Drive device

Abstract

An inverter device (80) has an inverter housing (90) and an inverter unit (170). The inverter unit (170) is housed in the inverter housing (90). The inverter housing (90) is provided with a first fin (921) and a second fin (922). The first fin (921) and the second fin (922) are arranged in the axial direction (AD) along the inverter outer peripheral surface (910). The first fin (921) and the second fin (922) extend from positions arranged in the radial direction (RD) to the axial direction (AD) in the inverter unit (170). The first fin (921) extends from the inverter unit (170) toward the upstream side. The second fin (922) extends from the inverter unit (170) toward the downstream side.

Description

Drive unit CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is based on Patent Application No. 2023-142445 filed in Japan on September 1, 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 drive unit equipped with heat dissipation fins. In this drive unit, a plurality of heat dissipation fins are provided on the outer surface of the housing. The heat dissipation fins extend in a serpentine pattern along the outer surface of the housing. Patent Document 1 states that the serpentine shape of the heat dissipation fins promotes the generation of turbulence in the air flowing between two adjacent heat dissipation fins, thereby improving the heat dissipation capacity of the heat dissipation fins.

[0004] JP 2008-186820 A

[0005] However, in the above-mentioned Patent Document 1, the entire heat dissipation fin is serpentine, which may increase pressure loss between two adjacent heat dissipation fins. If the pressure loss increases, the amount of air flowing between the two adjacent heat dissipation fins will decrease, and there is a concern that the heat dissipation effect of the heat dissipation fins will decrease.

[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 disclosed aspect is a drive device that is driven by electricity, comprising: 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; and outer peripheral fins that extend in the axial direction along the housing outer peripheral surface and are arranged in a plurality of circumferential directions of the housing along the housing outer peripheral surface, and that release heat from the heat-generating portion to the outside of the housing, wherein the housing outer peripheral surface has a first surface end and a second surface end as a pair of ends arranged in the axial direction, and the plurality of outer peripheral fins include a first outer peripheral fin that extends from a position aligned radially with the heat-generating portion of the housing toward the first surface end of the first surface end or the second surface end, and a second outer peripheral fin that is located at a position away from the first outer peripheral fin in a direction perpendicular to the radial direction and extends from a position aligned radially with the heat-generating portion toward the second surface end of the first surface end or the second surface end.

[0009] According to the above aspect, the first and second outer fins are positioned at intervals perpendicular to the axial direction. In this configuration, turbulence, such as vortices, is likely to occur in the gas, such as air, flowing through the space between the first and second outer fins at positions radially aligned with the heat-generating portion. This gas turbulence can enhance the heat dissipation effect of heat from the heat-generating portion dissipated through the first and second outer fins and the outer surface of the housing. In this way, localized gas turbulence occurring at positions radially aligned with the heat-generating portion on the outside of the housing can prevent an increase in pressure loss throughout the entire space between two circumferentially adjacent outer fins. This prevents a shortage of gas flowing between two circumferentially adjacent outer fins, while enhancing the heat dissipation effect of the gas from the heat-generating portion. As described above, the outer fins can enhance the heat dissipation effect of the housing in the drive unit.

[0010] 16. A diagram showing the configuration of an eVTOL in the 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 taken along line V-V in FIG. 3. A cross-sectional view taken along line VI-VI in FIG. 4, which is also a longitudinal cross-sectional view of the inverter device. An enlarged side view of a switch component in the inverter device. A diagram for explaining a thermal boundary layer. An enlarged side view of the periphery of a motor radial line in the inverter device. An enlarged side view of a switch component in the inverter device in Comparative Example 2. An enlarged side view of the periphery of the switch component in the inverter device in Comparative Example 2. An enlarged side view of the periphery of a motor radial line in the inverter device in the second embodiment. An enlarged side view of the periphery of a motor radial line in the inverter device in the third embodiment. A plan view of an inverter device in the fourth embodiment. A cross-sectional view taken along line XV-XV in FIG. 16. A cross-sectional view taken along line XVI-XVI in FIG. 14. A cross-sectional view taken along line XVII-XVII in FIG. 16.

[0011] 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.

[0012] 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.

[0013] 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.

[0014] 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.

[0015] 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.

[0016] 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.

[0017] 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.

[0018] 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.

[0019] 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.

[0020] 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.

[0021] 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.

[0022] 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.

[0023] 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.

[0024] 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.

[0025] 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.

[0026] 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.

[0027] 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.

[0028] 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.

[0029] 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.

[0030] 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.

[0031] 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.

[0032] 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.

[0033] 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.

[0034] 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.

[0035] 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.

[0036] 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.

[0037] 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.

[0038] 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.

[0039] 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.

[0040] 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.

[0041] 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.

[0042] 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.

[0043] 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.

[0044] 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.

[0045] 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.

[0046] 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 peripheral side of the motor outer peripheral surface 710.

[0047] 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.

[0048] 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 are formed in a plate shape and extend in a direction perpendicular to the circumferential direction CD. 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 the motor fins 72 are arranged in the circumferential direction CD along the motor outer peripheral surface 710. Furthermore, a plurality of the motor fins 72 are arranged in the axial direction AD along the motor outer peripheral surface 710.

[0049] As shown in FIGS. 3 and 6 , the inverter housing 90 includes an inverter housing main body 91 and inverter fins 92. The inverter housing main body 91 and the inverter fins 92 are formed of 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, an inverter downstream surface 912, and an inverter inner peripheral surface 913. The inverter outer peripheral surface 910 and the inverter inner peripheral surface 913 are formed in an annular shape and extend in the axial direction AD. The inverter housing 90 corresponds to a housing. The inverter outer peripheral surface 910 corresponds to the housing outer peripheral surface. The inverter inner peripheral surface 913 corresponds to the housing inner peripheral surface. Note that the motor housing 70 and the like are not shown in FIG. 6 .

[0050] The inverter outer peripheral surface 910 has an outer peripheral upstream end 910a and an outer peripheral downstream end 910b as a pair of end portions aligned in the axial direction AD. The outer peripheral upstream end 910a is the end of the pair of end portions on the inverter outer peripheral surface 910 that is closer to the inverter upstream surface 911. The outer peripheral upstream end 910a extends in the circumferential direction CD along the outer peripheral edge of the inverter upstream surface 911. The outer peripheral upstream end 910a corresponds to a first surface end portion. The outer peripheral downstream end 910b is the end of the pair of end portions on the inverter outer peripheral surface 910 that is closer to the inverter downstream surface 912. The outer peripheral downstream end 910b extends in the circumferential direction CD along the outer peripheral edge of the inverter downstream surface 912. The outer peripheral downstream end 910b corresponds to a second surface end portion.

[0051] 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.

[0052] 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.

[0053] 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 and an inverter inner peripheral surface 913. The inverter outer peripheral surface 910 is the outer peripheral surface of the inverter outer peripheral wall 95. The inverter inner peripheral surface 913 is the inner 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.

[0054] 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.

[0055] 5 and 6 , the inverter unit 170 includes the inverter circuit 81, smoothing capacitor 145, filter circuit 150, and control circuit 160. 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 greater than the distance between the inverter board 171 and the inner peripheral upstream wall 96 b.

[0056] 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. Note that the capacitor component 176, the filter component 177, and the like are not shown in FIG. 6 .

[0057] 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.

[0058] A plurality of switch components 175 are arranged in the circumferential direction CD along the inverter inner circumferential surface 913. The switch components 175 are provided on the inverter inner circumferential surface 913. The switch components 175 correspond to surface-mounted components. The switch components 175 are fixed to at least one of the inverter board 171 and the inverter inner circumferential surface 913. The switch components 175 are provided on the inverter inner circumferential surface 913 in a state in which heat is transferred from the switch components 175 to the inverter outer circumferential wall 95. For example, the switch components 175 are fixed to the inverter outer circumferential wall 95 with a fastener such as a screw in contact with the inverter inner circumferential surface 913. The switch components 175 may be provided on the inverter inner circumferential surface 913 via a heat-transfer gel or a fixing member.

[0059] The switch component 175 is disposed between the outer circumferential upstream end 910a and the outer circumferential downstream end 910b in the axial direction AD. The switch component 175 is disposed at a position away from both the inverter upstream wall 96 and the inverter downstream wall 97. The switch component 175 is disposed at a position where the outer circumferential center line Crd passes. For example, the outer circumferential center line Crd passes through the center of the switch component 175. The outer circumferential center line Crd is a center line passing through the center of the inverter outer circumferential surface 910 in the axial direction AD. The outer circumferential center line Crd passes through the middle between the outer circumferential upstream end 910a and the outer circumferential downstream end 910b. The outer circumferential center line Crd is a virtual line extending linearly. The outer circumferential center line Crd is perpendicular to the motor axis line Cm.

[0060] The capacitor component 176 and the filter component 177 are provided on the inner circumferential side of the switch component 175. For example, the capacitor component 176 and the filter component 177 are provided at a position spaced apart from the switch component 175 on the inner circumferential side. The capacitor component 176 and the filter component 177 correspond to inner circumferential components. The capacitor component 176 and the filter component 177 are provided at a position spaced apart from the motor shaft 64 on the outer circumferential side.

[0061] 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.

[0062] 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.

[0063] 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 are formed in a plate shape and extend in a direction perpendicular to the circumferential direction CD. The inverter fins 92 are provided on the inverter outer peripheral surface 910. The inverter fins 92 extend from the inverter outer peripheral surface 910 toward the outer periphery. The inverter fins 92 extend in the axial direction AD along the inverter outer peripheral surface 910. A plurality of the inverter fins 92 are arranged in the circumferential direction CD along the inverter outer peripheral surface 910 (see FIGS. 4 and 5 ). A plurality of the inverter fins 92 are also arranged in the axial direction AD along the inverter outer peripheral surface 910. The inverter fins 92 correspond to outer peripheral fins.

