Electric propulsion unit

Abstract

To provide an electric propulsion unit which suppresses lowering of a degree of design freedom while achieving redundancy.SOLUTION: An electric propulsion unit includes a motor device, a first inverter device 80A, a second inverter device 80B, an output bus bar 93A (first bus bar), and an output bus bar 93B (second bus bar). The first inverter device 80A and the second inverter device 80B are arranged side by side along an inverter axis Ci. A first wiring board possessed by the first inverter device 80A and a second wiring board possessed by the second inverter device 80B are arranged in a direction vertical to the inverter axis Ci. The first inverter device 80A is arranged on a side closer to the motor device than the second inverter device 80B. Through holes 813d and 821d where the second bus bar is arranged are formed on the first wiring board.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The disclosure herein relates to an electric propulsion unit that rotates and drives a propeller on an aircraft. [Background technology]

[0002] Patent Document 1 describes an electric propulsion unit that electrically drives and rotates an aircraft propeller. This unit includes an inverter device that converts DC power supplied from a battery into AC power, and a motor device that drives and rotates the propeller with the power supplied from the inverter device. The inverter device and motor device are provided integrally to form an electrically and mechanically integrated electric propulsion unit. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] French Patent Invention No. 3089716 Summary of the Invention [Problem to be solved by the invention]

[0004] The inventors considered providing multiple inverter devices for one motor device to provide redundancy in the power supply to the motor device. However, they discovered that in this case, the placement of the bus bar that supplies power from the inverter devices to the motor device becomes a problem. For example, if a first inverter device is placed next to the motor device and a second inverter device is placed next to the first inverter, the bus bar that supplies power from the second inverter to the motor device must be placed to bypass the first inverter. This significantly limits the design freedom, such as the connection positions of the bus bars to the motor device and inverter devices, and the placement of the bus bars.

[0005] One disclosed object is to provide an electric propulsion unit that achieves redundancy while minimizing a reduction in design freedom. [Means for solving the problem]

[0006] In order to achieve the above object, an electric propulsion unit according to one aspect of the present disclosure comprises: a motor device (60) that rotates and drives a propeller (20) of an aircraft (10); a first inverter device (80A) having a first wiring board (813A, 821A, 822A) for converting DC power supplied from a battery (31) into AC power and supplying the AC power to a motor device; a second inverter device (80B) having second wiring boards (813B, 821B, 822B) for converting DC power supplied from the battery (31) into AC power and supplying the AC power to the motor device; a first bus bar (93A) that forms a power supply path from the first inverter device to the motor device; a second bus bar (93B) that forms a power supply path from the second inverter device to the motor device; the first inverter device and the second inverter device are arranged side by side along the rotation axis (Cm) of the motor device; the first wiring board and the second wiring board are arranged perpendicular to the rotation axis; the first inverter device is disposed closer to the motor device than the second inverter device; The first wiring board is formed with through holes (813d, 821d, 813s, 813c, 821c) in which the second bus bars are disposed.

[0007] When multiple inverter devices are arranged side by side along the rotation axis, the second bus bar connecting the second inverter device farther from the motor device to the motor device straddles the first inverter device closer to the motor device. Therefore, how to route the second bus bar within the first inverter device becomes an issue. To address this issue, the disclosed electric propulsion unit has a through hole formed in the first wiring board for passing the second bus bar. This prevents the second bus bar from having to detour around the outside of the first wiring board, simplifying the routing layout of the second bus bar. In other words, it is possible to provide redundancy by providing two inverter devices while minimizing a reduction in design flexibility.

[0008] The reference numbers in parentheses above merely indicate an example of the correspondence with specific configurations in the embodiments described below, and do not in any way limit the technical scope. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a diagram showing the configuration of an eVTOL to which an electric propulsion unit according to a first embodiment is applied. [Figure 2] 1 is a vertical cross-sectional view showing the layout of a motor device and an inverter device according to a first embodiment. [Figure 3] FIG. 2 is an electrical block diagram of the electric propulsion unit according to the first embodiment. [Figure 4] 1 is a vertical cross-sectional view of an inverter device according to a first embodiment. [Figure 5] FIG. 2 is a cross-sectional view of the first inverter device according to the first embodiment, as viewed from the motor side. [Figure 6] FIG. 11 is a cross-sectional view of a high-voltage board of a first inverter device according to a second embodiment, viewed from the motor side. [Figure 7] FIG. 11 is a cross-sectional view of a first inverter device according to a third embodiment, as viewed from the motor side. DETAILED DESCRIPTION OF THE INVENTION

[0010] 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.

[0011] (First embodiment) The propulsion system 30 shown in FIG. 1 is mounted on the eVTOL 10. The eVTOL 10 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 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 may be either a manned air vehicle with a crew member on board or an unmanned air vehicle without a crew member on board. The eVTOL 10 is operated by a pilot as a pilot. The pilot may operate the eVTOL 10 as a crew member, or may remotely operate the eVTOL 10 without being on board the eVTOL 10. The propulsion system 30 is a system that drives the eVTOL 10 to fly.

[0012] 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, in the front-to-rear direction. The airframe main body 12 has a passenger compartment for passengers. 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, etc.

[0013] 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 four 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.

[0014] The propeller 20 has blades 21. A plurality of the blades 21 are arranged in the circumferential direction of the propeller axis. In the propeller 20, the plurality of blades 21 are connected by a boss. In the propeller 20, a propeller shaft extends from the boss along the propeller axis. The propeller 20 is a variable-pitch propeller. In the propeller 20, the angle of the blades 21 with respect to the propeller axis can be changed.

[0015] Flight modes of the eVTOL 10 include vertical takeoff, vertical landing, cruising, hovering, etc. The eVTOL 10 can take off from a takeoff point by ascending vertically without running a taxiway, for example, as a vertical takeoff. The eVTOL 10 can land at a landing point by descending vertically, for example, as a vertical landing, without running a taxiway.

[0016] The eVTOL 10 is a tilt rotor aircraft. In the eVTOL 10, the tilt angle of the propeller 20 is adjustable. In the tilt rotor aircraft, one propeller 20 can function as both a lift propeller and a cruise propeller. Note that the multiple propellers 20 may include a lift propeller and a cruise propeller.

[0017] The eVTOL 10 has a battery 31, a distributor 32, an FCU 40, and an EPU 50. The battery 31, the distributor 32, the FCU 40, and the EPU 50 are included in the propulsion system 30. The battery 31 is connected to the multiple EPUs 50 so that electricity can be passed therethrough. The battery 31 is a DC voltage source that applies a DC voltage to the EPUs 50. The battery 31 has a secondary battery that can be charged and discharged. The battery 31 also supplies power to the FCU 40.

[0018] The distributor 32 is electrically connected to the battery 31 and the plurality of EPUs 50. The distributor 32 distributes the power from the battery 31 to the plurality of EPUs 50. The power distributed by the distributor 32 to the EPUs 50 is drive power for driving the EPUs 50.

[0019] The FCU 40 is a flight control device that controls the propulsion system 30. FCU is an abbreviation for Flight Control Unit. The FCU 40 performs flight control for flying the eVTOL 10. The FCU 40 is communicably connected to multiple EPUs 50. The FCU 40 controls the multiple EPUs 50 individually.

