outside from the fin outer peripheral opening 133. The larger the heat dissipation performance Pd, the more easily the heat of the inverter fins 92 is dissipated to the outside from the fin outer peripheral opening 133 by the propeller winds Wp1, Wp2, etc. The heat dissipation performance Pd per unit area is determined by the heat transfer coefficient [W / m ２ It is sometimes referred to as K.

[0166] The open ratio Ro is the ratio of the distance D3 to the width dimension D2. In the outer peripheral passage 130a, the heat dissipation performance Pd is likely to be high when the open ratio Ro is within the allowable range. For example, as shown in FIG. 19 , the heat dissipation performance Pd is likely to be high when the open ratio Ro is in the range of 0.1 or more and 0.3 or less. In this configuration, the allowable range for the open ratio Ro is 0.1 or more and 0.3 or less. From the perspective of increasing the heat dissipation performance Pd, it is preferable that the open ratio Ro be in the range of 0.15 or more and 0.25 or less. Furthermore, it is preferable that the open ratio Ro is approximately 0.2. Note that a configuration in which the open ratio Ro is approximately 0.2 includes configurations in which the open ratio Ro is slightly higher or lower than 0.2.

[0167] In a configuration in which the opening ratio Ro is within the allowable range, the balance between the flow rate and flow velocity of the propeller wind Wp in the fin flow passage 130 is good, which tends to increase the heat dissipation performance Pd. As shown in FIG. 18 , the first propeller wind Wp1 flowing along the fin parallel surfaces 111a flows toward the outer periphery and exits through the fin outer peripheral opening 133. In this case, the first propeller wind Wp1 flows along the fin parallel surfaces 111a, which tends to increase the flow velocity of the first propeller wind Wp1. Furthermore, the second propeller wind Wp2 flowing toward the cross fin section 121 can exit through the fin outer peripheral opening 133 by changing direction in the circumferential direction CD as it approaches the fin cross inner surface 121b. In this case, the flow rate of the second propeller wind Wp2 exiting through the fin outer peripheral opening 133 is unlikely to be insufficient. In this way, the first propeller wind Wp1 and the second propeller wind Wp2 improve the balance between the flow velocity and the volume of the propeller wind Wp in the fin flow path 130. Note that in Fig. 18, the longer the arrows for the propeller winds Wp1 and Wp2, the faster the flow velocity.

[0168] For example, unlike this embodiment, in a configuration in which the opening ratio Ro is smaller than the allowable range, the heat dissipation performance Pd is likely to decrease due to a small flow rate of the propeller wind Wp, etc. Also, unlike this embodiment, in a configuration in which the opening ratio Ro is larger than the allowable range, the heat dissipation performance Pd is likely to decrease due to a slow flow velocity of the propeller wind Wp, etc.

[0169] In the fin flow path 130, the larger the outer peripheral path cross-sectional area S1, the higher the heat dissipation performance Pd. For example, as shown in FIG. 19 , consider a first configuration in which the outer peripheral path cross-sectional area S1 is a first area Sa, a second configuration in which the outer peripheral path cross-sectional area S1 is a second area Sb, and a third configuration in which the outer peripheral path cross-sectional area S1 is a third area Sc. Of the areas S1 to Sc, the first area Sa is the largest and the third area Sc is the smallest. For example, the second area Sb is twice the third area Sc, and the first area Sa is three times the third area Sc. The first, second, and third configurations have different extension dimensions L1, which results in different outer peripheral path cross-sectional areas S1.

[0170] In the first, second, and third configurations, the heat dissipation performance Pd for the first area Sa is likely to be highest, and the heat dissipation performance Pd for the third area Sc is likely to be lowest. In the first configuration, the opening ratio Ro at which the heat dissipation performance Pd is highest is closer to the lower limit than the upper limit in the allowable range. In the third configuration, the opening ratio Ro at which the heat dissipation performance Pd is highest is closer to the upper limit than the lower limit in the allowable range.

[0171] According to the present embodiment, the opening ratio Ro is within a range of 0.1 or more and 0.3 or less. With this configuration, it is easy to balance the flow rate and flow velocity of the propeller wind Wp flowing between two inverter fins 92 adjacent to each other in the circumferential direction CD. By balancing the flow rate and flow velocity of the propeller wind Wp in this manner, the heat dissipation performance Pd of the inverter fins 92 can be improved.

[0172] In this embodiment, the width dimension D2, which is the distance between the fins at the fin outer peripheral opening 133, is smaller than the distance D3, which is the distance between the fins at the inverter outer peripheral surface 910. Therefore, the flow velocity of the airflow, such as the propeller wind Wp, flowing out of the fin outer peripheral opening 133 tends to be larger than the flow velocity of the airflow flowing between the fins near the inverter outer peripheral surface 910. As a result, the amount of heat dissipated from the inverter fins 92 around the fin outer peripheral opening 133 tends to be larger than the amount of heat dissipated from the inverter fins 92 in other parts. Therefore, it is possible to improve the heat dissipation performance of the inverter fins 92 around the fin outer peripheral opening 133.

[0173] For example, consider a comparative example in which, unlike the present embodiment, the fin outer peripheral opening 133 is completely closed by the inverter fins 92, resulting in a width dimension D2 of zero. In the comparative example, the heat dissipation performance Pd is likely to decrease because the airflow is less likely to flow out from the fin flow passages 130 to the outer periphery. In contrast, in the present embodiment, the heat dissipation performance Pd is likely to improve because the airflow flows out from the fin outer peripheral opening 133 to the outer periphery.

[0174] In the inverter housing 90, the width dimension D2 of the fin outer peripheral opening 133 that must be secured to obtain optimal heat dissipation performance Pd varies depending on the size of the fin downstream opening 132, which is the open opening on the outflow side, and the size of the outer peripheral path cross-sectional area S1. For the inverter housing 90, it is preferable to set the width dimension D2 and the distance D3 so that the opening ratio Ro is about 0.2.

[0175] For refrigerants such as propeller wind Wp, the motor device 60 is mounted downstream of the inverter device 80. In the EPU 50, heat must be dissipated not only from the inverter housing 90 but also from the motor housing 70. For the refrigerant flowing through the outer peripheral passage 130a, by making the outflow rate from the fin downstream port 132 greater than the outflow rate from the fin outer peripheral port 133, the outflow rate from the fin outer peripheral port 133 tends to be smaller and the outflow rate from the fin downstream port 132 tends to be larger. Increasing the outflow rate from the fin downstream port 132 improves the effectiveness of the refrigerant in cooling the motor device 60.

[0176] Furthermore, when the width dimension D2 of the fin outer peripheral opening 133 is appropriately set, the outflow rate from the fin outer peripheral opening 133 is easily suppressed and the flow rate of the refrigerant flowing out from the fin outer peripheral opening 133 is easily increased. In this way, the flow rate of the refrigerant is increased to the extent that the flow rate of the refrigerant flowing through the fin flow passages 130 is not insufficient, thereby improving the heat dissipation performance Pd in ​​the fin gaps.

[0177] Ninth Embodiment In a ninth embodiment, a heat dissipation fin different from the inverter fins 92 may be provided between two inverter fins 92 adjacent to each other in the circumferential direction CD. The configurations, actions, and effects of the ninth embodiment that are not specifically described are the same as those of the first embodiment. The ninth embodiment will be described mainly with reference to differences from the first embodiment.