[0064] The multiple inverter fins 92 include first fins 921 and second fins 922. The first fins 921 and the second fins 922 are included in the inverter housing 90. The first fins 921 and the second fins 922 are aligned in the axial direction AD along the inverter outer peripheral surface 910. The first fins 921 and the second fins 922 are spaced apart in a direction perpendicular to the radial direction RD. For example, the first fins 921 and the second fins 922 are spaced apart in the axial direction AD. Multiple first fins 921 and multiple second fins 922 are aligned in the circumferential direction CD along the inverter outer peripheral surface 910.

[0065] The first fin 921 is provided closer to the outer circumferential upstream end 910a than the second fin 922. The first fin 921 is provided between the second fin 922 and the outer circumferential upstream end 910a in the axial direction AD. The first fin 921 is provided closer to the outer circumferential upstream end 910a than the outer circumferential center line Crd. The first fin 921 is sometimes referred to as an upstream fin.

[0066] The second fin 922 is provided between the first fin 921 and the outer circumferential downstream end 910b in the axial direction AD. The second fin 922 is provided closer to the outer circumferential downstream end 910b than the outer circumferential center line Crd. With respect to the propeller wind Wp, the first fin 921 is located upstream of the second fin 922. The second fin 922 is sometimes referred to as a downstream fin.

[0067] As shown in Fig. 7, the first fin 921 has a pair of first fin surfaces 111. The first fin surfaces 111 are plate surfaces of the first fin 921. The first fin surfaces 111 extend in a direction perpendicular to the circumferential direction CD. The pair of first fin surfaces 111 are aligned in the circumferential direction CD. The first fin surfaces 111 are also side surfaces of the first fin 921 and may be referred to as fin side surfaces.

[0068] The first fin 921 has a first upstream end 112 and a first downstream end 113 as a pair of ends aligned in the axial direction AD. The first upstream end 112 is the upstream end of the first fin 921. The first upstream end 112 is the end of the pair of ends of the first fin 921 that is closer to the outer peripheral upstream end 910a. The first upstream end 112 has an end face that extends in a direction perpendicular to the axial direction AD. The end face of the first upstream end 112 faces toward the outer peripheral upstream end 910a. The first downstream end 113 is the downstream end of the first fin 921. The first downstream end 113 is the end of the pair of ends of the first fin 921 that is closer to the outer peripheral downstream end 910b. The first downstream end 113 has an end face that extends in a direction perpendicular to the axial direction AD. The end face of the first downstream end 113 faces toward the outer peripheral downstream end 910b.

[0069] The first fin 921 has a shape in which the width in the circumferential direction CD gradually increases from the first upstream end 112 to the first downstream end 113. The first fin 921 corresponds to an expanding fin. The first fin 921 continuously increases toward the first downstream end 113. The width dimension W1 of the first fin 921 gradually increases toward the first downstream end 113. The width dimension W1 corresponds to the width. The width dimension W1 is the width of the first fin 921 in the circumferential direction CD. In the first fin 921, the portion where the width dimension W1 is smallest is the first upstream end 112. In the first fin 921, the portion where the width dimension W1 is largest is the first downstream end 113. The width dimension W1b of the first downstream end 113 is larger than the width dimension W1a of the first upstream end 112.

[0070] In the first fin 921, one of the pair of first fin surfaces 111 is inclined relative to the other. At least one of the pair of first fin surfaces 111 is inclined in the circumferential direction CD with respect to the motor axis Cm. For example, one of the pair of first fin surfaces 111 is inclined to one side in the circumferential direction CD with respect to the motor axis Cm. The other of the pair of first fin surfaces 111 is inclined to the other side in the circumferential direction CD with respect to the motor axis Cm. The first fin 921 is formed in a tapered shape. The first fin surface 111 extends straight in the axial direction AD. The first fin surface 111 is a tapered surface.

[0071] The first fin 921 may be expanded in stages toward the first downstream end 113. For example, the first fin surface 111 may be a stepped surface. The first fin surface 111 may be curved so as to be recessed or bulged in the circumferential direction CD. For example, the first fin surface 111 may be a curved or bent surface.

[0072] At least a portion of the first fin 921 is provided at a position aligned with the inverter unit 170 in the radial direction RD. The first downstream end 113 of the first fin 921 is provided at a position aligned with the inverter unit 170 in the radial direction RD. The first fin 921 extends from the inverter unit 170 toward only the outer circumferential upstream end 910a out of the outer circumferential upstream end 910a and the outer circumferential downstream end 910b. The first fin 921 corresponds to the first outer circumferential fin.

[0073] For example, at least a portion of the first fin 921 is provided at a position aligned in the radial direction RD with the switch component 175. The first fin 921 has a first downstream end 113 aligned in the radial direction RD with the switch component 175. The first fin 921 extends from the outer circumferential upstream end 910 a and the outer circumferential downstream end 910 b only toward the outer circumferential upstream end 910 a.

[0074] For two first fins 921 adjacent to each other in the circumferential direction CD, the first distance D1 gradually decreases from the first upstream end 112 to the first downstream end 113. The first distance D1 is the distance between two first fins 921 adjacent to each other in the circumferential direction CD. The first distance D1 continuously decreases from the first upstream end 112 to the first downstream end 113. The first distance D1 includes an upstream end distance D1a and a downstream end distance D1b. The upstream end distance D1a is the distance between the two first upstream ends 112 adjacent to each other in the circumferential direction CD. The downstream end distance D1b is the distance between the first downstream ends 113 adjacent to each other in the circumferential direction CD. The downstream end distance D1b is smaller than the upstream end distance D1a. For the first fin 921, the width dimension W1 gradually increases from the first upstream end 112 to the first downstream end 113, and therefore the first spacing D1 gradually decreases from the first upstream end 112 to the first downstream end 113.

[0075] The second fin 922 has a pair of second fin surfaces 121. The second fin surfaces 121 are plate surfaces of the second fin 922. The second fin surfaces 121 extend in a direction perpendicular to the circumferential direction CD. The pair of second fin surfaces 121 are aligned in the circumferential direction CD. The second fin surfaces 121 are also side surfaces of the second fin 922 and may be referred to as fin side surfaces.

[0076] The second fin 922 has a second upstream end 122 and a second downstream end 123 as a pair of ends aligned in the axial direction AD. The second upstream end 122 is the upstream end of the second fin 922. The second upstream end 122 is the end of the pair of ends of the second fin 922 that is closer to the outer peripheral upstream end 910a. The second upstream end 122 has an end face extending in a direction perpendicular to the axial direction AD. The end face of the second upstream end 122 faces toward the outer peripheral upstream end 910a. The second downstream end 123 is the downstream end of the second fin 922. The second downstream end 123 is the end of the pair of ends of the second fin 922 that is closer to the outer peripheral downstream end 910b. The second downstream end 123 has an end face extending in a direction perpendicular to the axial direction AD. The end face of the second downstream end 123 faces toward the outer peripheral downstream end 910b.

[0077] The second fin 922 has a shape that gradually shrinks in the circumferential direction CD from the second upstream end 122 toward the second downstream end 123. The second fin 922 is sometimes referred to as a shrinking fin. The second fin 922 continuously shrinks toward the second downstream end 123. The width dimension W2 of the second fin 922 gradually decreases toward the second downstream end 123. The width dimension W2 is the width of the second fin 922 in the circumferential direction CD. The second upstream end 122 is the portion of the second fin 922 where the width dimension W2 is largest. The second downstream end 123 is the portion of the second fin 922 where the width dimension W2 is smallest. The width dimension W2b of the second downstream end 123 is smaller than the width dimension W2a of the second upstream end 122.

[0078] In the second fin 922, one of the pair of second fin surfaces 121 is inclined relative to the other. At least one of the pair of second fin surfaces 121 is inclined in the circumferential direction CD with respect to the motor axis Cm. For example, one of the pair of second fin surfaces 121 is inclined to one side in the circumferential direction CD with respect to the motor axis Cm. The other of the pair of second fin surfaces 121 is inclined to the other side in the circumferential direction CD with respect to the motor axis Cm. The second fin 922 is formed in a tapered shape. The second fin surface 121 extends straight in the axial direction AD. The second fin surface 121 is a tapered surface.

[0079] The second fin 922 may be expanded in stages toward the second downstream end 123. For example, the second fin surface 121 may be a stepped surface. The second fin surface 121 may be curved so as to be recessed or bulged in the circumferential direction CD. For example, the second fin surface 121 may be a curved or bent surface.

[0080] At least a portion of the second fin 922 is provided at a position aligned with the switch component 175 in the radial direction RD. The second fin 922 has a second upstream end 122 aligned with the switch component 175 in the radial direction RD. The second fin 922 extends from the first upstream end 112 toward only the outer circumferential downstream end 910b out of the outer circumferential upstream end 910a and the outer circumferential downstream end 910b. The second fin 922 corresponds to a second outer circumferential fin.

[0081] For two second fins 922 adjacent in the circumferential direction CD, the second distance D2 gradually increases from the second upstream end 122 toward the second downstream end 123. The second distance D2 is the distance between two second fins 922 adjacent in the circumferential direction CD. The second distance D2 continuously decreases from the second upstream end 122 toward the second downstream end 123. The second distance D2 includes an upstream end distance D2a and a downstream end distance D2b. The upstream end distance D2a is the distance between two second upstream ends 122 adjacent in the circumferential direction CD. The downstream end distance D2b is the distance between two second downstream ends 123 adjacent in the circumferential direction CD. The downstream end distance D2b is larger than the upstream end distance D2a. For the second fin 922, the width dimension W2 gradually increases from the second upstream end 122 to the second downstream end 123, and therefore the second spacing D2 gradually decreases from the second upstream end 122 to the second downstream end 123.

[0082] The first downstream end 113 and the second upstream end 122 of the first fin 921 and the second fin 922 face each other. The first downstream end 113 and the second upstream end 122 are aligned in the axial direction AD. The first downstream end 113 and the second upstream end 122 are not misaligned in the circumferential direction CD. For example, one of the first downstream end 113 and the second upstream end 122 does not protrude further in the circumferential direction CD than the other. Furthermore, the width dimension W1b of the first downstream end 113 and the width dimension W2a of the second upstream end 122 are the same.