[0020] The EPU 50 is a device that drives the propellers 20 to rotate, and corresponds to an electric propulsion unit. EPU is an abbreviation for Electric Propulsion Unit. 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.

[0021] The propeller 20 rotates as the EPU 50 is driven. The eVTOL 10 flies due to the rotation of the propeller 20. In other words, the eVTOL 10 moves due to the rotation of the propeller 20. The eVTOL 10 has a propulsion device 15. The propulsion device 15 has the propeller 20 and the EPU 50. The propulsion device 15 propels the eVTOL 10 due to the rotation of the propeller 20. The propulsion device 15 is a device in which the propeller 20 and the EPU 50 are integrated. Note that, of the propeller 20 and the EPU 50, only the EPU 50 may be referred to as the propulsion device.

[0022] In the propulsion device 15, a propeller wind Wp (see FIG. 2) is generated as the propeller 20 rotates. The propeller wind Wp is a flow of gas such as air flowing in the axial direction AD. The propeller wind Wp flows from the propeller 20 toward the EPU 50. The EPU 50 is provided on the leeward side of the propeller wind Wp relative to the propeller 20. In this embodiment, the upwind side of the propeller wind Wp may be referred to as the upstream side, and the leeward side of the propeller wind Wp may be referred to as the downstream side. The propeller wind Wp is included in the flight wind generated as the eVTOL 10 flies.

[0023] The EPU 50 includes a motor unit 60, an inverter unit 80, an upstream fan 111, an EPU duct 120, a gear unit 100, and a pitch device 150. The motor unit 60 drives the propeller 20 to rotate. The inverter unit 80 converts DC power supplied from the battery 31 into AC power and supplies it to the motor unit 60. The motor unit 60 and the inverter unit 80 are configured as an integrated unit, making the EPU 50 an electro-mechanical integrated unit. The motor unit 60 and the inverter unit 80 generate heat when current is applied. An air-cooling system that uses outside air for cooling is used as a cooling system to suppress temperature increases due to this heat generation.

[0024] 2, the inverter device 80 according to this embodiment includes a first inverter device 80A and a second inverter device 80B. In this way, by providing a plurality of inverter devices for one motor device 60, redundancy is provided in the power supply to the motor device 60.

[0025] The motor device 60 and the inverter device 80 are formed as a whole in the shape of a short cylinder and extend in the axial direction AD. The motor device 60 and the inverter device 80 are aligned in the axial direction AD. The motor device 60 and the inverter device 80 are stacked in the axial direction AD. The motor device 60 and the inverter device 80 are provided coaxially. The inverter axis Ci (see FIG. 4), which is the center line of the inverter device 80, coincides with the motor axis Cm (see FIG. 3). The motor device 60 is provided between the inverter device 80 and the propeller 20 in the axial direction AD. The first inverter device 80A and the second inverter device 80B are aligned in the axial direction AD. The first inverter device 80A is arranged closer to the motor device 60 than the second inverter device 80B.

[0026] The motor device 60 has a motor 61 and a motor case 70. The motor case 70 is a housing that houses the motor 61. The motor 61 is a multi-phase AC motor. The motor 61 has a stator 62, rotors 64a and 64b, and a motor shaft 130. The motor 61 is configured to include mechanical parts such as the stator 62, rotors 64a and 64b, and motor shaft 130.

[0027] The stator 62 is a fixed element and is fixed to the motor case 70. The stator 62 has motor coils that form armature elements. The motor coils are multi-phase coils. The motor coils have multiple individual coils. The individual coils are multi-phase coils. The individual coils are n-phase coils. n is a natural number. The motor coils have m individual coils. m is a natural number. The motor coils have m individual coils of n phases, and are m×n-phase coils. When power is supplied to the m individual coils, the motor 61 operates as an m×n-phase motor. The motor 61 can be operated by supplying power to at least one individual coil. For example, when power is supplied to one individual coil, the motor 61 operates as a 1×n-phase motor.

[0028] In this embodiment, the motor coil has two individual coils. Each of the two individual coils is a three-phase coil. Therefore, the motor coil is a six-phase coil, and the motor 61 is a six-phase motor. When power is supplied to only one coil, the motor coil becomes a three-phase coil, and the motor 61 becomes a three-phase motor.

[0029] 3, the motor coil has two individual coils, a first coil 63a and a second coil 63b. The first coil 63a and the second coil 63b are each a three-phase coil. In the motor coil, the first coil 63a and the second coil 63b are arranged in the circumferential direction of rotation of the motor 61. For example, a plurality of coil portions forming the first coil 63a and a plurality of coil portions forming the second coil 63b are arranged alternately in the circumferential direction.

[0030] The rotors 64a, 64a are rotors that rotate relative to the stator 62. The motor shaft 130 is rotatably supported by a bearing 66 fixed to the motor case 70, and rotates together with the rotors 64a, 64b. The motor 61 is an axial gap motor. In the motor 61, the stator 62 and the rotors 64a, 64b are aligned in the axial direction AD. The motor 61 is also a double-rotor motor. In the motor 61, the first rotor 64a and the second rotor 64b are aligned in the axial direction AD with the stator 62 interposed therebetween.

[0031] The axial direction AD is the direction in which the motor axis Cm extends. The motor axis Cm is the rotation axis of the rotors 64a, 64b. The rotors 64a, 64b rotate around the motor axis Cm. The outside of the radial direction RD, which is perpendicular to the axial direction AD, is sometimes referred to as the radial outside or outer circumferential side. The inside of the radial direction RD is sometimes referred to as the radial inside or inner circumferential side.

[0032] The motor case 70 has a motor outer peripheral wall 71 and a motor facing wall 73. The motor outer peripheral wall 71 and the motor facing wall 73 are formed of a metal material or the like and have thermal conductivity. The motor outer peripheral wall 71 extends annularly in the circumferential direction CD. The motor outer peripheral wall 71 forms the outer peripheral surface of the motor case 70. The motor outer peripheral wall 71 covers the stator 62 and the rotors 64a, 64b from the outer periphery. A pair of motor facing walls 73 are arranged in the axial direction AD. The pair of motor facing walls 73 face each other with the stator 62, the rotors 64a, 64b, and the motor outer peripheral wall 71 between them. The motor facing walls 73 extend in a direction perpendicular to the axial direction AD. The motor facing walls 73 are fixed to the motor outer peripheral wall 71.

[0033] The motor case 70 has motor fins (not shown). The motor fins are provided on the motor outer peripheral wall 71. The motor fins dissipate heat from the motor case 70 to the outside of the motor device 60. The motor fins are heat dissipation fins that extend outward from the motor outer peripheral wall 71. The motor fins are plate-shaped and extend in the radial direction RD and the axial direction AD. Multiple motor fins are arranged in the circumferential direction CD.

[0034] The inverter device 80 has an inverter 81, an inverter control unit 82, and an inverter case 83. The inverter case 83 is a housing that houses the inverter 81 and the inverter control unit 82. The inverter 81 is configured to include multiple electronic components such as switching elements and capacitor elements, and a high-voltage (e.g., 400 V) wiring board. The inverter control unit 82 is configured to include multiple electronic components such as a processor and memory, and a low-voltage (e.g., 15 V) wiring board.