[0178] As shown in FIG. 20 , the inverter housing 90 has intervening fins 221. The intervening fins 221 are made of a metal material or the like and have thermal conductivity. Like the inverter fins 92, the intervening fins 221 are provided on the outer surface of the inverter housing 90. The intervening fins 221 are heat dissipation fins for dissipating heat from the inverter device 80 to the outside. The intervening fins 221 extend from the outer surface of the inverter housing 90 in a direction perpendicular to the circumferential direction CD. The intervening fins 221 are provided on the inverter upstream surface 911. The intervening fins 221 extend from the inverter upstream surface 911 in the axial direction AD. The intervening fins 221 also extend in the radial direction RD along the inverter upstream surface 911.

[0179] Unlike the inverter fins 92, the intervening fins 221 do not have a portion corresponding to an outer periphery limiting portion such as the cross fin portion 121. Like the parallel fin portion 111, the intervening fins 221 extend in the radial direction RD along the motor radial line Crd. The intervening fins 221 extend parallel to the motor radial line Crd. The intervening fins 221 are formed in a plate shape and extend in a direction perpendicular to the circumferential direction CD.

[0180] The intervening fin 221 has a pair of intervening surfaces 221a. The intervening surfaces 221a are plate surfaces of the intervening fin 221. The intervening surfaces 221a extend in a direction perpendicular to the circumferential direction CD. The pair of intervening surfaces 221a are aligned in the circumferential direction CD. The pair of intervening surfaces 221a extend parallel to each other. Furthermore, the pair of intervening surfaces 221a extend parallel to the motor radial line Crd. The intervening fin 221 has an intervening tip surface 221b. The intervening tip surface 221b is the tip surface of the intervening fin 221. The intervening tip surface 221b faces the outer circumferential side.

[0181] Each intervening fin 221 is provided between two adjacent inverter fins 92 in the circumferential direction CD. A plurality of intervening fins 221 are arranged in the circumferential direction CD. The inverter fins 92 and the intervening fins 221 are arranged alternately in the circumferential direction CD.

[0182] The intervening fins 221 are provided at positions aligned in the radial direction RD at the fin outer peripheral opening 133. The intervening fin 221 is provided between one intersecting tip surface 121c and the other fin parallel surface 111a of two inverter fins 92 adjacent to each other in the circumferential direction CD. The intervening fin 221 is in a state of being sandwiched between the intersecting tip surface 121c and the fin parallel surface 111a. For example, the intervening tip surface 221b is provided between the intersecting tip surface 121c and the fin parallel surface 111a in the circumferential direction CD. The intervening tip surface 221b is also provided between the fin intersecting outer surface 121a and the fin intersecting inner surface 121b in the radial direction RD. The intervening fin 221 does not protrude radially outward beyond the inverter fins 92.

[0183] 20 and 21 , the interposed fin 221 extends in the radial direction RD so as to span between the outer peripheral upstream surface 911 a and the inner peripheral upstream surface 911 b. The interposed fin 221 extends in the axial direction AD from each of the outer peripheral upstream surface 911 a and the inner peripheral upstream surface 911 b. The interposed fin 221 extends further in the axial direction AD than the inverter fins 92.

[0184] The intervening fin 221 has an axial intervening portion 223 and an extended intervening portion 224. The axial intervening portion 223 is a portion of the intervening fin 221 that extends from the inverter upstream surface 911 in the axial direction AD. The axial intervening portion 223 extends in the axial direction AD and the radial direction RD along the axial parallel portion 113. The extended intervening portion 224 is a portion of the intervening fin 221 that extends from the axial intervening portion 223 toward the outer periphery. The extended intervening portion 224 protrudes toward the outer periphery beyond the inverter outer periphery surface 910. The extended intervening portion 224 extends in the radial direction RD along the extended parallel portion 114. Note that the intervening fin 221 may have a portion that extends from the inverter outer periphery surface 910 toward the outer periphery.

[0185] According to the present embodiment, the intervening fin 221 does not have a portion corresponding to the outer periphery limiting portion, and is provided between two inverter fins 92 adjacent in the circumferential direction CD. In this configuration, even if the width dimension D2 of the fin outer periphery opening 133 between two inverter fins 92 adjacent in the circumferential direction CD is too large, the intervening fin 221 can adjust the flow rate and flow velocity of the propeller wind Wp flowing out from the fin outer periphery opening 133. Therefore, the intervening fin 221 can improve the balance between the flow rate and flow velocity of the propeller wind Wp flowing between two inverter fins 92 adjacent in the circumferential direction CD.

[0186] Furthermore, in the inverter housing 90, heat can be dissipated not only by the inverter fins 92 but also by the intervening fins 221. Therefore, the heat dissipation effect of the inverter housing 90 can be improved by both the inverter fins 92 and the intervening fins 221.

[0187] Tenth Embodiment In a tenth embodiment, at least a portion of the inverter device 80 may be housed in a duct member. Configurations, actions, and effects not specifically described in the tenth embodiment are the same as those in the first embodiment. The tenth embodiment will be described focusing on differences from the first embodiment.

[0188] As shown in FIGS. 22 to 24 , the EPU 50 has an outer circumferential duct 240. The outer circumferential duct 240 is formed into a cylindrical shape including a cylindrical member and extends in the axial direction AD. The outer circumferential duct 240 is formed from a resin material or the like. The outer circumferential duct 240 may also be referred to as an outer cylinder or an outer cylinder member. The outer circumferential duct 240 houses at least a portion of the inverter housing 90. The outer circumferential duct 240 covers the inverter outer peripheral surface 910 from the outer periphery. The outer circumferential duct 240 is fixed to the inverter housing 90 with fasteners such as bolts.

[0189] The inverter housing 90 has intra-duct fins 231. The intra-duct fins 231 have the same configuration as the parallel fin section 111 of the first embodiment. That is, the intra-duct fins 231 have substantially the same configuration as the inverter fins 92 of the first embodiment, which do not have the cross fin section 121. The intra-duct fins 231 do not have a portion corresponding to an outer periphery limiting section. The intra-duct fins 231 are housed in the outer periphery duct 240 together with the inverter housing main body 91.

[0190] The duct interior fins 231 are made of a metal material or the like and have thermal conductivity. Like the inverter fins 92, the duct interior fins 231 are provided on the outer surface of the inverter housing 90. The duct interior fins 231 are heat dissipation fins for dissipating heat from the inverter device 80 to the outside. The duct interior fins 231 extend from the outer surface of the inverter housing 90 in a direction perpendicular to the circumferential direction CD. A plurality of the duct interior fins 231 are arranged in the circumferential direction CD. The duct interior fins 231 correspond to the peripheral fins and the axial fins.

[0191] The inner-duct fin 231 has an outer periphery parallel portion 232, an axial parallel portion 233, and an extended parallel portion 234. The outer periphery parallel portion 232, the axial parallel portion 233, and the extended parallel portion 234 correspond to the outer periphery parallel portion 112, the axial parallel portion 113, and the extended parallel portion 114 of the first embodiment. The outer periphery parallel portion 232, the axial parallel portion 233, and the extended parallel portion 234 have the same configurations as the outer periphery parallel portion 112, the axial parallel portion 113, and the extended parallel portion 114, respectively. The outer periphery parallel portion 232 corresponds to the outer periphery fin portion. The axial parallel portion 233 corresponds to the axial fin portion. The extended parallel portion 234 corresponds to the outer periphery extended portion and the axial extended portion.