[0083] The third distance D3 is larger than the downstream end distance D1b and the upstream end distance D2a. Moreover, the third distance D3 is smaller than the upstream end distance D1a and the downstream end distance D2b. The third distance D3 is the distance between the first fin 921 and the second fin 922 in the axial direction AD. Note that the third distance D3 may be smaller than or the same as the downstream end distance D1b and the upstream end distance D2a. Moreover, the third distance D3 may be larger than or the same as the upstream end distance D1a and the downstream end distance D2b.

[0084] In the inverter housing 90, fin flow paths 130 are formed by the multiple inverter fins 92. The fin flow paths 130 extend along the inverter outer peripheral surface 910 in a direction perpendicular to the radial direction RD. The fin flow paths 130 extend in the axial direction AD and the circumferential direction CD along the outer surfaces of the inverter fins 92. The fin flow paths 130 are open toward the upstream side, downstream side, and outer peripheral side. For example, the fin flow paths 130 are open in the axial direction AD toward the outer peripheral upstream end 910a and the outer peripheral downstream end 910b. The fin flow paths 130 are also open toward the side opposite the inverter outer peripheral surface 910.

[0085] The fin flow path 130 has a first flow path 131, a second flow path 132, and a connecting flow path 133. The first flow path 131, the second flow path 132, and the connecting flow path 133 are aligned along the inverter outer peripheral surface 910. The first flow path 131 and the second flow path 132 are aligned in the axial direction AD. The first flow path 131 is located closer to the outer peripheral upstream end 910a than the second flow path 132. The connecting flow path 133 is provided between the first flow path 131 and the second flow path 132 in the axial direction AD. The connecting flow path 133 connects the first flow path 131 and the second flow path 132.

[0086] The first flow passage 131 is a space between two adjacent first fins 921 in the circumferential direction CD. The first flow passage 131 is formed by two first fin surfaces 111 that face each other in the circumferential direction CD. The first flow passage 131 extends in the axial direction AD along the inverter outer peripheral surface 910 and the first fin surfaces 111.

[0087] The first flow passage 131 is open toward the upstream side, downstream side, and outer periphery. The first flow passage 131 has a first upstream port 131a and a first downstream port 131b. The first upstream port 131a opens the first flow passage 131 toward the upstream side. The first upstream port 131a is located at a position aligned with the first upstream end 112 in the circumferential direction CD. The first downstream port 131b opens the first flow passage 131 toward the downstream side. The first downstream port 131b is located at a position aligned with the first downstream end 113 in the circumferential direction CD. The first upstream port 131a and the first downstream port 131b are aligned with each other in the axial direction AD.

[0088] In the circumferential direction CD, the width dimension of the first flow passage 131 is the same as the first interval D1. The width dimension of the first flow passage 131 is maximum at the first upstream port 131a. The width dimension of the first upstream port 131a is the same as the interval D1a. The width dimension of the first flow passage 131 is minimum at the first downstream port 131b. The width dimension of the first downstream port 131b is the same as the interval D1b.

[0089] The cross-sectional area of ​​the first flow path 131 gradually decreases from the first upstream port 131a toward the first downstream port 131b. The cross-sectional area of ​​the first flow path 131 is the area of ​​the first flow path 131 on a plane obtained by cutting the first flow path 131 in a direction perpendicular to the axial direction AD. In the first flow path 131, the first upstream port area S131a is the largest. The first upstream port area S131a is the open area of ​​the first upstream port 131a. The first upstream port area S131a is sometimes referred to as the cross-sectional area of ​​the first upstream port 131a. In the first flow path 131, the first downstream port area S131b is the smallest. The first downstream port area S131b is the open area of ​​the first downstream port 131b. The first downstream port area S131b is sometimes referred to as the cross-sectional area of ​​the first downstream port 131b.

[0090] The second flow passage 132 is a space between two adjacent second fins 922 in the circumferential direction CD. The second flow passage 132 is formed by two second fin surfaces 121 that face each other in the circumferential direction CD. The second flow passage 132 extends in the axial direction AD along the inverter outer peripheral surface 910 and the second fin surfaces 121.

[0091] The second flow passage 132 is open toward the upstream side, downstream side, and outer periphery side. The second flow passage 132 has a second upstream port 132a and a second downstream port 132b. The second upstream port 132a opens the second flow passage 132 toward the upstream side. The second upstream port 132a is located at a position aligned with the second upstream end 122 in the circumferential direction CD. The second downstream port 132b opens the second flow passage 132 toward the downstream side. The second downstream port 132b is located at a position aligned with the second downstream end 123 in the circumferential direction CD. The second upstream port 132a and the second downstream port 132b are aligned with each other in the axial direction AD.

[0092] In the circumferential direction CD, the width dimension of the second flow passage 132 is the same as the second interval D2. The width dimension of the second flow passage 132 is smallest at the second upstream port 132a. The width dimension of the second upstream port 132a is the same as the interval D2a. The width dimension of the second flow passage 132 is largest at the second downstream port 132b. The width dimension of the second downstream port 132b is the same as the interval D2b.

[0093] The cross-sectional area of ​​the second flow path 132 gradually increases from the second upstream port 132a toward the second downstream port 132b. The cross-sectional area of ​​the second flow path 132 is the area of ​​the second flow path 132 on a plane obtained by cutting the second flow path 132 in a direction perpendicular to the axial direction AD. In the second flow path 132, the second upstream port area S132a is the smallest. The second upstream port area S132a is the open area of ​​the second upstream port 132a. The second upstream port area S132a is sometimes referred to as the cross-sectional area of ​​the second upstream port 132a. In the second flow path 132, the second downstream port area S132b is the largest. The second downstream port area S132b is the open area of ​​the second downstream port 132b. The second downstream port area S132b is sometimes referred to as the cross-sectional area of ​​the second downstream port 132b.

[0094] In the first flow path 131 and the second flow path 132, the first downstream port 131b and the second upstream port 132a are aligned in the axial direction AD. The first downstream port 131b opens in the axial direction AD toward the outer peripheral downstream end 910b. The first downstream port 131b corresponds to a first opposing port. The second upstream port 132a opens in the axial direction AD toward the outer peripheral upstream end 910a. The second upstream port 132a corresponds to a second opposing port. The first downstream port 131b and the second upstream port 132a are not offset in the circumferential direction CD. For example, one of the first downstream port 131b and the second upstream port 132a does not protrude further in the circumferential direction CD than the other. The width dimension of the first downstream port 131b and the width dimension of the second upstream port 132a are the same. The first downstream port area S131b and the second upstream port area S132a are the same.

[0095] The first upstream port 131a and the second downstream port 132b are aligned in the axial direction AD. The first upstream port 131a and the second downstream port 132b are not misaligned in the circumferential direction CD. For example, one of the first upstream port 131a and the second downstream port 132b does not protrude further in the circumferential direction CD than the other. The width dimension of the first upstream port 131a and the width dimension of the second downstream port 132b are the same. The first upstream port area S131a and the second downstream port area S132b are the same.

[0096] The connection flow path 133 connects the plurality of first flow paths 131 and the plurality of second flow paths 132. The connection flow path 133 extends in the circumferential direction CD so as to span the plurality of first flow paths 131. The connection flow path 133 connects two first flow paths 131 that are adjacent in the circumferential direction CD. The first downstream port 131b is included in the boundary between the connection flow path 133 and the first flow path 131. The connection flow path 133 extends in the circumferential direction CD so as to span the plurality of second flow paths 132. The connection flow path 133 connects two second flow paths 132 that are adjacent in the circumferential direction CD. The second upstream port 132a is included in the boundary between the connection flow path 133 and the second flow path 132.

[0097] The connection flow path 133 is open toward the upstream side, downstream side, and outer periphery. The connection flow path 133 includes a space between the first fin 921 and the second fin 922. This space is formed by the first downstream end 113 and the second upstream end 122. The connection flow path 133 includes a space connecting the first flow path 131 and the second flow path 132. In the axial direction AD, the width dimension of the connection flow path 133 is the same as the third distance D3. The width dimension of the connection flow path 133 is larger than the width dimension of the first downstream port 131b and the width dimension of the second upstream port 132a. The width dimension of the connection flow path 133 is smaller than the width dimension of the first upstream port 131a and the width dimension of the second downstream port 132b.

[0098] As shown in FIG. 8 , when the propeller wind Wp flows into the fin flow passage 130, mainstream regions R11, R21 and thermal boundary layers R12, R22 may be formed in the fin flow passage 130. If the inverter housing 90 rises due to heat generated in the inverter unit 170, a temperature difference is likely to occur between the propeller wind Wp flowing into the fin flow passage 130 and the inverter fins 92. The mainstream regions R11, R21 are regions where the propeller wind Wp, which has a temperature difference with the inverter fins 92, easily flows. The thermal boundary layers R12, R22 are regions where the temperature of the propeller wind Wp is likely to change due to heat from the inverter fins 92. The thermal boundary layers R12, R22 are formed so as to extend in layers along the outer surfaces of the inverter fins 92. The thermal boundary layers R12, R22 are sometimes referred to as thermal boundary regions. The mainstream regions R11, R21 are sometimes referred to as mainstream temperature regions.

[0099] The propeller wind Wp includes a first propeller wind Wp1. The first propeller wind Wp1 is the propeller wind Wp that flows through the first flow path 131. The first propeller wind Wp1 flows into the first flow path 131 from the first upstream port 131a. The first propeller wind Wp1 flows through the first flow path 131 in the axial direction AD.

[0100] In the first flow path 131, the flow of the first propeller wind Wp1 may form a first mainstream region R11 and a first thermal boundary layer R12. The first thermal boundary layer R12 is formed so as to extend in a layered manner in the axial direction AD along the first fin surface 111. For example, the thickness of the first thermal boundary layer R12 gradually increases in the circumferential direction CD from the first upstream port 131a to the first downstream port 131b. The first mainstream region R11 is located on the opposite side of the first thermal boundary layer R12 from the first fin 921 in the circumferential direction CD. The first mainstream region R11 is formed between two first thermal boundary layers R12 adjacent to each other in the circumferential direction CD. For example, the width of the first mainstream region R11 gradually decreases in the circumferential direction CD from the first upstream port 131a to the first downstream port 131b.