[0035] The inverter 81, inverter control unit 82, and inverter case 83 are provided in each of the first inverter device 80A and the second inverter device 80B. In the following description, the inverter 81, inverter control unit 82, and inverter case 83 provided in the first inverter device 80A will be referred to as the first inverter 81A, first inverter control unit 82A, and first inverter case 83A, respectively. The inverter 81, inverter control unit 82, and inverter case 83 provided in the second inverter device 80B will be referred to as the second inverter 81B, second inverter control unit 82A, and second inverter case 83B, respectively.

[0036] 3, the motor device 60 is illustrated as eMOT, the first coil 63a as CL1, the second coil 63b as CL2, the first rotor 64a as Rot1, and the second rotor 64b as Rot2. The first inverter device 80A is illustrated as MCU1, the first inverter 81A as INV1, and the first inverter control unit 82A as ICD1. The second inverter device 80B is illustrated as MCU2, the second inverter 81B as INV2, and the second inverter control unit 82B as ICD2. MCU is an abbreviation for Motor Control Unit.

[0037] The first inverter 81A converts DC power supplied from the battery 31 into AC power and supplies it to the first coil 63a. The second inverter 81B converts DC power supplied from the battery 31 into AC power and supplies it to the second coil 63b. The first inverter control unit 82A controls the operation of the first inverter 81A based on commands from the FCU 40. The second inverter control unit 82B controls the operation of the second inverter 81B based on commands from the FCU 40.

[0038] In the EPU 50, when both the first inverter control unit 82A and the second inverter control unit 82B perform motor control, the motor 61 is driven in six phases. In six phase drive, the motor 61 is driven as a six-phase motor. In the EPU 50, when only one of the first inverter control unit 82A and the second inverter control unit 82B performs motor control, the motor 61 is driven in three phases. In three phase drive, the motor 61 is driven as a three-phase motor. The FCU 40 can switch between six phase drive and three phase drive of the motor 61 by controlling the inverter control units 82A and 82B. In short, each of the two inverter control units can independently control the motor 61.

[0039] Next, the structures of the inverter case 83 and the motor case 70 will be described with reference to Figure 2. The inverter case 83 has an inverter inner hole 83c. The inverter inner hole 83c penetrates the inverter case 83 in the axial direction AD. The inverter inner hole 83c extends in the axial direction AD along the motor axis Cm. The inverter inner hole 83c is provided in the center of the inverter case 83. The center line of the inverter inner hole 83c coincides with the motor axis Cm.

[0040] The inverter case 83 has an inverter outer peripheral wall 831, an inverter inner peripheral wall 832, and an inverter facing wall 833. The inverter outer peripheral wall 831, the inverter inner peripheral wall 832, and the inverter facing wall 833 are formed of a metal material or the like and have thermal conductivity.

[0041] The inverter outer peripheral wall 831 and the inverter inner peripheral wall 832 extend annularly in the circumferential direction CD. The inverter outer peripheral wall 831 forms the outer peripheral surface of the inverter case 83. The inverter inner peripheral wall 832 forms the inner circumferential surface of the inverter case 83. The inverter inner peripheral wall 832 forms an inverter inner peripheral hole 83c. The inverter outer peripheral wall 831 and the inverter inner peripheral wall 832 are aligned in the radial direction RD and face each other with the inverter 81 and the inverter control unit 82 interposed therebetween.

[0042] The inverter facing walls 833 are arranged in a pair in the axial direction AD. The pair of inverter facing walls 833 face each other across the inverter 81, the inverter control unit 82, the inverter outer peripheral wall 831, and the inverter inner peripheral wall 832. The inverter facing walls 833 extend in a direction perpendicular to the axial direction AD. The inverter facing walls 833 are fixed to the inverter outer peripheral wall 831 and the inverter inner peripheral wall 832.

[0043] The inverter case 83 has inverter fins 83f shown in Fig. 4. The inverter fins 83f are provided on the inverter outer peripheral wall 831. The inverter fins 83f dissipate heat from the inverter case 83 to the outside of the inverter device 80. The inverter fins 83f are heat dissipation fins extending from the inverter outer peripheral wall 831 toward the outer periphery. The inverter fins 83f have a plate shape extending in the radial direction RD and also in the axial direction AD. A plurality of inverter fins 83f are arranged in the circumferential direction CD.

[0044] The motor case 70 and the inverter case 83 are aligned in the axial direction AD. For example, the motor outer peripheral wall 71 and the inverter outer peripheral wall 831 are aligned in the axial direction AD. The motor case 70 and the inverter case 83 are provided at positions separated from each other in the axial direction AD. The motor case 70 and the inverter case 83 are fixed together by fasteners such as bolts via spacers, for example.

[0045] The EPU 50 has a gear device 100. The gear device 100 mechanically connects the motor device 60 and the propeller 20. The gear device 100 transmits the drive of the motor device 60 to the propeller 20. The gear device 100 can change the rotation speed of the rotors 64a, 64b and the motor shaft 130 and output the rotation speed to the propeller 20. The gear device 100 is connected to the motor shaft 130.

[0046] The gear device 100 is provided between the motor device 60 and the propeller 20 in the axial direction AD. The gear device 100 is formed in the shape of a short cylinder as a whole, and extends in the axial direction AD. The gear device 100 is arranged next to the motor device 60 and the inverter device 80 in the axial direction AD. The gear device 100 is provided between the motor device 60 and the inverter device 80 and the propeller 20 in the axial direction AD. The gear device 100 is provided coaxially with the motor device 60 and the inverter device 80. The center line of the gear device 100 coincides with the motor axis line Cm.

[0047] The gear device 100 includes a gear, a gear shaft, and a gear housing. The gear shaft extends in an axial direction AD and connects the motor shaft 130 and the propeller 20. The gear includes a reducer and is provided on the gear shaft. The gear housing accommodates the gear.

[0048] The gear device 100 is arranged next to the motor case 70 and the inverter case 83 in the axial direction AD. The gear device 100 is provided at a position adjacent to the motor case 70, either the motor case 70 or the inverter case 83. The gear device 100 and the motor case 70 are provided at positions spaced apart in the axial direction AD.

[0049] The motor shaft 130 is connected to the gear device 100. The motor shaft 130 extends from the motor case 70 toward the gear device 100 in the axial direction AD. The motor shaft 130 is provided so as to penetrate the motor case 70 in the axial direction AD. The motor shaft 130 protrudes from the motor case 70 toward the inverter case 83. The motor shaft 130 is aligned with the inverter inner peripheral hole 83c in the axial direction AD. The motor shaft 130 is provided at a position spaced apart from the inverter inner peripheral hole 83c in the axial direction AD.

[0050] The motor shaft 130 has a hollow structure. The motor shaft 130 is formed into a cylindrical shape as a whole. The motor shaft 130 has a shaft space 140. The shaft space 140 is the internal space of the motor shaft 130. The hollow structure of the motor shaft 130 is realized by the shaft space 140. The shaft space 140 extends in the axial direction AD along the motor axis line Cm. The center line of the shaft space 140 coincides with the motor axis line Cm. The shaft space 140 is sometimes referred to as a hollow portion, and the motor shaft 130 is sometimes referred to as a hollow shaft.