[0192] The fin flow path 130 is formed between two adjacent in-duct fins 231 in the circumferential direction CD. The fin upstream port 131, the fin downstream port 132, and the fin outer peripheral port 133 are formed between two adjacent in-duct fins 231 in the circumferential direction CD. The fin outer peripheral port 133 extends in the axial direction AD to bridge between the outer peripheral parallel portion 232 and the extended parallel portion 234.

[0193] The outer duct 240 is provided on the outer peripheral side of the inverter outer surface 910 via the inner duct fins 231. The outer duct 240 covers at least a portion of the inner duct fins 231 from the outer peripheral side. The tips of the inner duct fins 231 contact the inner peripheral surface of the outer duct 240. The outer duct 240 extends in the axial direction AD so as to span between the outer periphery parallel portion 232 and the extended parallel portion 234.

[0194] 25 , the outer periphery duct 240 has a first end face 240 a and a second end face 240 b. The outer periphery duct 240 has a pair of end faces aligned in the axial direction AD. One of the pair of end faces 240 b is the first end face 240 a, and the other is the second end face 240 b.

[0195] Slits 241 are formed in the outer circumferential duct 240. The slits 241 penetrate the outer circumferential duct 240 in the radial direction RD to allow ventilation. A plurality of the slits 241 are arranged in the circumferential direction CD. The slits 241 are notches extending from the second end face 240b toward the first end face 240a. The slits 241 are also recesses provided in the second end face 240b. The slits 241 correspond to ventilation sections.

[0196] The outer circumferential duct 240 has an annular wall 242 and an extending wall 243. The annular wall 242 extends annularly in the circumferential direction CD. The annular wall 242 is formed in a ring shape. The annular wall 242 is sometimes referred to as a ring-shaped portion. The annular wall 242 forms a first end surface 240a. The extending wall 243 extends from the annular wall 242 in the axial direction AD. The extending wall 243 forms a second end surface 240b. A plurality of extending walls 243 are arranged in the circumferential direction CD. The annular wall 242 connects the plurality of extending walls 243 by spanning across them. Two extending walls 243 adjacent to each other in the circumferential direction CD are spaced apart from each other in the circumferential direction CD. The space between two extending walls 243 adjacent to each other in the circumferential direction CD is a slit portion 241. In the axial direction AD, the length dimension of the extending wall 243 is greater than the length dimension of the annular wall 242. Note that the length dimension of the extending wall 243 does not have to be greater than the length dimension of the annular wall 242.

[0197] 22 , the outer circumferential duct 240 is attached to the inverter housing 90 so that the first end face 240a faces the upstream side of the propeller wind Wp. In the outer circumferential duct 240, the first end face 240a and the annular wall 242 are disposed on the inverter upstream wall 96 side in the axial direction AD, and the second end face 240b and the extending wall 243 are disposed on the inverter downstream wall 97 side. The slit portion 241 opens toward the downstream side of the propeller wind Wp. The extending wall 243 and the slit portion 241 are located downstream of the annular wall 242 with respect to the propeller wind Wp.

[0198] 22 and 23 , at least a portion of the annular wall 242 is aligned with the axially parallel portion 233 and the extending parallel portion 234 in the radial direction RD. The annular wall 242 spans two adjacent extending parallel portions 234 in the circumferential direction CD. The annular wall 242 covers the fin outer peripheral opening 133 from the outer circumferential side. The annular wall 242 restricts the propeller wind Wp flowing through the fin flow passage 130 from passing through the fin outer peripheral opening 133 toward the outer circumferential side. The annular wall 242 corresponds to a duct restricting portion.

[0199] As shown in FIGS. 22 and 24 , the extension wall 243 is provided on the outer circumferential side of the outer circumferential parallel portion 232. The extension wall 243 is positioned offset in the circumferential direction CD from the outer circumferential parallel portion 232. For example, the extension wall 243 is provided between two outer circumferential parallel portions 232 adjacent in the circumferential direction CD. The extension wall 243 is positioned so as to be aligned with at least a portion of the fin outer circumferential opening 133 in the radial direction RD. For example, the extension wall 243 blocks a portion of the fin outer circumferential opening 133. A gap is formed between the extension wall 243 and the outer circumferential parallel portion 232. In the fin flow path 130, the propeller wind Wp flows outward through the gap between the extension wall 243 and the outer circumferential parallel portion 232 of the fin outer circumferential opening 133. In other words, the extension wall 243 restricts the propeller wind Wp from passing through the fin outer circumferential opening 133 toward the outer circumferential side. The extension wall 243 corresponds to a duct restricting portion.

[0200] According to this embodiment, in the in-duct fins 231, the extended parallel portions 234 extend in the axial direction AD from the outer circumferential parallel portions 232 beyond the inverter outer circumferential surface 910. With this configuration, the propeller wind Wp flowing in the axial direction AD toward the inverter housing 90 tends to flow along the extended parallel portions 234 when it avoids the inverter housing 90 and expands toward the outer circumferential side. Therefore, the extended parallel portions 234 can enhance the heat dissipation effect of the in-duct fins 231.

[0201] Moreover, in the outer circumferential duct 240, the annular wall 242 and the extending wall 243 restrict the propeller wind Wp from flowing toward the outer periphery between two adjacent inner-duct fins 231 in the circumferential direction CD. In this configuration, between two adjacent inner-duct fins 231 in the circumferential direction CD, the propeller wind Wp flowing toward the outer periphery is guided by the annular wall 242 and the extending wall 243 so as to flow in the axial direction AD along the inverter outer circumferential surface 910. This makes it easy for the propeller wind Wp flowing along the outer periphery parallel portion 232 and the extending parallel portion 234 to increase. Therefore, the heat dissipation effect of the outer periphery parallel portion 232 can be enhanced by the annular wall 242 and the extending wall 243.

[0202] As described above, the heat dissipation effect of the inverter housing 90 in the EPU 50 can be improved by the inner duct fins 231 and the outer peripheral duct 240 .

[0203] According to this embodiment, the annular wall 242 and the extending wall 243 are provided so that the fin flow path 130, which is the space between two adjacent in-duct fins 231 in the circumferential direction CD, is open to the outer circumferential side through the slit portion 241. In this configuration, the degree of restriction by the annular wall 242 and the extending wall 243 to restrict the outflow of the propeller wind Wp can be adjusted by adjusting the degree of communication between the fin flow path 130 and the slit portion 241. This makes it possible to improve the balance between the flow rate and flow velocity of the propeller wind Wp flowing out from the slit portion 241. Therefore, the annular wall 242 and the extending wall 243 can improve the heat dissipation performance of the in-duct fins 231.

[0204] According to this embodiment, the outer periphery duct 240 is attached to the inverter housing 90 with the slit portion 241 aligned in the radial direction RD with the outer periphery parallel portion 232 and the extended parallel portion 234. In this configuration, the annular wall 242 prevents the propeller wind Wp flowing toward the outer periphery along the axis parallel portion 233 from flowing outward from the outer periphery duct 240 without flowing in the axial direction AD along the inverter outer periphery surface 910 or the outer periphery parallel portion 232. For example, as shown in FIG. 22 , the second propeller wind Wp2 flowing toward the outer periphery along the axis parallel portion 233 is guided by the annular wall 242 to flow in the axial direction AD. Therefore, the second propeller wind Wp2 is more likely to flow in the axial direction AD along the inverter outer periphery surface 910 and the outer periphery parallel portion 232. Therefore, the heat dissipation effect of the inverter outer periphery surface 910 and the outer periphery parallel portion 232 can be enhanced by the second propeller wind Wp2.