[0101] As shown in FIG. 9 , the first propeller wind Wp1 includes a first mainstream wind Wp11 and a first boundary wind Wp12. The first mainstream wind Wp11 flows in the axial direction AD through the first mainstream region R11 toward the first downstream port 131b. The first boundary wind Wp12 flows in the axial direction AD through the first temperature boundary layer R12 toward the first downstream port 131b. The temperature of the first boundary wind Wp12 is likely to increase in the first temperature boundary layer R12. The temperature of the first boundary wind Wp12 is likely to be higher than the temperature of the first mainstream wind Wp11. In other words, a temperature difference is likely to occur between the first boundary wind Wp12 and the first mainstream wind Wp11.

[0102] 8, the propeller wind Wp includes a second propeller wind Wp2. The second propeller wind Wp2 is the propeller wind Wp that flows through the second flow path 132. The second propeller wind Wp2 flows into the second flow path 132 from the second upstream port 132a. The second propeller wind Wp2 flows through the second flow path 132 in the axial direction AD.

[0103] In the second flow path 132, the flow of the second propeller wind Wp2 may form a second mainstream region R21 and a second thermal boundary layer R22. The second thermal boundary layer R22 is formed so as to extend in a layered manner in the axial direction AD along the second fin surface 121. For example, the thickness of the second thermal boundary layer R22 gradually increases in the circumferential direction CD from the second upstream port 132a toward the second downstream port 132b. The second mainstream region R21 is located on the opposite side of the second fin 922 in the circumferential direction CD across the second thermal boundary layer R22. The second mainstream region R21 is the space between two second thermal boundary layers R22 adjacent to each other in the circumferential direction CD.

[0104] As shown in Fig. 9, the second propeller wind Wp2 includes a second mainstream wind Wp21 and a second boundary wind Wp22. The second mainstream wind Wp21 flows in the axial direction AD through the second mainstream region R21 toward the second downstream port 132b. The second boundary wind Wp22 flows in the axial direction AD through the second thermal boundary layer R22 toward the second downstream port 132b. The temperature of the second boundary wind Wp22 is likely to increase in the second thermal boundary layer R22. The temperature of the second boundary wind Wp22 is likely to be higher than the temperature of the second mainstream wind Wp21. In other words, a temperature difference is likely to occur between the second boundary wind Wp22 and the second mainstream wind Wp21.

[0105] For example, consider Comparative Example 1, in which the first boundary wind Wp12, which had been flowing through the first thermal boundary layer R12, continues to flow in the axial direction AD and flows through the second thermal boundary layer R22 as the second boundary wind Wp22 due to the absence of turbulence such as vortices in the propeller wind Wp in the fin flow path 130. In Comparative Example 1, the first boundary wind Wp12 further increases in temperature in the second thermal boundary layer R22 as the second boundary wind Wp22. Therefore, the temperature difference between the second boundary wind Wp22 and the second mainstream wind Wp21 is likely to be larger than the temperature difference between the first boundary wind Wp12 and the first mainstream wind Wp11. In this case, the second thermal boundary layer R22 is likely to thicken in the circumferential direction CD. Furthermore, in this case, the second mainstream region R21 is likely to narrow in the circumferential direction CD. Therefore, in the second flow path 132, there is a concern that the high temperature of the second boundary air Wp22 will reduce the heat dissipation effect of the second fins 922 due to the second boundary air Wp22.

[0106] In contrast, in the present embodiment, the connection flow path 133 is provided between the first flow path 131 and the second flow path 132, which makes it easier for turbulence to occur in the propeller wind Wp. For example, when the first propeller wind Wp1 flows into the connection flow path 133 from the first downstream port 131b, the first propeller wind Wp1 is likely to separate from the first downstream end 113, causing turbulence to occur in the first propeller wind Wp1. In this case, the first mainstream wind Wp11 and the first boundary wind Wp12 flow into the connection flow path 133 as the first propeller wind Wp1. The first mainstream wind Wp11 and the first boundary wind Wp12 are likely to be agitated by turbulence that occurs when they flow into the connection flow path 133.

[0107] With regard to the connection flow path 133, the width dimension of the first downstream port 131b, the width dimension of the second upstream port 132a, the width dimension of the connection flow path 133, and the like are set to values ​​that make it easy to stir the first propeller wind Wp1 that flows into the connection flow path 133. For example, if the width dimension of the connection flow path 133 is too small, the first propeller wind Wp1 that flows into the connection flow path 133 may not be stirred easily. In other words, the amount of stirring of the first propeller wind Wp1 may be insufficient. If the width dimension of the connection flow path 133 is appropriately large, the first propeller wind Wp1 that flows into the connection flow path 133 is easily stirred. In other words, the amount of stirring of the first propeller wind Wp1 is less likely to be insufficient. In addition, the width dimension W1b of the first downstream end 113, the width dimension W2a of the second upstream end 122, the shape and size of the first fin 921, and the shape and size of the second fin 922 are also set so as to make it easier to stir the first propeller wind Wp1 that flows into the connecting flow path 133.

[0108] The propeller wind Wp includes a third propeller wind Wp3. The third propeller wind Wp3 is the propeller wind Wp that flows through the connecting flow path 133. The third propeller wind Wp3 includes the first propeller wind Wp1 that flows from the first flow path 131 into the connecting flow path 133. That is, the third propeller wind Wp3 includes the first mainstream wind Wp11 and the first boundary wind Wp12. The third propeller wind Wp3 tends to mix the first mainstream wind Wp11 and the first boundary wind Wp12. Therefore, the temperature of the third propeller wind Wp3 tends to become uniform in the connecting flow path 133.

[0109] The third propeller wind Wp3 flows from the connecting flow path 133 into the second flow path 132, and thereby flows through the second flow path 132 as the second propeller wind Wp2. The third propeller wind Wp3 that flows into the second mainstream region R21 flows through the second mainstream region R21 as the second mainstream wind Wp21. The third propeller wind Wp3 that flows into the second thermal boundary layer R22 flows through the second thermal boundary layer R22 as the second boundary wind Wp22. As described above, the temperature of the third propeller wind Wp3 is uniformized, and therefore the temperature of the second mainstream wind Wp21 that flows into the second mainstream region R21 and the temperature of the second boundary wind Wp22 that flows into the second thermal boundary layer R22 are substantially the same.

[0110] For this reason, in this embodiment, the temperature of the second boundary air Wp22 is likely to be lower than in Comparative Example 1. In this case, the second thermal boundary layer R22 is likely to be thinner in the circumferential direction CD than in Comparative Example 1. Also, in this case, the second mainstream region R21 is likely to be thicker in the circumferential direction CD than in Comparative Example 1. Therefore, the heat dissipation effect of the second fins 922 by the second boundary air Wp22 is improved compared to Comparative Example 1.

[0111] Next, consider Comparative Example 2, in which the fin flow path 130 does not have the second flow path 132 and the connecting flow path 133. In Comparative Example 2, as shown in FIG. 10 , a comparative fin 921ex is provided on the inverter outer peripheral surface 910 as the inverter fin 92. The comparative fin 921ex extends across the inverter section 170 in the axial direction AD. In Comparative Example 2, a comparative flow path 130ex is formed by two comparative fins 921ex adjacent to each other in the circumferential direction CD. The comparative flow path 130ex does not include a flow path corresponding to the connecting flow path 133.

[0112] In the comparative flow path 130ex, the comparative wind Wpex flows in the axial direction AD along the comparative fin 921ex. In the comparative flow path 130ex, the flow of the comparative wind Wpex forms a comparative mainstream region Rex1 and a comparative temperature boundary layer Rex2. As shown in FIG. 11 , the comparative wind Wpex includes a comparative mainstream wind Wpex1 and a comparative boundary wind Wpex2. The comparative mainstream wind Wpex1 flows through the comparative mainstream region Rex1. The comparative boundary wind Wpex2 flows through the comparative temperature boundary layer Rex2.

[0113] In the comparison flow path 130ex, the comparison mainstream air Wpex1 and the comparison boundary air Wpex2 are not easily mixed until the comparison air Wpex flowing in from the upstream side flows out to the downstream side. Therefore, in the comparison flow path 130ex, the temperature difference between the comparison mainstream air Wpex1 and the comparison boundary air Wpex2 is likely to increase as the comparison air Wpex moves downstream. Therefore, in Comparative Example 2, there is a concern that the heat dissipation effect of the comparison fins 921ex due to the comparison air Wpex will be insufficient as the comparison air Wpex moves downstream of the comparison flow path 130ex. There is also a concern that the heat dissipation effect of the inverter unit 170 due to the comparison air Wpex will be insufficient.

[0114] The inverter fins 92 of this embodiment will now be described. There is a strong demand for weight reduction in the electric vertical take-off and landing aircraft, the eVTOL 10. Therefore, weight reduction in the EPU 50 is achieved by reducing the size of the inverter housing 90 and other enclosures, and by reducing the number of parallel-connected semiconductor elements, such as the arm switch 86. To reduce the weight of the EPU 50, it is preferable to apply a cooling structure with low airflow pressure loss and high cooling performance to an air-cooled enclosure.

[0115] 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 cooling in order 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.

[0116] In the inverter device 80 mounted on the eVTOL 10, heat-generating components such as the switch component 175 may be located in one location facing the main flow direction of airflow such as propeller wind Wp. Also, the inverter device 80 may have low thermal diffusivity due to factors such as the thin thickness of the housing. In response to these issues, it has been discovered that the performance of the EPU 50 is more likely to be improved by improving the local cooling performance of the housing, rather than by increasing the surface area of ​​heat dissipation fins such as the inverter fins 92 to improve the heat dissipation performance of the housing.