[0051] The propulsion device 15 has a pitch device 150. The pitch device 150 can change the pitch of the propeller 20. For example, the pitch device 150 changes the pitch of the propeller 20 by changing the angle of the blades 21 with respect to the propeller axis. The pitch device 150 has a pitch controller 151, a pitch rod 152, and a pitch housing 153. The pitch controller 151 is configured to include an actuator such as a motor. The pitch rod 152 connects the pitch controller 151 and the propeller 20. The pitch controller 151 changes the pitch of the propeller 20 via the pitch rod 152. The pitch housing 153 accommodates the pitch controller 151. The pitch controller 151 and the pitch housing 153 are provided at positions downstream and away from the motor shaft 130 and the inverter case 83.

[0052] The pitch rod 152 is suspended between the pitch controller 151 and the propeller 20 via the motor shaft 130 and the gear device 100. The pitch rod 152 passes through the motor shaft 130 and extends in the axial direction AD.

[0053] The motor shaft 130 has a shaft flow passage 141. The shaft flow passage 141 is provided inside the motor shaft 130 and is a flow passage through which gas flows. The shaft flow passage 141 is a path through which the gas passes. The shaft flow passage 141 is formed to include at least a portion of the shaft space 140.

[0054] <Air cooling channel> The EPU 50 has an EPU duct 120. The EPU duct 120 houses the motor unit 60 and the inverter unit 80. The EPU duct 120 has thermal conductivity and is made of a metal material or a resin material. The EPU duct 120 covers the motor unit 60 and the inverter unit 80 from the outside. The EPU duct 120 covers at least a portion of the motor case 70 from the outside. The EPU duct 120 covers at least a portion of the inverter case 83 from the outside. The EPU duct 120 has a duct space 125. The duct space 125 is the internal space of the EPU duct 120.

[0055] The EPU 50 has an upstream fan 111. The upstream fan 111 is housed in an EPU duct 120. The upstream fan 111 is a blower fan such as a centrifugal fan. The upstream fan 111 is fixed to a motor shaft 130. The upstream fan 111 rotates together with the motor shaft 130 as the motor 61 is driven.

[0056] The upstream fan 111 blows air so that the gas passes through the duct space 125. When the upstream fan 111 rotates, the gas flows through the duct space 125 as shown by the arrows in FIG. 2. Specifically, outside air flows from the pitch space 155 into one side of the duct space 125 and flows out from the other side of the duct space 125. As a result, heat generated by the motor device 60 and the inverter device 80 is released to the outside of the EPU duct 120 together with the gas passing through the duct space 125.

[0057] Furthermore, the upstream fan 111 blows air in the duct space 125 so that the gas passes through the shaft flow path 141. In this case, heat imparted to the motor shaft 130 from the rotors 64a, 64b and the stator 62 is released to the outside of the motor shaft 130 together with the gas passing through the shaft flow path 141.

[0058] A duct backflow Fa1 occurs in the duct space 125. The duct backflow Fa1 flows in the axial direction AD, opposite to the propeller wind Wp. Specifically, as shown by the arrows in FIG. 2 , a portion of the outside air that flows from the pitch space 155 into the duct space 125 flows from the inside to the outside in the radial direction along the inverter facing wall 833. The air then flows in the axial direction AD through the outer peripheral flow passage 125a formed between the EPU duct 120 and the inverter outer peripheral wall 831, exchanging heat with the inverter fins 83f. Furthermore, a portion of the outside air that flows into the duct space 125 flows in the axial direction AD through the inverter inner peripheral hole 83c and then flows from the inside to the outside in the radial direction through the duct intermediate passage 125d. In short, the inverter case 83 is air-cooled at each of the inverter facing wall 833, the inverter inner peripheral wall 832, and the inverter outer peripheral wall 831.

[0059] A shaft reverse flow Fb1 occurs in the shaft flow passage 141. The shaft reverse flow Fb1 flows in the axial direction AD, opposite to the propeller wind Wp. The shaft reverse flow Fb1 flows in the same direction as the duct reverse flow Fa1. For example, the shaft reverse flow Fb1 flows in the axial direction AD through the shaft flow passage 141, penetrating at least the motor case 70. The upstream fan 111 blows air so that the shaft reverse flow Fb1 passes through the shaft flow passage 141. The outside air that flows into the shaft flow passage 141 from the inverter inner peripheral hole 83c cools the motor shaft 130 and the bearing 66. The outside air also flows in the axial direction AD through the outer peripheral flow passage 125a formed between the EPU duct 120 and the motor outer peripheral wall 71, exchanging heat with the motor fins. The motor case 70 is also air-cooled by the outside air flowing through the duct intermediate passage 125d.

[0060] In other words, a gap that functions as a flow path for cooling air is formed between the motor case 70 and the inverter case 83, and this gap functions as the aforementioned duct intermediate path 125d. The inverter inner peripheral hole 83c corresponds to a through flow path that penetrates the inverter case 83 along the inverter axis Ci. The duct intermediate path 125d (gap) also functions as a communication path that connects the through flow path and the outer peripheral flow path 125a.

[0061] <Busbar Overview> As shown in FIG. 2, a power connector 160 is provided on the outside of the inverter case 83, and is connected to a harness (not shown) of the battery 31. P bus bars 91A, 91B and N bus bars 92A, 92B are connected to the power connector 160. The P bus bar 91A connects the high potential side of the battery 31 to the first inverter device 80A. The P bus bar 91B connects the high potential side of the battery 31 to the second inverter device 80B. The N bus bar 92A connects the low potential side of the battery 31 to the first inverter device 80A. The N bus bar 92B connects the low potential side of the battery 31 to the second inverter device 80B. DC power is supplied from the battery 31 to the inverter device 80 via the P bus bars 91A, 91B and the N bus bars 92A, 92B.

[0062] The inverter device 80 and the motor device 60 are connected by an output bus bar 93B. The output bus bar 93A connects the first coil 63a and the first inverter device 80A. An output bus bar 93A is provided for each of the three phases of the first coil 63a. The output bus bar 93B connects the second coil 63b and the second inverter device 80B. An output bus bar 93B is provided for each of the three phases of the second coil 63b. AC power is supplied from the inverter device 80 to the motor device 60 by the output bus bars 93A and 93B provided for each of the six phases.

[0063] The P bus bar 91A and the N bus bar 92A correspond to first DC bus bars that form a power supply path from the battery 31 to the first inverter device 80A. The P bus bar 91B and the N bus bar 92B correspond to second DC bus bars that form a power supply path from the battery 31 to the second inverter device 80B. The output bus bar 93A corresponds to the first bus bar that forms a power supply path from the first inverter device 80A to the first coil 63a. The output bus bar 93B corresponds to the second bus bar that forms a power supply path from the second inverter device 80B to the second coil 63b.

[0064] <Inverter> As shown in Fig. 4, inverter 81 has a plurality of electronic components and high-voltage boards 813A and 813B. The plurality of electronic components include a plurality of switching elements 811A and 811B and capacitor elements 812A and 812B. High-voltage boards 813A and 813B are wiring boards for a high voltage system (e.g., 400V). In this specification, a configuration with a reference numeral ending in A indicates a configuration included in first inverter device 80A. A configuration with a reference numeral ending in B indicates a configuration included in second inverter device 80B.