[0205] According to this embodiment, in the in-duct fins 231, the extended parallel portions 234 extend from the axially parallel portions 233 toward the outer periphery of the inverter outer periphery 910. With this configuration, when the propeller wind Wp flowing in the axial direction AD toward the inverter housing 90 avoids the inverter housing 90 and expands toward the outer periphery, it is likely to flow along the axially parallel portions 233 and the extended parallel portions 234. Therefore, the axially parallel portions 233 and the extended parallel portions 234 can enhance the heat dissipation effect of the in-duct fins 231.

[0206] Moreover, the propeller wind Wp that flows toward the outer periphery along the axially parallel portion 233 and the extended parallel portion 234 is guided by the annular wall 242 and the extending wall 243 so as to flow in the axial direction AD along the inverter outer periphery surface 910. In this way, the propeller wind Wp that flows along the inverter outer periphery surface 910 is likely to increase, and the heat dissipation effect of the inverter outer periphery surface 910 can be improved by the annular wall 242 and the extending wall 243.

[0207] In the present embodiment, the degree of communication between the fin outer peripheral opening 133 and the slit portion 241 can be adjusted by adjusting the width dimension of the slit portion 241 in the circumferential direction CD. For example, the larger the width dimension of the slit portion 241, the greater the flow rate of the propeller wind Wp flowing out from the fin outer peripheral opening 133 to the outer periphery through the slit portion 241. On the other hand, the smaller the width dimension of the slit portion 241, the greater the flow velocity of the propeller wind Wp flowing out from the fin outer peripheral opening 133 to the outer periphery through the slit portion 241. Therefore, by adjusting the width dimension of the slit portion 241, it is possible to appropriately set the balance between the flow rate and flow velocity of the propeller wind Wp flowing out from the fin outer peripheral opening 133 through the slit portion 241.

[0208] In this embodiment, an annular wall 242 is provided on the extended parallel portion 234 out of the outer peripheral parallel portion 232 and the extended parallel portion 234. This configuration can prevent refrigerant such as propeller wind Wp from passing through the extended parallel portion 234 to the outer periphery and leaking outward from the fin outer peripheral opening 133. Furthermore, this configuration guides the refrigerant downstream by the annular wall 242, making it possible to increase the amount of refrigerant supplied to the motor device 60 mounted downstream of the inverter device 80.

[0209] The weight of the EPU 50 of this embodiment is increased compared to the EPU 50 of the first embodiment by the weight of the outer duct 240, but is reduced compared to the EPU 50 of the first embodiment by the fact that the intra-duct fins 231 do not have an outer periphery limiting portion. Therefore, in this embodiment, by reducing the weight of the outer duct 240 by forming the outer duct 240 from a resin material or the like, it is possible to make the weight reduction exceed the weight increase compared to the first embodiment. Therefore, in this embodiment, the weight of the EPU 50 can be reduced by the outer duct 240.

[0210] Furthermore, in this embodiment, the slits 241 are formed in the outer periphery duct 240, and therefore the weight of the outer periphery duct 240 can be reduced by the weight of the slits 241. Therefore, unlike this embodiment, the slits 241 can suppress the weight increase of the EPU 50 by the weight of the outer periphery duct 240, compared to a configuration in which the slits 241 are not formed in the outer periphery duct 240.

[0211] Eleventh Embodiment In the above-described tenth embodiment, the extending wall 243 and the slit portion 241 are located downstream of the annular wall 242 with respect to the propeller wind Wp. In contrast, in the eleventh embodiment, the annular wall 242 may be located upstream of the extending wall 243 and the slit portion 241 with respect to the propeller wind Wp. Configurations, actions, and effects not specifically described in the eleventh embodiment are the same as those in the tenth embodiment. The eleventh embodiment will be described mainly with respect to differences from the tenth embodiment.

[0212] 26 to 28 , the outer circumferential duct 240 is attached to the inverter housing 90 in the opposite direction to that of the tenth embodiment. That is, the outer circumferential duct 240 is attached to the inverter housing 90 so that the second end face 240b faces the upstream side of the propeller wind Wp. In the outer circumferential duct 240, the second end face 240b and the extending wall 243 are disposed on the inverter upstream wall 96 side in the axial direction AD, and the first end face 240a and the annular wall 242 are disposed on the inverter downstream wall 97 side. The slit portion 241 is open toward the upstream side of the propeller wind Wp.

[0213] As shown in Figures 26 and 27, the extension wall 243 is provided on the outer circumferential side of the axially parallel portion 233 and the extended parallel portion 234. The extension wall 243 is positioned offset in the circumferential direction CD from the extended parallel portion 234. For example, the extension wall 243 is provided between adjacent extended parallel portions 234 in the circumferential direction CD. A gap is formed between the extension wall 243 and the extended parallel portion 234. In the fin flow path 130, the propeller wind Wp flows outward through the gap between the extension wall 243 and the extended flight portion of the fin outer peripheral opening 133. Note that in Figure 27, the extension wall 243 is hatched with dots to clearly indicate its position.

[0214] 26 and 28 , the annular wall 242 is provided at a position aligned in the radial direction RD on at least a part of the outer circumferential parallel portion 232. The annular wall 242 spans two outer circumferential parallel portions 232 that are adjacent in the circumferential direction CD. The annular wall 242 guides the propeller wind Wp that flows through the fin flow passages 130 in the axial direction AD toward the motor housing 70 on the downstream side.

[0215] According to this embodiment, the outer periphery duct 240 is attached to the inverter housing 90 with the slit portion 241 oriented in the radial direction RD to be aligned with the extended parallel portion 234 of the outer periphery parallel portion 232 and the extended parallel portion 234. In this configuration, the propeller wind Wp flowing toward the outer periphery along the axial parallel portion 233 can flow out toward the outer periphery from the slit portion 241. In the fin flow path 130, a balanced state is achieved between the flow rate and flow velocity of the propeller wind Wp flowing out toward the outer periphery from the slit portion 241, thereby improving the heat dissipation performance of the in-duct fins 231.

[0216] <Other Embodiments> The disclosure of this specification is not limited to the exemplified embodiments. The disclosure encompasses the exemplified embodiments and modifications thereto by those skilled in the art. For example, the disclosure is not limited to the combinations of parts and elements shown in the embodiments, and can be implemented in various modifications. The disclosure can be implemented in various combinations. The disclosure can have additional parts that can be added to the embodiments. The disclosure encompasses embodiments in which parts and elements of the embodiments are omitted. The disclosure encompasses the substitution or combination of parts and elements between one embodiment and another embodiment. The disclosed technical scope is not limited to the description of the embodiments. The disclosed technical scope is defined by the claims, and should be interpreted as including all modifications within the meaning and scope equivalent to the claims.

[0217] In each of the above embodiments, the housing such as the inverter housing 90 may be provided with any number of peripheral fins such as the inverter fins 92. At least one of the multiple inverter fins 92 may be provided to correspond to a peripheral fin.