[0117] In contrast, in this embodiment, the inverter fins 92 are provided on the inverter housing 90 in a state where they are divided into multiple pieces in the axial direction AD. That is, the inverter fins 92 are configured as divided into first fins 921 and second fins 922. With this configuration, the airflow is turbulent in the space between the first fins 921 and the second fins 922, which tends to mix the higher-temperature airflow flowing near the first fin 921 with the lower-temperature airflow flowing away from the first fin 921. This tends to lower the temperature of the airflow flowing near the second fin 922. That is, the second thermal boundary layer R22 formed along the second fin 922 tends to become thinner. This improves the cooling performance of the second fin 922.

[0118] Furthermore, with this configuration, because the first fin 921 and the second fin 922 are separated, a non-installation area where no heat dissipation fins are installed can be formed between the first fin 921 and the second fin 922. Therefore, the mass of the inverter fins 92 is reduced by the amount of the non-installation area, thereby reducing the weight of the EPU 50.

[0119] Furthermore, the first fins 921 are tapered so that the area of ​​the first flow path 131 decreases toward the heat generating element of the inverter unit 170. With this configuration, the first propeller wind Wp1 flows faster in the first flow path 131 closer to the first downstream port 131b. That is, in the first flow path 131, the flow velocity of the first propeller wind Wp1 tends to increase the closer to the inverter unit 170. When the flow velocity of the first propeller wind Wp1 increases in this manner, the heat transfer coefficient of the first flow path 131 tends to increase. Therefore, the heat dissipation performance of the inverter housing 90 due to the first propeller wind Wp1 can be improved. Furthermore, the increased heat transfer coefficient of the first flow path 131 can improve the thermal conductance.

[0120] Furthermore, with this configuration, the first main stream wind Wp11 and the first boundary wind Wp12 are likely to mix in the connecting flow path 133 due to the high flow velocity of the first propeller wind Wp1 flowing from the first flow path 131 into the connecting flow path 133. In this way, the first flow path 131 becomes narrower as it approaches the connecting flow path 133, so that a configuration can be realized in which the third propeller wind Wp3 is likely to be stirred in the connecting flow path 133.

[0121] Furthermore, with this configuration, the flow velocity of the first propeller wind Wp1 tends to increase the closer to the inverter unit 170 in the first flow path 131. This increases the heat transfer coefficient of the first propeller wind Wp1, and makes it easier for heat from the inverter unit 170 to be released from the inverter outer peripheral wall 95 and the first fins 921 to the first propeller wind Wp1. This therefore improves the heat dissipation performance of the heat-generating unit via the first propeller wind Wp1.

[0122] According to the present embodiment described so far, the first fin 921 and the second fin 922 are spaced apart in a direction perpendicular to the axial direction AD. In this configuration, turbulence such as vortexes is likely to occur in the propeller wind Wp flowing through the space between the first fin 921 and the second fin 922 at positions aligned with the inverter unit 170 in the radial direction RD. This facilitates heat dissipation from the inverter unit 170 to the outside of the inverter housing 90 via the first fin 921, the second fin 922, and the inverter outer peripheral wall 95. In other words, the turbulence in the propeller wind Wp can be utilized to enhance the heat dissipation effect of the first fin 921, the second fin 922, and the inverter outer peripheral surface 910. By locally generating turbulence in the propeller wind Wp at positions aligned with the inverter unit 170 in the radial direction RD on the outside of the inverter housing 90, an increase in pressure loss throughout the fin flow path 130 can be suppressed. Therefore, it is possible to improve the heat dissipation effect of the inverter unit 170 by the propeller wind Wp while preventing a shortage of the amount of propeller wind Wp flowing through the fin flow passages 130. As described above, the heat dissipation effect of the inverter housing 90 in the EPU 50 can be improved by the inverter fins 92.

[0123] According to this embodiment, the first distance D1 between two first fins 921 adjacent to each other in the circumferential direction CD gradually decreases toward the outer circumferential downstream end 910b. In this configuration, the width dimension of the first flow path 131 decreases as it approaches the inverter unit 170. Therefore, in the first flow path 131, the flow velocity of the first propeller wind Wp1 tends to increase as it approaches the inverter unit 170. Therefore, the cooling effect of the first propeller wind Wp1 can be locally enhanced at a position overlapping the inverter unit 170 in the axial direction AD.

[0124] According to this embodiment, the width dimension W1 of the first fin 921 in the circumferential direction CD gradually increases toward the outer circumferential downstream end 910b. That is, the first fin 921 is an expanding fin. This makes it possible to realize a configuration in which the width dimension of the first flow path 131 decreases the closer it is to the outer circumferential downstream end 910b. That is, it is possible to realize a configuration in which the cooling effect of the first propeller airflow Wp1 is locally increased relative to the installation position of the inverter unit 170.

[0125] According to this embodiment, the first downstream port 131b and the second upstream port 132a are aligned in the axial direction AD in the fin flow path 130. With this configuration, turbulence is likely to occur in the propeller wind Wp that flows from the first downstream port 131b into the connecting flow path 133, while the propeller wind Wp that flows from the first downstream port 131b into the connecting flow path 133 is likely to flow out from the second upstream port 132a. Therefore, in the connecting flow path 133, turbulence in the propeller wind Wp improves the cooling effect of the inverter unit 170, while the presence of the connecting flow path 133 can prevent an excessive increase in pressure loss in the fin flow path 130. Therefore, the heat dissipation effect of the inverter housing 90 can be improved by both the turbulence in the propeller wind Wp and the increased speed of the propeller wind Wp.

[0126] According to the present embodiment, the switch component 175 is provided on the inverter inner circumferential surface 913. The first fin 921 and the second fin 922 extend in the axial direction AD from a position aligned with the switch component 175 in the radial direction RD. In this configuration, a connection flow path 133, which is a space between the first fin 921 and the second fin 922, is provided at a position aligned with the switch component 175 in the radial direction RD. Therefore, in the connection flow path 133, turbulence of the propeller wind Wp is locally generated, thereby improving the cooling performance of the switch component 175.

[0127] 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.

[0128] 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.

[0129] Second Embodiment In the first embodiment, the width dimension W1b of the first downstream end 113 and the width dimension W2a of the second upstream end 122 are the same. In contrast, in the second embodiment, the width dimension W2a of the second upstream end 122 is larger than the width dimension W1b of the first downstream end 113. Configurations, actions, and effects 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.

[0130] As shown in FIG. 12 , in this embodiment, the second outer peripheral fins are parallel fins. The inverter fins 92 include second parallel fins 922A as the second outer peripheral fins. The second parallel fins 922A have a different shape from the second fins 922 of the first embodiment. In the second parallel fins 922A, a pair of second fin surfaces 121 extend parallel to the axial direction AD. The pair of second fin surfaces 121 extend parallel to the motor axis Cm. The second parallel fins 922A have a uniform width dimension W2. For example, in the second parallel fins 922A, the width dimension W2a of the second upstream end 122 and the width dimension W2b of the second downstream end 123 are the same. The second parallel fins 922A are sometimes referred to as parallel fins or straight fins.

[0131] The second spacing D2 is uniform between two second parallel fins 922A adjacent to each other in the circumferential direction CD. For example, the upstream end spacing D2a and the downstream end spacing D2b are the same between two second parallel fins 922A adjacent to each other in the circumferential direction CD. Furthermore, the width dimensions of the second flow paths 132 are uniform. For example, the width dimensions of the second upstream openings 132a and the width dimensions of the second downstream openings 132b are the same. Furthermore, the cross-sectional areas of the second flow paths 132 are uniform. For example, the second upstream opening area S132a and the second downstream opening area S132b are the same.

[0132] The first downstream end 113 and the second upstream end 122 have different width dimensions in the circumferential direction CD, and are therefore offset in the circumferential direction CD. For example, the width dimension W1b of the first downstream end 113 is different from the width dimension W2a of the second upstream end 122. The first downstream end 113 protrudes from the second upstream end 122 on at least one side in the circumferential direction CD. For example, the first downstream end 113 protrudes from the second upstream end 122 on both sides in the circumferential direction CD. The first downstream end 113 protrudes from the second upstream end 122 on both sides in the circumferential direction CD. The first downstream end 113 corresponds to a first opposing end. The second upstream end 122 corresponds to a second opposing end.

[0133] The width of the first downstream opening 131b is different from the width of the second upstream opening 132a. For example, the width of the second upstream opening 132a is larger than the width of the first downstream opening 131b. The first downstream opening area S131b is different from the second upstream opening area S132a. For example, the second upstream opening area S132a is larger than the first downstream opening area S131b.

[0134] The second parallel fins 922A will now be described in detail. For the EPU 50 mounted on the eVTOL 10, in addition to heat dissipation performance, the pressure loss of the refrigerant flowing between the heat dissipation fins is also an important performance factor. In contrast, the second parallel fins 922A have a second upstream end 122 that is thinner in the circumferential direction CD than the first downstream end 113. By thinning the second parallel fins 922A, the cross-sectional area of ​​the second flow passages 132 is increased, thereby improving pressure loss in the second flow passages 132. Furthermore, the two second fin surfaces 121 that face each other across the second flow passages 132 extend parallel to each other in the axial direction AD, thereby improving pressure loss in the second flow passages 132.

[0135] Of the two heat dissipation fins aligned in the axial direction AD, the first fin 921, which is the upstream heat dissipation fin, is an extended fin, which increases the flow rate of the propeller wind Wp flowing through the first flow path 131, which is the upstream flow path. Furthermore, the second parallel fin 922A, which is the downstream heat dissipation fin, is thinner than the first fin 921. Therefore, the propeller wind Wp, whose flow rate has been increased by the first fin 921, can generate a fast flow in the fin division due to its inertia. This promotes mixing of the propeller wind Wp in the fin division. The fin division is the portion where the inverter fin 92 is divided. For example, the fin division is the portion between an upstream fin, such as the first fin 921, and a downstream fin, such as the second parallel fin 922A.

[0136] Since the second parallel fins 922A are thinner than the first fins 921, the second parallel fins 922A can be made lighter than the first fins 921. In this way, the fin mass is reduced by the amount of the weight reduction of the second parallel fins 922A, which contributes to reducing the weight of the EPU 50 and the inverter housing 90.