[0065] The output terminals of the switching elements 811A and 811B are connected to the output bus bars 93A and 93B via high-voltage wiring provided on the high-voltage boards 813A and 813B. The switching elements 811A and 811B form upper and lower arm circuits. The switching elements 811A and 811B are thermally connected to the inverter outer peripheral wall 831.

[0066] Capacitor elements 812A and 812B are mounted on the motor-side surfaces of high-voltage boards 813A and 813B. Capacitor elements 812A and 812B are connected to the input terminals of switching elements 811A and 811B, P bus bars 91A and 91B, and N bus bars 92A and 92B via the high-voltage wiring. Capacitor elements 812A and 812B function as smoothing capacitors that reduce pulsation in the voltage applied to switching elements 811A and 811B.

[0067] The high-voltage boards 813A, 813B are arranged in a direction perpendicular to the motor axis Cm. A through-hole 813c is formed in the center of the high-voltage boards 813A, 813B. The high-voltage boards 813A, 813B have a shape that extends in an annular shape centered on the inverter axis Ci. The high-voltage boards 813A, 813B are provided with a terminal block 813g that is connected to the output bus bars 93A, 93B. The high-voltage boards 813A, 813B are provided with a terminal block 813h (see Figure 5) that is connected to the P bus bars 91A, 91B and the N bus bars 92A, 92B. These terminal blocks 813g, 813h are structured to be connected to the bus bars with fastening members such as bolts and screws.

[0068] <Inverter control unit> 4, inverter control unit 82 has multiple electronic components, drive boards 821A and 821B, and control boards 822A and 822B. The multiple electronic components include gate resistor elements mounted on drive boards 821A and 821B, and microcomputers mounted on control boards 822A and 822B. Drive boards 821A and 821B are wiring boards that output switch on / off signals to signal terminals of switching elements 811A and 811B. Control boards 822A and 822B control the operation of inverter 81 by controlling the operation of drive boards 821A and 821B based on commands from FCU 40.

[0069] The drive boards 821A, 821B and the control boards 822A, 822B are arranged in a direction perpendicular to the motor axis Cm. Through holes 821c, 822c are formed in the centers of the drive boards 821A, 821B and the control boards 822A, 822B. The drive boards 821A, 821B and the control boards 822A, 822B are shaped to extend in an annular shape centered on the inverter axis Ci. The drive boards 821A, 821B are arranged between the control boards 822A, 822B and the high-voltage boards 813A, 813B.

[0070] Drive boards 821A, 821B and control boards 822A, 822B are low-voltage (e.g., 15V) wiring boards. That is, high-voltage circuits are concentrated on high-voltage boards 813A, 813B, and low-voltage circuits are concentrated on drive boards 821A, 821B and control boards 822A, 822B. Low-voltage power supplied to inverter device 80 is supplied to drive boards 821A, 821B and control boards 822A, 822B via a low-voltage bus bar (not shown).

[0071] The high-voltage board 813A, the drive board 821A, and the control board 822A correspond to the first wiring board of the first inverter device 80A. The first wiring board converts DC power supplied from the battery 31 into AC power and supplies it to the first coil 63a. The high-voltage board 813B, the drive board 821B, and the control board 822B correspond to the second wiring board of the second inverter device 80B. The second wiring board converts DC power supplied from the battery 31 into AC power and supplies it to the second coil 63b.

[0072] <Inverter case> As shown in FIG. 4, the inverter case 83 is divided into a first inverter case 83A that houses a first wiring board and a second inverter case 83B that houses a second wiring board. The inverter outer peripheral wall 831 and the inverter inner peripheral wall 832 described above with reference to FIG. 2 are included in the first inverter case 83A and the second inverter case 83B. The inverter outer peripheral wall 831 and the inverter inner peripheral wall 832 have a cylindrical shape that extends in the axial direction AD around the inverter axis Ci. The inverter outer peripheral wall 831 and the inverter inner peripheral wall 832 are connected by a plurality of beam members 834. The beam members 834 have a shape that extends radially in the radial direction around the inverter axis Ci.

[0073] Beam member 834 is disposed between high-voltage boards 813A, 813B and drive boards 821A, 821B. High-voltage boards 813A, 813B and drive boards 821A, 821B are attached to and supported by beam member 834. Control boards 822A, 822B are attached to and supported by drive boards 821A, 821B.

[0074] An opening of inverter outer peripheral wall 831 of first inverter case 83A located on the opposite side to second inverter case 83B is closed by inverter facing wall 833. An opening of inverter outer peripheral wall 831 of second inverter case 83B located on the opposite side to first inverter case 83A is closed by inverter facing wall 833. In addition to functioning as a passage wall for cooling air in duct space 125, inverter facing wall 833 also functions as a cover for inverter outer peripheral wall 831.

[0075] The intermediate portion of the inverter outer peripheral wall 831 in the axial direction AD is partitioned by a partition plate 835. A through-hole 835c is formed in the center of the partition plate 835. The partition plate 835 is in the shape of a disk extending annularly about the inverter axis Ci. The through-holes 813c, 821c, and 822c of each substrate and the through-hole 835c of the partition plate 835 are positioned coaxially. These through-holes are formed to be the same size. Note that the beam member 834 and the partition plate 835 shown in FIG. 4 are omitted from FIG. 2.

[0076] The first inverter case 83A has one each of an inverter outer peripheral wall 831, an inverter inner peripheral wall 832, an inverter facing wall 833, and a partition plate 835. The second inverter case 83B has one each of an inverter outer peripheral wall 831, an inverter inner peripheral wall 832, and an inverter facing wall 833. Each of the first inverter case 83A and the second inverter case 83B has a plurality of beam members 834.

[0077] A plurality of brackets 836 are provided on the inverter outer peripheral wall 831. The brackets 836 are shaped to protrude in the radial direction RD. As shown in FIG. 5, a plurality of brackets 836 are arranged side by side in the circumferential direction CD. The brackets 836 of the first inverter case 83A and the brackets 836 of the second inverter case 83B are connected by fastening members such as bolts or screws. This joins the first inverter case 83A and the second inverter case 83B to each other. In other words, the first inverter case 83A and the second inverter case 83B are arranged side by side in the axial direction AD and adjacent to each other.

[0078] <Busbar arrangement> The inverter-facing wall 833 of the first inverter case 83A is formed with through-holes 833c penetrating in the axial direction AD. The output bus bars 93A, 93B are inserted into the through-holes 833c. The through-holes 833c may be formed in the inverter outer peripheral wall 831 of the first inverter case 83A. The output bus bars 93A, 93B have a solid cylindrical shape. The through-hole 833c is circular and conforms to the outer shapes of the output bus bars 93A, 93B. In this embodiment, there are three output bus bars 93A connected to the first inverter device 80A and three output bus bars 93B connected to the second inverter device 80B. Therefore, six through-holes 833c are formed.

[0079] The output bus bars 93A, 93B are arranged to cross the duct intermediate passage 125d (gap), and the portions of the output bus bars 93A, 93B located in the duct intermediate passage 125d are covered with an electrical insulator 94. The electrical insulator 94 is made of an electrically insulating resin and has a cylindrical shape that covers the electrical insulator 94. The electrical insulator 94 protects the output bus bars 93A, 93B from foreign matter such as moisture and dust contained in the outside air.