[0218] In each of the above embodiments, the outer periphery limiting portion may be provided in any manner on the outer periphery fin. For example, in the first embodiment, the outer periphery limiting portion, such as the outer periphery intersection portion 122, may be provided on either side of the outer periphery parallel portion 112 or other outer periphery fin portion in the circumferential direction CD. That is, the outer periphery limiting portion may extend toward at least one side of the outer periphery fin portion in the circumferential direction CD. Furthermore, the outer periphery limiting portion may be provided at a position spaced apart from the outer periphery end of the outer periphery fin portion toward the inner periphery. In the seventh embodiment, the expanding fin portion 201 may extend to either side in the circumferential direction CD with respect to the motor radial line Crd. That is, it is sufficient that at least one of the pair of fin expansion surfaces 201a is inclined with respect to the motor radial line Crd.

[0219] In each of the above embodiments, the fin flow paths 130 may be provided in any manner. For example, the fin flow paths 130 may not have a fin outer peripheral opening 133. For example, in the above first embodiment, a gap may not be formed between two cross fin portions 121 adjacent to each other in the circumferential direction CD. Furthermore, any size relationship may be established among the upstream opening area S131, the downstream opening area S132, and the outer peripheral opening area S133. For example, the downstream opening area S132 may be equal to or smaller than the outer peripheral opening area S133.

[0220] In each of the above embodiments, the outer circumferential fins do not have to have axial fin portions as long as they have an outer circumferential fin portion, an outer circumferential extension portion, and an outer circumferential limiting portion. For example, in the first embodiment, the inverter fin 92 does not have to have the axial parallel portion 113. Furthermore, the outer circumferential fins may have any arrangement of the outer circumferential fin portion, the outer circumferential extension portion, and the outer circumferential limiting portion. A plurality of outer circumferential fin portions, outer circumferential extension portions, and outer circumferential limiting portions may be arranged in the axial direction AD or the radial direction RD.

[0221] In each of the above embodiments, the axial fin does not have to have an outer peripheral fin portion as long as it has an axial fin portion, an axial extension portion, and an axial limiting portion. For example, in the above first embodiment, the inverter fin 92 does not have to have at least one of the outer peripheral parallel portion 112 and the outer peripheral intersection portion 122. Furthermore, the axial fin may have any arrangement of the axial fin portion, the axial extension portion, and the axial limiting portion. A plurality of axial fin portions, axial extension portions, and axial source portions may be arranged in the radial direction RD or the axial direction AD.

[0222] In each of the above embodiments, the outer peripheral component, inner peripheral component, low-profile component, and high-profile component may be provided inside the housing in any manner. For example, in the first embodiment, the switch component 175 may be provided as an inner peripheral component or a high-profile component. Furthermore, at least one of the capacitor component 176 and the filter component 177 may be provided as an outer peripheral component or a low-profile component. Furthermore, the outer peripheral component or the high-profile component may be provided in a position aligned with the outer peripheral upstream wall 96a in the axial direction AD.

[0223] In each of the above embodiments, the peripheral fins may be motor fins 72. For example, the motor device 60 may be provided upstream of the inverter device 80 with respect to the propeller wind Wp. In this configuration, the motor 61, motor stator 62, motor rotor 63, etc. correspond to the heat-generating parts, and the motor housing 70 corresponds to the housing. The motor fins 72 are provided on the motor housing 70 so as to serve as peripheral fins.

[0224] In each of the above embodiments, the motor 61 and the inverter unit 170 may be housed in a common housing. For example, the common housing is a housing in which the motor housing 70 and the inverter housing 90 are integrated. The common housing is provided with peripheral fins. In the common housing, the motor 61 and the inverter unit 170 correspond to heat-generating parts.

[0225] In each of the above embodiments, the motor 61 does not have to be a double-rotor motor. For example, the motor 61 may be a single-rotor motor having one rotor. Furthermore, the motor 61 does not have to be an axial gap motor. For example, the motor 61 may be a radial gap motor. In this motor 61, the motor stator 62 and the motor rotor 63 are aligned in the radial direction RD.

[0226] In each of the above embodiments, the airflow of the propeller wind Wp may be generated in any manner. For example, a blower such as a fan that generates an airflow flowing in the axial direction AD may be provided to the EPU 50. The blower may or may not be included in the EPU 50. Furthermore, the airflow flowing in the axial direction AD may be flight wind generated as the eVTOL 10 flies.

[0227] In each of the above embodiments, the slit portion 241 may be formed in any manner in the outer circumferential duct 240. For example, in the above tenth embodiment, the slit portion 241 may be provided at a position aligned with the duct inner fin 231 in the radial direction RD. The slit portion 241 may extend in the circumferential direction CD so as to span two fin outer circumferential openings 133 adjacent in the circumferential direction CD. The multiple slit portions 241 may include a slit portion 241 that opens toward the first end face 240a and a slit portion 241 that opens toward the second end face 240b. The slit portion 241 may not be open in the axial direction AD. For example, the slit portion 241 may be provided between the first end face 240a and the second end face 240b in the axial direction AD. In this configuration, a pair of annular walls 242 may be arranged in the axial direction AD with the slit portion 241 interposed therebetween. Furthermore, the outer circumferential duct 240 may not be provided with a slit portion 241.

[0228] In each of the above embodiments, at least a portion of the parallel fin portion 111 does not have to extend parallel to the motor radial line Crd. For example, in the parallel fin portion 111, at least one of the outer circumferential parallel portion 112, the axial parallel portion 113, and the extended parallel portion 114 may be inclined in the circumferential direction CD with respect to the motor radial line Crd. Even in this configuration, it is sufficient that the parallel fin portion 111 as a whole extends in the radial direction RD.

[0229] In each of the above embodiments, the eVTOL 10 may be configured such that at least one propeller 20 is driven by at least one EPU 50. For example, one propeller 20 may be driven by multiple EPUs 50, or multiple propellers 20 may be driven by one EPU 50.

[0230] In each of the above embodiments, the aircraft equipped with the EPU 50 does not have to be a vertical take-off and landing aircraft as long as it is electrically powered. For example, the aircraft may be an electrically powered aircraft capable of take-off and landing with a runway. Furthermore, the aircraft may be a rotary-wing aircraft or a fixed-wing aircraft. The aircraft may also be an unmanned aircraft.

[0231] In each of the above embodiments, the moving body on which the EPU 50 is mounted does not have to be an aircraft as long as it can move by rotation of a rotating body. For example, the moving body may be a vehicle, a ship, a construction machine, or an agricultural machine. For example, if the moving body is a vehicle or a construction machine, the rotating body may be a wheel for movement, and the output shaft may be an axle. If the moving body is a ship, the rotating body may be a screw propeller for propulsion, and the output shaft may be a propeller shaft.

[0232] (Disclosure of Technical Ideas) This specification discloses multiple technical ideas described in the following multiple clauses. Some clauses may be described in a multiple dependent form, with the subsequent clause alternatively referring to the preceding clause. Furthermore, some clauses may be described in a multiple dependent form, with the subsequent clause referring to another multiple dependent clause. These multiple dependent clauses define multiple technical ideas.

[0233] (Technical Idea 1) A drive device (50) driven by electricity, comprising: a heat generating portion (170) that generates heat when current is applied; a housing (90) having a housing outer peripheral surface (910) extending in an axial direction (AD) and accommodating the heat generating portion; and outer peripheral fins (92) extending from the housing outer peripheral surface toward the outer periphery, arranged in a circumferential direction (CD) of the housing, and dissipating heat from the heat generating portion to the outside of the housing, wherein the outer peripheral fins comprise: an outer peripheral fin portion (112, 122, 202) extending in the axial direction along the housing outer peripheral surface; an outer peripheral extension portion (114, 124, 204) extending from the outer peripheral fin portion in the axial direction beyond the housing outer peripheral surface; and an outer peripheral limiting portion (122, 124, 202, 204) included in at least one of the outer peripheral fin portion and the outer peripheral extension portion, which limits gas from passing between two outer peripheral fins adjacent in the circumferential direction toward the outer periphery. A drive unit having:

[0234] (Technical Concept 2) The drive device according to Technical Concept 1, wherein the outer periphery limiting portion is provided so as to open a space between two of the outer periphery fins adjacent in the circumferential direction to the outer periphery side.