[0137] According to this embodiment, the first downstream port 131b and the second upstream port 132a are offset in the circumferential direction CD. This configuration makes it less likely that the propeller wind Wp that flows from the first downstream port 131b into the connecting flow path 133 will flow from the connecting flow path 133 to the first upstream port 131a without being stirred. For example, when the propeller wind Wp flows from the first downstream port 131b into the connecting flow path 133, the propeller wind Wp is easily separated from the first downstream end 113 and is therefore easily stirred in the connecting flow path 133. This makes it less likely that a temperature difference will occur in the connecting flow path 133. This makes it possible to prevent the heat dissipation effect of the inverter unit 170 due to the propeller wind Wp from varying depending on the location of the inverter unit 170.

[0138] According to this embodiment, the width dimension W2a of the second upstream end 122 is smaller than the width dimension W1b of the first downstream end 113. With this configuration, a configuration can be realized in which the second upstream opening area S132a is smaller than the first downstream opening area S131b. This makes it easier for the propeller wind Wp to flow from the connection flow path 133 to the second upstream opening 132a. In other words, it is possible to reduce pressure loss for the propeller wind Wp that flows from the first downstream opening 131b through the connection flow path 133 to the second upstream opening 132a.

[0139] <Third Embodiment> In the first embodiment, the first flow passage 131 and the second flow passage 132 are aligned in the axial direction AD. In contrast, in the third embodiment, the first flow passage 131 and the second flow passage 132 are formed at positions offset in the circumferential direction CD. Configurations, actions, and effects not specifically described in the third embodiment are the same as those in the first embodiment. In the third embodiment, differences from the first embodiment will be mainly described.

[0140] As shown in FIG. 13 , the first fin 921 and the second fin 922 are positioned such that they are offset in the circumferential direction CD. That is, the first fin 921 and the second fin 922 are offset in the circumferential direction CD. The first fin 921 is aligned with the second flow path 132 in the axial direction AD. The second fin 922 is aligned with the first flow path 131 in the axial direction AD. The first flow path 131 and the second flow path 132 are positioned such that they are spaced apart in the circumferential direction CD. The first downstream port 131b and the second upstream port 132a are positioned such that they are spaced apart in the circumferential direction CD. Note that a portion of the first downstream port 131b and a portion of the second upstream port 132a may be aligned in the axial direction AD.

[0141] The first downstream end 113 and the second upstream end 122 are positioned at different positions in the circumferential direction CD, and are therefore offset in the circumferential direction CD. For example, a portion of the first downstream end 113 and a portion of the second upstream end 122 are aligned in the axial direction AD. The first downstream end 113 is bridged over two second upstream ends 122 that are adjacent to each other in the circumferential direction CD. The first downstream end 113 is provided at a position aligned with the second upstream port 132a in the axial direction AD. The second upstream end 122 is provided at a position aligned with the first downstream port 131b in the axial direction AD.

[0142] According to this embodiment, the second upstream end 122 is provided at a position aligned with the first downstream port 131b in the axial direction AD. In this configuration, the propeller wind Wp that flows from the first downstream port 131b into the connecting flow path 133 advances toward the second upstream end 122. The propeller wind Wp approaches or collides with the second upstream end 122, promoting mixing and stirring of the propeller wind Wp in the connecting flow path 133. This makes it possible to uniformize the temperature of the propeller wind Wp in the connecting flow path 133.

[0143] In this embodiment, the width of the connection flow path 133 may be smaller than the width of the first downstream port 131b or the width of the second upstream port 132a. That is, the cross-sectional area of ​​the connection flow path 133 may be smaller than the first downstream port area S131b or the second upstream port area S132a. In this configuration, the connection flow path 133 narrows the fin flow path 130 more than the first downstream port 131b or the second upstream port 132a. Therefore, in a configuration in which the first downstream end 113 and the second upstream end 122 are offset in the circumferential direction CD, the flow velocity of the propeller wind Wp that flows from the first downstream port 131b into the connection flow path 133 tends to increase as it flows through the connection flow path 133 in the circumferential direction CD. Therefore, the flow velocity of the propeller wind Wp increases at a position aligned with the inverter unit 170 in the radial direction RD, thereby improving the heat dissipation performance of the inverter unit 170 due to the propeller wind Wp.

[0144] <Fourth Embodiment> In a fourth embodiment, the inverter housing 90 is covered from the outer periphery by a duct member. The configuration, operation, 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.

[0145] As shown in FIG. 14 , the EPU 50 has an outer circumferential duct 200. The outer circumferential duct 200 covers the inverter housing 90 from the outer periphery. The outer circumferential duct 200 is sometimes referred to as a duct member or an outer cylinder. The outer circumferential duct 200 has a duct body 201 and duct fins 202. The duct body 201 and the duct fins 202 are formed from a resin material or the like. The duct body 201 and the duct fins 202 have thermal conductivity. Note that the duct body 201 and the duct fins 202 may be formed from a metal material.

[0146] The duct main body 201 is formed in a cylindrical shape and extends in the axial direction AD. The duct main body 201 extends in the circumferential direction CD so as to span the multiple inverter fins 92. The duct main body 201 is provided on the outer circumferential side of the inverter outer circumferential surface 910 via the inverter fins 92. The duct main body 201 covers the inverter outer circumferential surface 910 from the outer circumferential side. The duct main body 201 is provided in a position close to or in contact with the inverter fins 92 in the radial direction RD. The fin flow paths 130 are formed between the inverter outer circumferential surface 910 and the duct main body 201. The fin flow paths 130 are formed between the duct main body 201 and the inverter outer circumferential surface 910. The duct main body 201 corresponds to a duct portion, and the fin flow paths 130 correspond to an outer circumferential flow path.

[0147] The duct main body 201 has a duct outer peripheral surface 201a and a duct inner peripheral surface 201b. The duct outer peripheral surface 201a and the duct inner peripheral surface 201b are formed in an annular shape and extend in the axial direction AD. The duct outer peripheral surface 201a is the outer peripheral surface of the duct main body 201. The duct inner peripheral surface 201b is the inner peripheral surface of the duct main body 201. The duct inner peripheral surface 201b faces the inverter outer peripheral surface 910 via the inverter fins 92. The fin flow path 130 is formed by the duct inner peripheral surface 201b and the inverter outer peripheral surface 910.

[0148] The duct fins 202 are provided on the duct inner peripheral surface 201b. The duct fins 202 are formed in a plate shape and extend in a direction perpendicular to the circumferential direction CD. The duct fins 202 extend from the duct inner peripheral surface 201b toward the inverter outer peripheral surface 910. The duct fins 202 are convex portions that protrude inward from the duct inner peripheral surface 201b. The duct fins 202 extend in the axial direction AD along the duct inner peripheral surface 201b. Multiple duct fins 202 are arranged in the circumferential direction CD along the duct inner peripheral surface 201b.

[0149] At least a portion of the duct fin 202 is provided between two adjacent inverter fins 92 in the circumferential direction CD. The duct fin 202 is positioned between the two adjacent inverter fins 92 in the circumferential direction CD from the outer periphery. In other words, the duct fin 202 is positioned in the fin flow path 130 from the outer periphery. The duct fins 202 and the inverter fins 92 are arranged alternately in the circumferential direction CD.

[0150] As shown in Figures 15 to 17, the duct fin 202 has a pair of duct fin surfaces 203. The duct fin surfaces 203 are plate surfaces of the duct fin 202. The pair of duct fin surfaces 203 extend in a direction perpendicular to the circumferential direction CD and are aligned in the circumferential direction CD. The duct fin surfaces 203 are also side surfaces of the duct fin 202 and are sometimes referred to as fin side surfaces. The duct fin surfaces 203 have an upstream fin surface 202a and a downstream fin surface 202b. The upstream fin surface 202a and the downstream fin surface 202b are aligned in the axial direction AD. For example, the upstream fin surface 202a extends upstream from the downstream fin surface 202b.

[0151] The duct fin 202 has a pair of ends aligned in the axial direction AD, a fin upstream end 204 and a fin downstream end 205. The fin upstream end 204 is the upstream end of the duct fin 202. The fin downstream end 205 is the downstream end of the duct fin 202.

[0152] The duct fin 202 has a shape in which a middle portion in the axial direction AD bulges in the circumferential direction CD. In the circumferential direction CD, the width dimension of the duct fin 202 gradually decreases from the middle portion toward the upstream end 204 of the fin and the downstream end 205 of the fin.

[0153] At least one of the upstream fin surface 202a and the downstream fin surface 202b is inclined in the circumferential direction CD with respect to the motor axis Cm. For example, the upstream fin surface 202a is inclined to one side in the circumferential direction CD with respect to the motor axis Cm. The downstream fin surface 202b is inclined to the other side in the circumferential direction CD with respect to the motor axis Cm. The upstream fin surface 202a and the downstream fin surface 202b extend straight in the axial direction AD. The upstream fin surface 202a and the downstream fin surface 202b are tapered surfaces.

[0154] As shown in Figure 15, the duct fin 202 has a shape in which the width in the circumferential direction CD gradually decreases toward the inner periphery. The duct fin 202 corresponds to a tapered fin. The width dimension of the duct fin 202 continuously decreases toward the inverter outer periphery surface 910. The distance between a pair of duct fin surfaces 203 gradually decreases toward the tip of the duct fin 202. The duct fin surfaces 203 are inclined in the circumferential direction CD with respect to the outer periphery center line Crd. The duct fin surfaces 203 extend straight toward the inner periphery. The duct fin surfaces 203 are tapered surfaces.

[0155] The duct fins 202 may be tapered in stages toward the inner periphery. For example, the duct fin surface 203 may be a stepped surface. The duct fin surface 203 may also be curved so as to be concave or convex in the circumferential direction CD. For example, the duct fin surface 203 may be a curved or bent surface.