[0080] Through holes 813d, 821d, and 835d are formed in the high-voltage board 813A, drive board 821A, and partition plate 835 of the first inverter case 83A, respectively. The output bus bars 93A and 93B are inserted into the through holes 813d, 821d, and 835d. The through holes 813d, 821d, and 835d are circular and conform to the outer shape of the output bus bar 93B. In this embodiment, there are three output bus bars 93B connected to the second inverter device 80B. Therefore, three through holes 813d, 821d, and 835d are formed. The four through holes 833c, 813d, 821d, and 835d are formed at the same positions as seen from the axial direction AD and are aligned in a straight line in the axial direction AD. The beam members 834 of the first inverter case 83A are positioned so as not to interfere with the main body 931B (see FIG. 5). In other words, the main body portion 931B is disposed between a plurality of beam members 834.

[0081] The output bus bar 93B includes a main body 931B and an adjusting conductor 932B. The main body 931B has a shape that extends linearly in the axial direction AD. The main body 931B is inserted into four through holes 833c, 813d, 821d, and 835d. The adjusting conductor 932B is disposed inside the second inverter case 83B and has a portion that extends in the radial direction RD. One end of the adjusting conductor 932B is formed with a connection hole 93c into which the main body 931B is inserted. The main body 931B inserted into the connection hole 93c is connected to the adjusting conductor 932B by a fastening member such as a bolt or a screw.

[0082] The other end of the adjustment conductor 932B is connected to the terminal block 813g. One end of the output bus bar 93A is connected to the terminal block 813g. Fastening members such as bolts and screws are used to connect the bus bars to the terminal block 813g. The terminal block 813g of the first inverter device 80A and the terminal block 813g of the second inverter device 80B are located at the same position when viewed from the axial direction AD. In other words, the adjustment conductor 932B has a shape in which the output bus bar 93B is bent in the radial direction so that the radial position of the main body 931B is offset from the position of the terminal block 813g.

[0083] The connecting hole 93c is larger in the radial direction RD than the main body 931B. This allows the adjustment conductor 932B and the main body 931B to be connected with a fastening member after adjusting the relative radial positions of the adjustment conductor 932B and the main body 931B. In other words, the amount of offset described above can be adjusted by the radial dimension of the connecting hole 93c.

[0084] The P bus bars 91A, 91B and the N bus bars 92A, 92B are inserted into through holes 821c, 822c of the drive board 821B and the control board 822B of the second inverter device 80B and into through hole 813c of the high-voltage board 813B. The P bus bars 91A, 91B and the N bus bars 92A, 92B are arranged on the opposite side of the inverter inner peripheral wall 832 from the inverter inner peripheral hole 83c. As a result, the P bus bars 91A, 91B and the N bus bars 92A, 92B are isolated by the inverter inner peripheral wall 832 from the outside air flowing through the inverter inner peripheral hole 83c. The P bus bars 91A, 91B and the N bus bars 92A, 92B have a solid cylindrical shape and are arranged to extend axially along the inverter inner peripheral wall 832.

[0085] Furthermore, the P bus bar 91A and N bus bar 92A connected to the first inverter device 80A are inserted into the through holes 821c, 822c of the drive board 821A and control board 822A of the first inverter device 80A, and also into the through hole 813c of the high-voltage board 813A.

[0086] As described above, the high-voltage substrate 813B, drive substrate 821B, and control substrate 822B of the second inverter device 80B are also referred to as second wiring substrates. The P bus bar 91A and the N bus bar 92A connected to the first inverter device 80A are also referred to as first DC bus bars. The through holes 813c and 821c formed in the second wiring substrate correspond to DC through holes into which the first DC bus bars are inserted. The through holes 813d and 821d formed in the first wiring substrate correspond to AC through holes into which the output bus bar 93B connected to the second inverter device 80B is inserted. As shown in FIGS. 4 and 5, the DC through holes are formed closer to the inverter axis Ci (rotation axis) than the AC through holes.

[0087] Terminal blocks 813h (see FIG. 5) for connecting these PN bus bars are provided on the high-voltage boards 813A and 813B. Such terminal blocks 813 for the PN bus bars are not shown in FIG. 4. The terminal block 813h for the PN bus bars of the first inverter device 80A and the terminal block 813h for the PN bus bars of the second inverter device 80B are located at the same position when viewed from the axial direction AD.

[0088] As shown in FIG. 5, on the high-voltage board 813A of the first inverter device 80A, the terminal block 813g and the through-hole 813d are arranged to align on a straight line that intersects perpendicularly with the inverter axis Ci. In other words, the main body 931B of the output bus bar 93B (second bus bar) and the output bus bar 93A (first bus bar) are arranged to align on a straight line that intersects perpendicularly with the inverter axis Ci when viewed from the axial direction AD. Furthermore, the bracket 836 is located on this straight line. In other words, the main body 931B of the second bus bar and the first bus bar are located on an imaginary line L1 (see FIG. 5) that connects the bracket 836 and the inverter axis Ci and extends in the radial direction RD. Furthermore, on the high-voltage board 813A of the first inverter device 80A, the second bus bar is formed at a position closer to the inverter axis Ci (axis of rotation) than the first bus bar.

[0089] <Summary of the First Embodiment> According to the present embodiment described above, the first inverter device 80A and the second inverter device 80B are arranged side by side along the motor axis Cm. The first wiring board and the second wiring board are arranged perpendicular to the motor axis Cm. The first inverter device 80A is arranged closer to the motor device 60 than the second inverter device 80B. Through holes 813d, 821d in which the second bus bars are arranged are formed in the first wiring boards, i.e., the high-voltage board 813A and the drive board 821A of the first inverter device 80A.

[0090] When multiple inverter devices 80 are arranged side by side along the motor axis Cm, the second bus bar connecting the second inverter device 80B, which is farther from the motor device 60, to the motor device 60 crosses over the first inverter device 80A, which is closer. Therefore, how to route the second bus bar within the first inverter device 80A becomes an issue. To address this issue, in this embodiment, the first wiring board is provided with through-holes 813d and 821d for passing the second bus bar therethrough. This avoids having to route the second bus bar around the outer periphery of the first wiring board, simplifying the routing layout of the second bus bar.

[0091] Furthermore, in this embodiment, the first inverter device 80A has a first inverter case 83A that houses a first wiring board. The second inverter device 80B has a second inverter case 83B that houses a second wiring board. The first inverter case 83A and the second inverter case 83B are adjacent to each other. Specifically, the two cases are fastened together with a bracket 836 so that they are in contact with each other without any gaps.

[0092] In this manner, in the case of a layout in which both cases are adjacent to each other and aligned along the motor axis Cm, if the second bus bar is routed around the outer periphery of the first wiring board, contrary to the present embodiment, the structure becomes even more complicated and also increases in size in the radial direction. Therefore, in the case of EPU 50 in which both cases are adjacent to each other, the above-described effects of providing through holes 813d, 821d are significantly exhibited.