[0235] (Technical Idea 3) A drive device according to Technical Idea 1 or 2, wherein between two of the outer peripheral fins adjacent in the circumferential direction, there are formed an outer peripheral opening (133) that is opened toward the outer peripheral side by the outer peripheral limiting portion, and an opposite opening (132) that is opened toward the opposite side of the outer peripheral extension portion in the axial direction, and the opening area (S133) of the outer peripheral opening is smaller than the opening area (S132) of the opposite opening.

[0236] (Technical Idea 4) A drive device described in any one of Technical Ideas 1 to 3, wherein the heat generating portion has a plurality of outer peripheral parts (175) arranged in the circumferential direction along the outer peripheral surface of the housing, and the outer peripheral fin portion is provided on the outer peripheral side of the outer peripheral parts at a position spanning the outer peripheral parts in the axial direction.

[0237] (Technical Idea 5) A drive device according to any one of Technical Ideas 1 to 4, wherein the outer periphery limiting portion extends in the axial direction across the boundary between the outer periphery fin portion and the outer periphery extension portion so as to be included in both the outer periphery fin portion and the outer periphery extension portion.

[0238] (Technical Idea 6) A drive device described in any one of Technical Ideas 1 to 5, wherein the heat generating portion has a plurality of outer peripheral parts (175) arranged in the circumferential direction along the outer peripheral surface of the housing, and the outer peripheral limiting portion is provided on the outer peripheral side of the outer peripheral parts at a position spanning the outer peripheral parts in the axial direction.

[0239] (Technical Idea 7) A drive device according to any one of Technical Ideas 1 to 6, wherein the housing has a housing cover surface (911) that extends so as to intersect with the housing outer peripheral surface and covers the heat generating portion from the axial direction, the outer peripheral fin has an axial fin portion (113, 203) that extends from the housing cover surface in the axial direction and extends toward the outer periphery along the housing cover surface, and the outer peripheral extension portion extends from the axial fin portion toward the outer periphery of the housing outer peripheral surface.

[0240] (Technical Idea 8) The heat generating portion has a plurality of outer peripheral parts (175) arranged in the circumferential direction along the outer peripheral surface of the housing, and the axial fin portion is arranged in a position that straddles the outer peripheral parts in the radial direction (RD) of the housing at a position that is aligned with the outer peripheral parts in the axial direction. This is a drive device described in Technical Idea 7.

[0241] (Technical Idea 9) A drive device according to Technical Idea 7 or 8, wherein the heat generating portion has a plurality of outer peripheral parts (175) arranged in the circumferential direction along the outer peripheral surface of the housing, and an inner peripheral part (176, 177) arranged more inward than the outer peripheral parts, and the axial fin portion is arranged in a position where it is aligned with the outer peripheral parts and the inner peripheral parts in the axial direction (RD) of the housing and straddles both the outer peripheral parts and the inner peripheral parts.

[0242] (Technical Idea 10) The housing has a housing covering surface (911) that extends in a direction intersecting the housing outer peripheral surface and covers the heat generating portion from the axial direction, and the housing covering surface has: an outer peripheral covering surface (911a) that extends in the circumferential direction along the housing outer peripheral surface; an inner peripheral covering surface (911b) that is provided inwardly of the outer peripheral covering surface at a position that protrudes further in the axial direction than the outer peripheral covering surface and extends in the circumferential direction; and an inclined covering surface (911d) that connects the outer peripheral covering surface and the inner peripheral covering surface while inclining toward the outer peripheral side; and the heat generating portion has: a low-profile part (175) that is provided on the outer peripheral covering surface at a position aligned with the axial direction, and high-profile parts (176, 177) that are taller in the axial direction than the low-profile part and are provided on the inner peripheral covering surface at a position aligned with the inner peripheral covering surface in the axial direction, A drive device described in any one of technical ideas 1 to 9, wherein the outer peripheral extension portion extends from the outer peripheral fin portion in the axial direction beyond the outer peripheral cover surface.

[0243] (Technical Idea 11) A drive device according to any one of Technical Ideas 1 to 10, wherein the outer fin has: a radial extension portion (112, 114) included in at least one of the outer fin portion and the outer extension portion and extending in the radial direction (RD) of the housing; and a circumferential extension portion (122, 124) as the outer periphery limiting portion, provided at a position spaced outward from the outer periphery surface of the housing and extending in the circumferential direction from the outer fin portion.

[0244] (Technical Idea 12) A drive device according to any one of Technical Ideas 1 to 11, wherein the outer peripheral extension portion has an extension base portion (114) extending in the radial direction (RD) of the housing, an extension intersection portion (124) which is the outer peripheral limiting portion and extends from the extension base portion in the circumferential direction, and a lightening portion (115) provided in at least a part of the extension base portion.

[0245] (Technical Idea 13) The outer peripheral fins are arranged in the circumferential direction and form a pair of fin extension surfaces (201a) in which the width of the outer peripheral fins in the circumferential direction gradually increases toward the outer periphery, and have an extension fin portion (201) extending in the axial direction along the housing outer peripheral surface, and the extension fin portion forms the outer peripheral fin portion, the outer peripheral extension portion, and the outer peripheral limiting portion, in a drive device described in any one of Technical Ideas 1 to 12.

[0246] (Technical Idea 14) The distance between two adjacent outer peripheral fins in the circumferential direction includes an outer peripheral surface distance (D3) that is the distance on the outer peripheral surface of the housing, and an open opening distance (D2) that is the distance at an outer peripheral open opening (133) that is opened toward the outer periphery by the outer peripheral limiting portion, and the ratio (Ro) of the open opening distance to the outer peripheral surface distance is within a range of 0.1 or more and 0.3 or less. A drive device described in any one of Technical Ideas 1 to 13.

[0247] (Technical Idea 15) A drive device according to any one of Technical Ideas 1 to 14, comprising an intervening fin (221) that is provided between two of the outer peripheral fins that are adjacent in the circumferential direction, extends from the outer peripheral surface of the housing toward the outer periphery, releases heat from the heat generating portion to the outside of the housing, and does not have the outer peripheral limiting portion.

[0248] (Technical Idea 16) A drive device (50) driven by electricity, comprising: a heat generating portion (170) that generates heat when current is applied; a housing (90) having a housing outer peripheral surface (910) extending in an axial direction (AD) and accommodating the heat generating portion; outer peripheral fins (231) extending from the housing outer peripheral surface toward the outer periphery, arranged in a circumferential direction (CD) of the housing, and dissipating heat from the heat generating portion to the outside of the housing; and an outer peripheral duct (240) provided on the outer periphery of the housing outer peripheral surface via the outer peripheral fins so as to cover the housing outer peripheral surface from the outer periphery, wherein the outer peripheral fin has an outer peripheral fin portion (232) extending in the axial direction along the housing outer peripheral surface, and an outer peripheral extension portion (234) extending from the outer peripheral fin portion in the axial direction beyond the housing outer peripheral surface, and the outer peripheral duct A drive device having a duct restricting portion (242, 243) that restricts the flow of gas passing between two of the outer circumferential fins adjacent to each other in the circumferential direction toward the outer circumferential side, and that extends in the axial direction so as to span between the outer circumferential fin portion and the outer circumferential extension portion.