[0156] In this embodiment, the inverter fins 92 also have a tapered shape, similar to the duct fins 202. The inverter fins 92 have a shape in which the width in the circumferential direction CD gradually decreases toward the inner periphery. The first fin surface 111 and the second fin surface 121 are inclined in the circumferential direction CD with respect to the outer periphery center line Crd. The inclination angles of the first fin surface 111 and the second fin surface 121 with respect to the outer periphery center line Crd are the same as the inclination angle of the duct fin surface 203 with respect to the outer periphery center line Crd. In other words, the duct fin surface 203 extends in the radial direction RD parallel to the first fin surface 111 and the second fin surface 121.

[0157] 17 , the duct fin 202 is provided in the fin flow path 130. At least a portion of the duct fin 202 is provided in the connecting flow path 133 between the first downstream port 131b and the second upstream port 132a. The duct fin 202 extends from the connecting flow path 133 into at least one of the first flow path 131 and the second flow path 132. For example, the duct fin 202 extends in the axial direction AD so as to bridge between the first flow path 131 and the second flow path 132 via the connecting flow path 133. The fin upstream end 204 of the duct fin 202 is provided in the first flow path 131. The fin downstream end 205 is provided in the second flow path 132.

[0158] The duct fin 202 is interposed at least between two adjacent first fins 921 in the circumferential direction CD and between two adjacent second fins 922 in the circumferential direction CD. For example, the duct fin 202 is provided between two adjacent first fins 921 in the circumferential direction CD, and also between two adjacent second fins 922 in the circumferential direction CD. The duct fin 202 corresponds to a fin interposition portion.

[0159] 16 , at least a portion of the duct fins 202 are provided in a position aligned with the inverter unit 170 in the axial direction AD. The duct fins 202 are provided in a position aligned with the switch component 175 in the axial direction AD. For example, the duct fins 202 are provided in a position that does not protrude from the switch component 175 in the axial direction AD. The entire duct fins 202 are aligned with the switch component 175 in the axial direction AD.

[0160] As shown in FIG. 17 , in this embodiment, both the first and second outer peripheral fins are parallel fins. Similar to the second embodiment, the inverter fins 92 include second parallel fins 922A as the second outer peripheral fins. The inverter fins 92 include first parallel fins 921A as the first outer peripheral fins. The first parallel fins 921A have a different shape from the first fins 921 of the first embodiment. In the first parallel fin 921A, a pair of first fin surfaces 111 extend parallel to the axial direction AD. The pair of first fin surfaces 111 extend parallel to the motor axis Cm. The first parallel fin 921A has a uniform width W1. For example, in the first parallel fin 921A, the width W1a of the first upstream end 112 and the width W1b of the first downstream end 113 are the same. The first parallel fin 921A is sometimes referred to as a parallel fin or a straight fin.

[0161] The first distance D1 is uniform between two first parallel fins 921A adjacent to each other in the circumferential direction CD. For example, the upstream end distance D1a and the downstream end distance D1b are the same between two first parallel fins 921A adjacent to each other in the circumferential direction CD. Furthermore, the width dimensions of the first flow paths 131 are uniform. For example, the width dimensions of the first upstream openings 131a and the width dimensions of the first downstream openings 131b are the same. Furthermore, the cross-sectional areas of the first flow paths 131 are uniform. For example, the first upstream opening area S131a and the first downstream opening area S131b are the same.

[0162] In the first flow path 131, the distance between the first parallel fins 921A and the duct fins 202 in the circumferential direction CD gradually decreases from the fin upstream end 204 toward the first downstream port 131b in the axial direction AD. Therefore, even in a configuration in which two first fin surfaces 111 adjacent in the circumferential direction CD extend parallel to each other in the axial direction AD, the cross-sectional area of ​​the first flow path 131 gradually decreases toward the first downstream port 131b. The flow velocity of the first propeller wind Wp1 tends to increase as it passes between the first parallel fins 921A and the duct fins 202 and approaches the first downstream port 131b.

[0163] In the second flow passage 132, the distance between the second parallel fin 922A and the duct fin 202 in the circumferential direction CD gradually increases in the axial direction AD from the second upstream port 132a toward the fin downstream end 205. Therefore, even in a configuration in which two second fin surfaces 121 adjacent in the circumferential direction CD extend parallel to each other in the axial direction AD, the cross-sectional area of ​​the second flow passage 132 gradually increases toward the fin downstream end 205.

[0164] The outer periphery duct 200 will now be described in detail. By providing the outer periphery duct 200 on the outer periphery of the inverter housing 90, the propeller wind Wp flowing in the axial direction AD as a refrigerant flow is guided by the outer periphery duct 200. In the inverter device 80, by providing the duct fin 202 between the two heat dissipation fins, the flow path area between the two heat dissipation fins can be reduced without tapering the heat dissipation fins. Therefore, the duct fin 202 can improve heat dissipation performance around the fin division portion.

[0165] The inverter fins 92 become thinner toward the fin tips. That is, the inverter fins 92 become thinner in the circumferential direction CD the further they are from the inverter outer peripheral surface 910. Therefore, the first distance D1 and the second distance D2 become larger in regions farther outward from the inverter outer peripheral surface 910. In the fin flow paths 130, the cross-sectional area of ​​the region farther from the inverter outer peripheral surface 910 is larger than the cross-sectional area of ​​the region closer to the inverter outer peripheral surface 910.

[0166] In contrast, the duct fins 202 become thinner toward the fin tips. That is, the duct fins 202 become thinner the closer they are to the inverter outer peripheral surface 910. For this reason, the cross-sectional area of ​​the duct fins 202 at the portions farther from the inverter outer peripheral surface 910 is larger than the cross-sectional area of ​​the portions closer to the inverter outer peripheral surface 910. Therefore, in the actual region in the fin flow path 130 where the propeller wind Wp actually flows, the presence of the duct fins 202 reduces the cross-sectional area of ​​the region farther from the inverter outer peripheral surface 910 to approach the cross-sectional area of ​​the region closer to the inverter outer peripheral surface 910. This makes it possible to form a uniform flow in the fin flow path 130 regardless of the height of the heat dissipation fins such as the inverter fins 92.

[0167] According to this embodiment, at least a portion of the duct fins 202 is provided between the first downstream port 131b and the second upstream port 132a. In this configuration, when the propeller wind Wp flows from the first downstream port 131b into the connecting flow path 133, the propeller wind Wp is likely to be agitated by approaching or colliding with the duct fins 202. Therefore, with regard to the propeller wind Wp, turbulence such as vortices caused by the presence of the duct fins 202 can enhance the heat dissipation effect on the inverter unit 170.

[0168] According to this embodiment, the duct fins 202 extend in the radial direction RD from the duct body 201 toward the inverter outer peripheral surface 910. In this configuration, the outer peripheral duct 200 is attached to the inverter housing 90, and the duct fins 202 are provided in the fin flow paths 130. Therefore, the duct fins 202 can be arranged even in positions in the fin flow paths 130 where it is difficult to arrange the duct fins 202 on the inverter outer peripheral surface 910 due to reasons such as the convenience of manufacturing the inverter housing 90. This increases the degree of freedom in determining the positions at which fin intervening portions such as the duct fins 202 are arranged.

[0169] According to this embodiment, the width of the duct fins 202 in the circumferential direction CD gradually decreases toward the inverter outer peripheral surface 910. Therefore, even if the width dimension of the fin flow path 130 decreases closer to the inverter outer peripheral surface 910, the width dimension of the actual area of ​​the fin flow path 130 can be made uniform in the radial direction RD.

[0170] <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.

[0171] In each of the above embodiments, peripheral fins such as inverter fins 92 may be provided in any manner on a housing such as the inverter housing 90. Of the multiple inverter fins 92, at least one inverter fin 92 may be provided to correspond to a peripheral fin. Furthermore, first peripheral fins such as first fins 921 and second peripheral fins such as second fins 922 may be provided in any manner on the housing. Of the multiple first fins 921, at least one first fin 921 may be provided to correspond to the first peripheral fin. Of the multiple second fins 922, at least one second fin 922 may be provided to correspond to the second peripheral fin. Furthermore, at least a portion of the peripheral fin, first peripheral fin, and second peripheral fin may be provided on the inverter upstream surface 911 or the inverter downstream surface 912.

[0172] In each of the above embodiments, the first outer circumferential fins and the second outer circumferential fins may have any shape. For example, in the above first embodiment, the first fin 921 may be a contracting fin or a parallel fin. Also, the second fin 922 may be an expanding fin or a parallel fin. Furthermore, the shapes of the multiple first outer circumferential fins do not have to be uniform. Similarly, the shapes of the multiple second outer circumferential fins do not have to be uniform. In addition, the first outer circumferential fins and the second outer circumferential fins may be inclined in the circumferential direction CD with respect to the motor axis Cm.

[0173] In each of the above embodiments, the first and second outer fins may have any positional relationship as long as they extend in the axial direction AD from a position overlapping a heat-generating portion, such as the inverter unit 170, in the radial direction RD. The first and second outer fins may be spaced apart in a direction perpendicular to the radial direction RD. For example, in the first embodiment, the first fin 921 and the second fin 922 may be spaced apart in the circumferential direction CD. In this configuration, a portion of the first fin 921 and a portion of the second fin 922 may be aligned in the circumferential direction CD. For example, the first downstream end 113 may be located downstream of the second upstream end 122. In other words, the first flow path 131 and the second flow path 132 may be directly connected without the connecting flow path 133.

[0174] In each of the above embodiments, the relationship in size between the width dimension W1b of the first downstream end 113 and the width dimension W2a of the second upstream end 122 may be any. For example, the width dimension W1b of the first downstream end 113 may be larger than the width dimension W2a of the second upstream end 122. Furthermore, the relationship in size between the first downstream opening area S131b and the second upstream opening area S132a may be any. For example, the first downstream opening area S131b may be larger than the second upstream opening area S132a.

[0175] In each of the above embodiments, the fin interposition portion such as the duct fin 202 may have any shape. For example, in the above fourth embodiment, the duct fin 202 may be plate-shaped and extend in the circumferential direction CD. The duct fin 202 may also be formed in a cylindrical, prismatic, or tubular shape.