[0093] Here, inverter device 80 includes many components that generate heat when current is applied. In addition to switching elements, bus bars are also heat-generating components. Strictly speaking, the second bus bar generates more heat than the first bus bar because it is longer in the axial direction AD. However, the bus bar generates less heat than switching elements 811A and 811B. Furthermore, the amount of heat dissipated from the case is large at positions inside inverter case 83 that are close to the outer surface of the case. Therefore, it is desirable to position switching elements 811A and 811B near the outer surface of the case to efficiently dissipate heat. In this case, it is desirable to reduce the uneven temperature distribution within the case by positioning the second bus bar, which generates more heat than the first bus bar, at a distance from switching elements 811A and 811B.

[0094] In consideration of this point, in this embodiment, the second bus bar is arranged closer to the rotation axis than the first bus bar inside the first inverter device 80A, which reduces the unevenness of the temperature distribution inside the first inverter case 83A.

[0095] Furthermore, in this embodiment, the second bus bar includes an adjustment conductor 932B disposed inside the second inverter device 80B and having a portion extending perpendicular to the rotation axis. This allows the connection point of the first bus bar on the first wiring board to be closer to the connection point of the second bus bar on the second wiring board. This allows the first wiring board and the second wiring board to have similar component layouts and wiring layouts. In other words, the first inverter device 80A and the second inverter device 80B can share more parts. This improves the efficiency of the manufacturing process and component mounting process for the first wiring board and the second wiring board, thereby improving productivity.

[0096] Here, providing through-hole 813d in the first wiring substrate imposes design constraints on the wiring layout and the layout of mounted components on the first wiring substrate. Furthermore, if the space on the substrate for mounted components and wiring is wide in the circumferential direction, the dead space can be reduced. Therefore, if through-hole 813d is provided so that the first bus bar and the second bus bar are aligned in the circumferential direction, contrary to this embodiment, the dead space increases. In consideration of this, in this embodiment, through-hole 813d in which the second bus bar is arranged and the first bus bar are aligned on a straight line perpendicular to the rotation axis when viewed from the axial direction AD. Therefore, a wide space can be secured in the circumferential direction on the first wiring substrate for mounted components and wiring. This reduces the dead space on the first wiring substrate.

[0097] Here, the portion of the outer circumferential surface of the inverter case 83 where the bracket 836 is located has poor heat dissipation because inverter fins 83f cannot be provided. Therefore, it is desirable not to arrange the switching elements 811A, which generate a large amount of heat, on the imaginary line L1. In consideration of this, in this embodiment, the main body portion 931B of the second bus bar and the first bus bar are positioned on the imaginary line L1 that connects the bracket 836 and the inverter axis Ci and extends in the radial direction RD. Therefore, the space on the imaginary line L1, where it is not desirable to arrange the switching elements 811A, can be effectively utilized by arranging the bus bar.

[0098] Furthermore, in this embodiment, a gap is formed between the motor case 70 and the first inverter case 83A, and this gap functions as a duct intermediate path 125d, which is a flow path for cooling air. The first bus bar and the second bus bar are arranged to cross the duct intermediate path 125d. This allows both bus bars to be cooled by the cooling air, reducing the risk of damage to the first wiring board due to heat generated in the bus bars when current is applied.

[0099] Furthermore, in this embodiment, the portions of output bus bars 93A and 93B located in the gap are covered with electrical insulator 94. This protects output bus bars 93A and 93B from foreign matter such as moisture and dust contained in the cooling air.

[0100] Furthermore, in this embodiment, an inverter inner circumferential hole 83c (through-flow passage) is formed in the first inverter case 83A, penetrating along the rotation axis. The motor outer circumferential wall 71 of the motor case 70 functions as the wall surface of the outer circumferential passage 125a through which air flows in the direction of the rotation axis. The gap functions as a communication passage that connects the inverter inner circumferential hole 83c and the outer circumferential passage 125a. By using such a communication passage to cool the output bus bars 93A and 93B, the bus bars can be cooled efficiently.

[0101] Furthermore, in this embodiment, a P bus bar 91A and an N bus bar 92A (first DC bus bar) are provided to supply power from the battery 31 to the first inverter device 80A. A P bus bar 91B and an N bus bar 92B (second DC bus bar) are provided to supply power to the second inverter device 80B. DC through holes 813c and 821c are formed in the second wiring board, in which the first DC bus bars are disposed.

[0102] When multiple inverter devices 80 are arranged side by side along the motor axis Cm, the DC first bus bar connecting the first inverter device 80A closer to the motor device 60 and the motor device 60 crosses over the second inverter device 80B farther away. Therefore, how to route the DC first bus bar within the second inverter device 80B becomes an issue. To address this issue, in this embodiment, the second wiring board is provided with DC through-holes 813c and 821c through which the DC first bus bar passes. This avoids having to route the first bus bar around the outer periphery of the second wiring board, simplifying the routing layout of the first bus bar.

[0103] Furthermore, in this embodiment, the DC through holes 813c, 821c are formed at positions closer to the rotation axis than the AC through holes 813d, 821d. This makes it possible to reduce the unevenness of the temperature distribution inside the inverter case 83.

[0104] (Second embodiment) In this embodiment, as shown in Fig. 6, on the high-voltage board 813A of the first inverter device 80A, three terminal blocks 813g are arranged at equal intervals in the circumferential direction CD. Similarly, three through holes 813d are arranged at equal intervals in the circumferential direction CD. They are arranged side by side. In other words, as shown in Fig. 6, the three terminal blocks 813g and the through holes 813d are all spaced apart from each other by the same circumferential distance L2.

[0105] Other configurations of this embodiment are the same as those of the first embodiment. For example, the motor device 60 is a six-phase motor. The first inverter device 80A and the first bus bar supply power to three phases of the six-phase motor. The second inverter device 80B and the second bus bar supply power to the other three phases of the six-phase motor. Therefore, the number of second bus bars is three, and accordingly, the number of through holes 813d, 821d in which the second bus bars are arranged is also three.

[0106] As described above, according to this embodiment, the high-voltage substrate 813A has three through holes 813d formed at equal intervals around the rotation axis. Therefore, when arranging mounted components and laying out wiring on one high-voltage substrate 813A, the mounted components and wiring required for each phase can be laid out in an area divided into three equal parts in the circumferential direction. This makes it possible to reduce the wasted area on the high-voltage substrate 813A, and ultimately to reduce the size of the high-voltage substrate 813A. The same is true for the drive substrate 821A, where three through holes 821d are formed at equal intervals around the rotation axis. Therefore, when arranging mounted components and laying out wiring on one drive substrate 821A, the mounted components and wiring required for each phase can be laid out in an area divided into three equal parts in the circumferential direction. This makes it possible to reduce the wasted area on the drive substrate 821A, and ultimately to reduce the size of the drive substrate 821A.

[0107] (Third embodiment) In the first embodiment described above, the number of high-voltage substrates 813A is one. In contrast, in this embodiment, as shown in Fig. 7, the high-voltage substrate 813A is divided into multiple substrates. For example, if one inverter device supplies power to the motor device 60 for three phases, the high-voltage substrate 813A is divided into three. In other words, the high-voltage substrate 813A is divided into the same number of substrates as the number of phases it supplies.