[0249] (Technical Idea 17) A ventilation section (241) is formed in the outer circumferential duct to allow ventilation through the outer circumferential duct, and the duct restriction section is arranged so that the space between two outer circumferential fins adjacent in the circumferential direction is open to the outer circumferential side through the ventilation section, which is a drive device described in Technical Idea 16.

[0250] (Technical Concept 18) The drive device according to Technical Concept 17, wherein the outer circumferential duct is provided such that the ventilation portion is aligned with the outer circumferential fin of the outer circumferential fin and the outer circumferential extension portion in the radial direction (RD).

[0251] (Technical Concept 19) The drive device according to Technical Concept 17, wherein the outer circumferential duct is provided such that the ventilation portion is aligned in the radial direction (RD) with the outer circumferential extension portion out of the outer circumferential fin and the outer circumferential extension portion.

[0252] (Technical Idea 20) A drive device (50) driven by electricity, comprising: a heat generating portion (170) that generates heat when current is applied; a housing (90) that houses the heat generating portion, the housing (90) having a housing outer peripheral surface (910) extending in an axial direction (AD) and a housing cover surface (911) that extends so as to intersect with the housing outer peripheral surface and covers the heat generating portion from the axial direction; and axial fins (92) that extend in the axial direction from the housing cover surface, are arranged in a circumferential direction (CD) of the housing, and release heat from the heat generating portion to the outside of the housing, the axial fins comprising: axial fin portions (113, 203) that extend radially outward along the housing cover surface; and axial extension portions (114, 124, 204) that extend radially outward from the axial fin portion further radially outward than the housing outer peripheral surface. a shaft limiting portion (124, 204) included in the shaft extension portion and limiting the flow of gas passing between two circumferentially adjacent shaft fins toward the outer periphery.

[0253] (Technical Idea 21) A drive device (50) driven by electricity, comprising: a heat generating portion (170) that generates heat when current is applied; a housing (90) that houses the heat generating portion, the housing having a housing outer peripheral surface (910) extending in an axial direction (AD) and a housing cover surface (911) that extends so as to intersect with the housing outer peripheral surface and covers the heat generating portion from the axial direction; axial fins (92) that extend in the axial direction from the housing cover surface, are arranged in a circumferential direction (CD) of the housing, and release heat from the heat generating portion to the outside of the housing; and an outer peripheral duct (240) that is provided on the housing outer peripheral surface and on the outer peripheral side of the housing outer peripheral surface and covers the housing outer peripheral surface and the axial fins from the outer peripheral side, wherein the axial fins have a axial fin portion (232) that extends toward the outer peripheral side along the housing cover surface, and a axial extension portion (234) that extends from the axial fin portion to the outer peripheral side of the housing outer peripheral surface, The outer duct has a duct restricting portion (242, 243) that restricts the flow of gas passing between two circumferentially adjacent axial fins toward the outer periphery, and extends in the axial direction so as to span between the axial fin portion and the axial extension portion.

[0254] (Technical Idea 22) A drive device according to any one of Technical Ideas 1 to 21, comprising: a motor (61) to which electric power is supplied; and an inverter unit (170) that converts the electric power supplied to the motor, wherein the axial direction is the direction in which the rotation axis (Cm) of the motor extends; and at least one of the motor and the inverter unit is housed in the housing as the heat generating unit.

[0255] (Technical Concept 23) The drive device according to any one of Technical Concepts 1 to 22, which is a rotating electric machine provided in an aircraft (10) and drives the aircraft to fly.

Claims

1. A drive device (50) driven by electricity, comprising: a heat generating portion (170) that generates heat when current is applied; a housing (90) having a housing outer peripheral surface (910) extending in an axial direction (AD) and accommodating the heat generating portion; and outer peripheral fins (92) extending from the housing outer peripheral surface toward the outer periphery, arranged in a circumferential direction (CD) of the housing, and dissipating heat from the heat generating portion to the outside of the housing, wherein the outer peripheral fins have: an outer peripheral fin portion (112, 122, 202) extending in the axial direction along the housing outer peripheral surface; an outer peripheral extension portion (114, 124, 204) extending from the outer peripheral fin portion in the axial direction beyond the housing outer peripheral surface; and an outer peripheral limiting portion (122, 124, 202, 204) included in at least one of the outer peripheral fin portion and the outer peripheral extension portion and limiting the flow of gas passing between two outer peripheral fins adjacent to each other in the circumferential direction toward the outer periphery.

2. The drive unit according to claim 1, wherein the outer peripheral limiting portion is provided so as to open the space between two of the outer peripheral fins adjacent in the circumferential direction to the outer peripheral side.

3. A drive unit as described in claim 1 or 2, wherein between two of the outer peripheral fins adjacent in the circumferential direction, there is formed an outer peripheral opening (133) that is opened toward the outer periphery by the outer peripheral limiting portion, and an opposite opening (132) that is opened toward the opposite side to the outer peripheral extension portion in the axial direction, and the opening area (S133) of the outer peripheral opening is smaller than the opening area (S132) of the opposite opening.

4. A drive device as described in claim 1 or 2, wherein the heat generating portion has a plurality of outer peripheral parts (175) arranged in the circumferential direction along the outer peripheral surface of the housing, and the outer peripheral fin portion is provided on the outer peripheral side of the outer peripheral parts at a position spanning the outer peripheral parts in the axial direction.

5. A drive unit as described in claim 1 or 2, wherein the outer peripheral limiting portion extends in the axial direction across the boundary between the outer peripheral fin portion and the outer peripheral extension portion so as to be included in both the outer peripheral fin portion and the outer peripheral extension portion.

6. A drive device as described in claim 1 or 2, wherein the heat generating portion has a plurality of outer peripheral parts (175) arranged in the circumferential direction along the outer peripheral surface of the housing, and the outer peripheral limiting portion is provided on the outer peripheral side of the outer peripheral parts at a position spanning the outer peripheral parts in the axial direction.

7. A drive unit as described in claim 1 or 2, wherein the housing has a housing cover surface (911) that extends so as to intersect with the housing outer peripheral surface and covers the heat generating portion from the axial direction, the outer peripheral fin has an axial fin portion (113, 203) that extends from the housing cover surface in the axial direction and extends toward the outer periphery along the housing cover surface, and the outer peripheral extension portion extends from the axial fin portion toward the outer periphery of the housing outer peripheral surface.

8. A drive unit as described in claim 7, wherein the heat generating portion has a plurality of outer peripheral parts (175) arranged in the circumferential direction along the outer peripheral surface of the housing, and the axial fin portion is provided in a position that straddles the outer peripheral parts in the radial direction (RD) of the housing at a position that is aligned in the axial direction on the outer peripheral parts.

9. A drive unit as described in claim 7, wherein the heat generating portion has a plurality of outer peripheral parts (175) arranged in the circumferential direction along the outer peripheral surface of the housing, and an inner peripheral part (176, 177) arranged more inwardly than the outer peripheral parts, and the axial fin portion is arranged at a position straddling both the outer peripheral part and the inner peripheral part in the radial direction (RD) of the housing, at a position aligned with the outer peripheral part and the inner peripheral part in the axial direction.