[0176] In each of the above embodiments, the fin interposition portion may be provided in any manner in the fin flow path 130. For example, in the above fourth embodiment, the duct fins 202 may be provided on the inverter outer peripheral surface 910. In this configuration, the protrusions provided on the inverter outer peripheral surface 910 are the duct fins 202 and correspond to the fin interposition portion.

[0177] In each of the above embodiments, the surface-mounted components may be arranged in any manner inside the housing. For example, in the first embodiment, the capacitor component 176 and the filter component 177 may be arranged as surface-mounted components. Furthermore, the heat-generating portion may not have a surface-mounted component. In this configuration, it is preferable that a plurality of heat-generating components, such as the switch component 175, are arranged along the inverter inner circumferential surface 913.

[0178] 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.

[0179] 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.

[0180] 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.

[0181] 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.

[0182] 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.

[0183] 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.

[0184] 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.

[0185] (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.

[0186] (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 the axial direction (AD) and accommodating the heat generating portion; and outer peripheral fins (92) that extend in the axial direction along the housing outer peripheral surface, are arranged in a circumferential direction (CD) of the housing along the housing outer peripheral surface, and release heat from the heat generating portion to the outside of the housing, wherein the housing outer peripheral surface has a first surface end (910a) and a second surface end (910b) as a pair of ends arranged in the axial direction, and the plurality of outer peripheral fins include: first outer peripheral fins (921, 921A) that extend from a position that is arranged in the radial direction (RD) of the housing to the heat generating portion toward the first of the first and second surface ends; A drive device having a second outer fin (922, 922A) that is located at a position away from the first outer fin in a direction perpendicular to the radial direction and extends from a position aligned radially with the heat generating portion toward the second surface end of the first surface end and the second surface end.

[0187] (Technical Concept 2) The drive device according to Technical Concept 1, wherein the distance (D1) between two of the first outer peripheral fins adjacent to each other in the circumferential direction gradually decreases toward the end of the second surface in the axial direction.

[0188] (Technical Idea 3) A drive device according to Technical Idea 1 or 2, in which the first outer peripheral fin is an expanding fin (921) whose circumferential width (W1) gradually expands toward the second surface end.

[0189] (Technical Idea 4) A drive device described in any one of Technical Ideas 1 to 3, wherein a first opposing opening (131b) that is open toward the second surface end side in the axial direction is formed between two of the first outer peripheral fins that are adjacent in the circumferential direction, and a second opposing opening (132a) that is open toward the first surface end side in the axial direction is formed between two of the second outer peripheral fins that are adjacent in the circumferential direction, and the first opposing opening and the second opposing opening are aligned in the axial direction.

[0190] (Technical Idea 5) A drive device according to Technical Idea 4, comprising a fin interposition portion (202) extending in the radial direction, at least a portion of which is provided between the first opposing opening and the second opposing opening, and interposed at least between two of the first outer peripheral fins adjacent in the circumferential direction and two of the second outer peripheral fins adjacent in the circumferential direction.

[0191] (Technical Idea 6) A drive device according to Technical Idea 5, comprising a duct portion (201) that is provided on the outer peripheral side of the housing outer peripheral surface via the outer peripheral fins so as to cover the outer peripheral surface of the housing from the outer peripheral side, and that forms an outer peripheral flow path (130) through which gas flows between the duct portion and the housing outer peripheral surface, and the fin interposition portion extends in the radial direction from the duct portion toward the housing outer peripheral surface.

[0192] (Technical Concept 7) The drive device according to Technical Concept 5 or 6, wherein the fin interposition portion is provided with a tapered fin (202) whose width in the circumferential direction gradually decreases toward the outer peripheral surface of the housing.

[0193] (Technical Idea 8) A drive device described in any one of Technical Ideas 1 to 7, wherein the first outer peripheral fin and the second outer peripheral fin are spaced apart in the axial direction, the first outer peripheral fin has a first opposing end (113) which is an end on the second surface end side, the second outer peripheral fin has a second opposing end (122) which is an end on the first surface end side, and the first opposing end and the second opposing end are offset in the circumferential direction.

[0194] (Technical Idea 9) A drive device described in any one of Technical Ideas 1 to 8, wherein the first outer peripheral fin and the second outer peripheral fin are spaced apart in the axial direction, the first outer peripheral fin has a first opposing end (113) that is an end on the second surface end side, the second outer peripheral fin has a second opposing end (122) that is an end on the first surface end side, the first opposing end and the second opposing end are aligned in the axial direction, and a width dimension (D2a) of the second opposing end in the circumferential direction is smaller than a width dimension (D1b) of the first opposing end.

[0195] (Technical Idea 10) A drive device described in any one of Technical Ideas 1 to 9, wherein the first outer peripheral fin and the second outer peripheral fin are spaced apart in the axial direction, a first opposing opening (131b) that is open toward the second surface end side in the axial direction is formed between two adjacent first outer peripheral fins in the circumferential direction, the second outer peripheral fin has a second opposing end (122) that is the end side of the first surface end side, and the second opposing end is located in a position aligned with the first opposing opening in the axial direction.

[0196] (Technical Idea 11) The heat generating portion has a plurality of surface-mounted components (175) arranged in the circumferential direction along the inner circumferential surface (913) of the housing and provided on the inner circumferential surface of the housing, the first outer peripheral fins extending from a position aligned radially on the surface-mounted components toward the first surface end, and the second outer peripheral fins extending from a position aligned radially on the surface-mounted components toward the second surface end, a drive device described in any one of Technical Ideas 1 to 10.

[0197] (Technical Idea 12) A drive device according to any one of Technical Ideas 1 to 11, 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.

[0198] (Technical Concept 13) The drive device according to any one of Technical Concepts 1 to 12, 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 in the axial direction along the housing outer peripheral surface, arranged in a circumferential direction (CD) of the housing along the housing outer peripheral surface, and dissipating heat from the heat generating portion to the outside of the housing, wherein the housing outer peripheral surface has a first surface end (910a) and a second surface end (910b) as a pair of ends aligned in the axial direction, and the plurality of outer peripheral fins include a first outer peripheral fin (921, 921A) extending from a position aligned in the radial direction (RD) of the housing to the heat generating portion toward the first of the first and second surface ends, a second outer circumferential fin (922, 922A) provided at a position away from the first outer circumferential fin in a direction perpendicular to the radial direction and extending from a position aligned radially with the heat generating portion toward one of the first surface end and the second surface end.

2. A drive unit as described in claim 1, wherein the distance (D1) between two of the first outer peripheral fins adjacent to each other in the circumferential direction gradually decreases in the axial direction toward the end of the second surface.

3. A drive unit as described in claim 1, wherein the first outer peripheral fin is an expansion fin (921) whose circumferential width (W1) gradually expands toward the second surface end.

4. A drive device as described in any one of claims 1 to 3, wherein a first opposing opening (131b) opening toward the second surface end side in the axial direction is formed between two of the first outer peripheral fins adjacent to each other in the circumferential direction, and a second opposing opening (132a) opening toward the first surface end side in the axial direction is formed between two of the second outer peripheral fins adjacent to each other in the circumferential direction, and the first opposing opening and the second opposing opening are aligned in the axial direction.

5. A drive unit as described in claim 4, further comprising a fin interposition portion (202) extending in the radial direction, at least a portion of which is provided between the first opposing opening and the second opposing opening, and interposed at least between two of the first outer peripheral fins adjacent to each other in the circumferential direction and two of the second outer peripheral fins adjacent to each other in the circumferential direction.

6. A drive unit as described in claim 5, further comprising a duct portion (201) that is provided on the outer peripheral side of the housing outer peripheral surface via the outer peripheral fins so as to cover the outer peripheral side of the housing outer peripheral surface, and that forms an outer peripheral flow path (130) through which gas flows between the duct portion and the housing outer peripheral surface, and the fin interposition portion extends in the radial direction from the duct portion toward the housing outer peripheral surface.

7. The drive unit according to claim 5, wherein the fin interposition portion is a tapered fin (202) whose circumferential width gradually decreases toward the outer circumferential surface of the housing.

8. A drive device as described in any one of claims 1 to 3, wherein the first outer circumferential fin and the second outer circumferential fin are spaced apart in the axial direction, the first outer circumferential fin has a first opposing end (113) which is an end portion on the second surface end side, and the second outer circumferential fin has a second opposing end (122) which is an end portion on the first surface end side, and the first opposing end and the second opposing end are offset in the circumferential direction.

9. A drive device as described in any one of claims 1 to 3, wherein the first outer circumferential fin and the second outer circumferential fin are separated in the axial direction, the first outer circumferential fin has a first opposing end (113) which is an end portion on the second surface end side, and the second outer circumferential fin has a second opposing end (122) which is an end portion on the first surface end side, the first opposing end and the second opposing end are aligned in the axial direction, and a width dimension (D2a) of the second opposing end in the circumferential direction is smaller than a width dimension (D1b) of the first opposing end.

10. A drive device as described in any one of claims 1 to 3, wherein the first outer circumferential fin and the second outer circumferential fin are spaced apart in the axial direction, a first opposing opening (131b) that is open toward the second surface end in the axial direction is formed between two of the first outer circumferential fins that are adjacent in the circumferential direction, the second outer circumferential fin has a second opposing end (122) that is the end on the first surface end side, and the second opposing end is located in a position aligned with the first opposing opening in the axial direction.

11. A drive device as described in any one of claims 1 to 3, wherein the heat generating portion has a surface mounting part (175) arranged in a plurality of rows in the circumferential direction along the inner circumferential surface (913) of the housing and provided on the inner circumferential surface of the housing, the first outer peripheral fin extends from a position aligned radially on the surface mounting part toward the first surface end, and the second outer peripheral fin extends from a position aligned radially on the surface mounting part toward the second surface end.

12. A drive device as described in any one of claims 1 to 3, 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.

13. The drive device according to any one of claims 1 to 3, which is a rotating electric machine provided in an aircraft (10) and drives the aircraft to fly.

Images