10. The drive device described in claim 1 or 2, wherein the housing has a housing covering surface (911) extending in the circumferential direction along the housing outer peripheral surface and covering the heat generating portion from the axial direction, the housing covering surface having: an outer peripheral covering surface (911a) extending in the circumferential direction along the housing outer peripheral surface; an inner peripheral covering surface (911b) provided on the inner side of the outer peripheral covering surface at a position protruding in the axial direction from the outer peripheral covering surface and extending in the circumferential direction; and an inclined covering surface (911d) connecting the outer peripheral covering surface and the inner peripheral covering surface while inclining toward the outer peripheral side; the heat generating portion has: a low-profile part (175) provided in a position aligned with the outer peripheral covering surface in the axial direction; and high-profile parts (176, 177) that are taller in the axial direction than the low-profile part and are provided in a position aligned with the inner peripheral covering surface in the axial direction; and the outer peripheral extension portion extends in the axial direction from the outer peripheral fin portion beyond the outer peripheral covering surface.

11. A drive device as described in claim 1 or 2, wherein the outer peripheral fin has: a radial extension portion (112, 114) included in at least one of the outer peripheral fin portion and the outer peripheral extension portion and extending in the radial direction (RD) of the housing; and a circumferential extension portion (122, 124) as the outer peripheral limiting portion, which is provided at a position away from the outer peripheral surface of the housing toward the outer periphery and extends in the circumferential direction from the outer peripheral fin portion.

12. A drive device as described in claim 1 or 2, wherein the outer peripheral extension portion has an extension base portion (114) extending in the radial direction (RD) of the housing, an extension intersection portion (124) which is the outer peripheral limiting portion and extends in the circumferential direction from the extension base portion, and a hollowed-out portion (115) provided in at least a portion of the extension base portion.

13. A drive unit as described in claim 1 or 2, wherein the outer peripheral fins form a pair of fin extension surfaces (201a) arranged in the circumferential direction and the width of the outer peripheral fins in the circumferential direction gradually increases toward the outer peripheral side, and have an extension fin portion (201) extending in the axial direction along the housing outer peripheral surface, and the extension fin portion forms the outer peripheral fin portion, the outer peripheral extension portion and the outer peripheral limiting portion.

14. A drive unit as described in claim 1 or 2, wherein the distance between two adjacent outer peripheral fins in the circumferential direction includes an outer peripheral surface distance (D3) which is the distance on the outer peripheral surface of the housing, and an open port distance (D2) which is the distance at an outer peripheral open port (133) opened toward the outer periphery by the outer peripheral limiting portion, and the ratio (Ro) of the open port distance to the outer peripheral surface distance is within the range of 0.1 or more and 0.3 or less.

15. A drive unit as described in claim 1 or 2, further comprising an intervening fin (221) provided between two of the outer peripheral fins adjacent to each other in the circumferential direction, extending from the outer peripheral surface of the housing toward the outer periphery, dissipating heat from the heat generating portion to the outside of the housing, and not having an outer peripheral limiting portion.

16. A drive device (50) driven by electricity, comprising: a heat generating section (170) that generates heat when current is applied; a housing (90) having a housing outer peripheral surface (910) extending in an axial direction (AD) and accommodating the heat generating section; outer peripheral fins (231) extending from the housing outer peripheral surface toward the outer peripheral side, arranged in a circumferential direction (CD) of the housing, and dissipating heat from the heat generating section to the outside of the housing; and an outer peripheral duct (240) provided on the outer peripheral side of the housing outer peripheral surface via the outer peripheral fins so as to cover the housing outer peripheral surface from the outer peripheral side, wherein the outer peripheral fin has an outer peripheral fin section (232) extending in the axial direction along the housing outer peripheral surface, and an outer peripheral extension section (234) extending from the outer peripheral fin section in the axial direction beyond the housing outer peripheral surface, and the outer peripheral duct is A drive unit having a duct restriction portion (242, 243) that restricts the flow of gas passing between two of the outer circumferential fins adjacent to each other in the circumferential direction toward the outer circumferential side, and extending in the axial direction so as to span the outer circumferential fin portion and the outer circumferential extension portion.

17. A drive unit as described in claim 16, wherein the outer circumferential duct is formed with a ventilation portion (241) penetrating the outer circumferential duct in a radial direction (RD) to allow ventilation through the outer circumferential duct, and the duct restriction portion is arranged so that the space between two outer circumferential fins adjacent to each other in the circumferential direction is opened to the outer circumferential side through the ventilation portion.

18. The drive unit according to claim 17, wherein said outer circumferential duct is provided such that said vent portion is aligned in a radial direction (RD) with said outer circumferential fin and one of said outer circumferential extensions.

19. The drive unit according to claim 17, wherein said outer circumferential duct is provided such that said vent is aligned in a radial direction (RD) with one of said outer circumferential fins and said outer circumferential extension.

20. A drive device (50) driven by electricity, comprising: a heat generating portion (170) that generates heat when current is applied; a housing (90) that contains the heat generating portion, the housing having a housing outer peripheral surface (910) extending in an axial direction (AD) and a housing cover surface (911) that extends so as to intersect with the housing outer peripheral surface and covers the heat generating portion from the axial direction; and shaft fins (92) that extend in the axial direction from the housing cover surface, are arranged in a circumferential direction (CD) of the housing, and release heat from the heat generating portion to the outside of the housing, the shaft fins comprising: a shaft fin portion (113, 203) that extends toward the outer periphery along the housing cover surface; and a shaft extension portion (114, 124, 204) that extends from the shaft fin portion toward the outer periphery of the housing outer peripheral surface. a shaft limiting portion (124, 204) included in the shaft extension portion and limiting the flow of gas passing between two of the circumferentially adjacent shaft fins toward the outer periphery.

21. A drive device (50) driven by electricity, comprising: a heat generating portion (170) which generates heat when current is applied; a housing (90) which contains the heat generating portion and has a housing outer peripheral surface (910) extending in an axial direction (AD) and a housing cover surface (911) which extends so as to intersect with the housing outer peripheral surface and covers the heat generating portion from the axial direction; axial fins (92) which extend in the axial direction from the housing cover surface and are arranged in a circumferential direction (CD) of the housing and release heat from the heat generating portion to the outside of the housing; and an outer peripheral duct (240) which is provided on the outer peripheral side of the housing outer peripheral surface and the axial fins so as to cover the housing outer peripheral surface and the axial fins from the outer peripheral side, wherein the axial fin has: a axial fin portion (232) which extends toward the outer peripheral side along the housing cover surface; and a axial extension portion (234) which extends from the axial fin portion to the outer peripheral side of the housing outer peripheral surface, and the outer peripheral duct is A drive unit having a duct restriction portion (242, 243) that restricts the flow of gas passing between two circumferentially adjacent axial fins toward the outer periphery, and that extends in the axial direction so as to span between the axial fin portion and the axial extension portion.

22. A drive device as described in any one of claims 1, 16, 20 and 21, comprising: a motor (61) to which power is supplied; and an inverter unit (170) that converts the power supplied to the motor, wherein the axial direction is the direction in which the rotation axis (Cm) of the motor extends; and at least one of the motor and the inverter unit is housed in the housing as the heat generating unit.

23. The drive device according to any one of claims 1, 16, 20 and 21, which is a rotating electric machine provided in an aircraft (10) and drives the aircraft to fly.

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