[0108] Each of the divided high-voltage substrates 813A has the same shape and size and is arranged at equal intervals in the circumferential direction. This facilitates common use of the divided high-voltage substrates 813A, reducing manufacturing costs. Furthermore, for both the first inverter device 80A and the second inverter device 80B, the high-voltage substrates 813A, 813B may be divided into multiple substrates. In this case, it is desirable that the divided high-voltage substrates 813A, 813B in each of the first inverter device 80A and the second inverter device 80B have the same shape and size.

[0109] The divided high-voltage substrates 813A are arranged at predetermined intervals from one another. For example, the multiple high-voltage substrates 813A are arranged side by side in the circumferential direction CD with an interval therebetween. In the following description, the intervals are referred to as substrate gaps 813s. The output bus bar 93B (second bus bar) is arranged in this substrate gap 813s. For example, the main body portion 931B of the output bus bar 93B is inserted into each of the three substrate gaps 813s present in the circumferential direction. In short, the through hole 813d according to the first embodiment is replaced with the substrate gaps 813s in this embodiment, and the substrate gaps 813s correspond to the through holes.

[0110] 7, the terminal block 813g and the main body 931B are not arranged in a straight line on the imaginary line L1, but are arranged at different positions in the circumferential direction CD. However, the high-voltage circuit board 813A may be divided so that the board gap 813s is curved with respect to the imaginary line L1, and both the terminal block 813g and the main body 931B may be arranged on the imaginary line L1.

[0111] The drive substrate 821A may also be divided into multiple pieces, similar to the high-voltage substrate 813A. A second bus bar may be arranged between the multiple drive substrates 821A. In short, the through-hole 821d according to the first embodiment may be replaced with a substrate gap in the drive substrate 821A. Also, either the drive substrate 821A or the high-voltage substrate 813A may be divided and replaced with a substrate gap.

[0112] Each of the divided drive substrates 821A has the same shape and size and is arranged at equal intervals in the circumferential direction. This allows for commonality of the divided drive substrates 821A and reduces manufacturing costs. Furthermore, for both the first inverter device 80A and the second inverter device 80B, the drive substrates 821A and 821B may be divided into multiple substrates. In this case, it is desirable that the divided drive substrates 821A and 821B in each of the first inverter device 80A and the second inverter device 80B have the same shape and size.

[0113] (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 the omission of parts and elements from the embodiments. 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.

[0114] In the first embodiment, inverter case 83 has partition plate 835, and this partition plate 835 also has through holes 835d formed therein for inserting bus bars. However, partition plate 835 may have the same structure as beam member 834, and the spaces between the beams may function as through holes 835d. Alternatively, partition plate 835 may be eliminated.

[0115] In the first embodiment, by making the outer shape of control board 822A smaller than the outer shape of high-voltage board 813A, control board 822A does not need to have through holes for inserting output bus bars 93A and 93B. Alternatively, through holes for inserting bus bars may be formed in control board 822A. Furthermore, the outer shape of drive board 821A may be made small like control board 822A, and through hole 821d formed in drive board 821A may be eliminated.

[0116] The high-voltage substrate 813B of the second inverter device 80B may also have a through-hole 813d formed therein similar to that of the first inverter device 80A. The through-holes 813d formed in each of the two high-voltage substrates 813A, 813B have the same shape, position, and size. This facilitates standardization of the two high-voltage substrates 813A, 813B, thereby reducing manufacturing costs. Furthermore, the drive substrate 821B of the second inverter device 80B may also have a through-hole 821d formed therein similar to that of the first inverter device 80A. The through-holes 821d formed in each of the two drive substrates 821A, 821B have the same shape, position, and size. This facilitates standardization of the two drive substrates 821A, 821B, thereby reducing manufacturing costs.

[0117] In the first embodiment, the second bus bars are arranged in the through holes 813d and 821d. However, the through holes 813d and 821d may be eliminated, and the second bus bars may be arranged in the central DC through holes 813c and 821c.

[0118] In the first embodiment, DC through holes 813c and 821c are formed in the center of the first wiring substrate, and the first wiring substrate is formed in a ring shape. However, DC through holes 813c and 821c may be eliminated, and the first wiring substrate may be formed in a non-ring shape. In that case, inverter inner peripheral hole 83c would also be eliminated.

[0119] In the first embodiment, the portions of the output bus bars 93A and 93B exposed to the cooling air are protected by the electrical insulator 94. Similarly, the portions of the DC bus bars exposed to the cooling air may be protected by the electrical insulator.

[0120] In the first embodiment, the high-voltage substrate 813A and the drive substrate 821A are configured as separate substrates, but they may be configured as a single substrate. The drive substrate 821A and the control substrate 822A may also be configured as a single substrate. The high-voltage substrate 813A, the drive substrate 821A, and the control substrate 822A may also be configured as a single substrate.

[0121] (Disclosure of technical ideas) This specification discloses multiple technical ideas described in the following multiple clauses. Some clauses may be written in a multiple dependent form, with the subsequent clause referring to the preceding clause as an alternative. Furthermore, some clauses may be written in a multiple dependent form, referring to another multiple dependent clause. These multiple dependent clauses define multiple technical ideas.

[0122] (Technical thought 1) a motor device (60) that rotates and drives a propeller (20) of an aircraft (10); a first inverter device (80A) having a first wiring board (813A, 821A, 822A) that converts DC power supplied from the battery (31) into AC power and supplies the AC power to the motor device; a second inverter device (80B) having a second wiring board (813B, 821B, 822B) that converts DC power supplied from the battery (31) into AC power and supplies the AC power to the motor device; a first bus bar (93A) that forms a power supply path from the first inverter device to the motor device; a second bus bar (93B) that forms a power supply path from the second inverter device to the motor device, the first inverter device and the second inverter device are arranged side by side along a rotation axis (Cm) of the motor device, the first wiring board and the second wiring board are disposed in a direction perpendicular to the rotation axis, the first inverter device is disposed closer to the motor device than the second inverter device, The electric propulsion unit has through holes (813d, 821d, 813s, 813c, 821c) formed in the first wiring board, in which the second bus bars are arranged.

[0123] (Technical thought 2) the first inverter device has a first inverter case (83A) that houses the first wiring board, the second inverter device has a second inverter case (83B) that houses the second wiring board, The electric propulsion unit according to Technical Idea 1, wherein the first inverter case and the second inverter case are adjacent to each other.

[0124] (Technical Thought 3) The electric propulsion unit according to Technical Idea 1 or 2, wherein, inside the first inverter device, the second bus bar is arranged closer to the rotation axis than the first bus bar.

[0125] (Technical Thought 4) The electric propulsion unit described in Technical Idea 3, wherein the second bus bar includes an adjustment conductor (932B) arranged inside the second inverter device and having a portion extending in a direction perpendicular to the rotation axis.

[0126] (Technical Thought 5) The electric propulsion unit according to any one of Technical Ideas 1 to 4, wherein the first bus bar and the through hole are arranged to be aligned on a straight line that intersects perpendicularly with the rotation axis.

[0127] (Technical Thought 6) the motor device is a six-phase motor; the first inverter device and the first bus bar supply power to three phases of the six-phase motor; the second inverter device and the second bus bar supply power to three phases of the six-phase motor; The electric propulsion unit according to any one of Technical Ideas 1 to 5, wherein three of the through holes are formed in the first wiring board at equal intervals around the rotation axis.

[0128] (Technical Thought 7) The motor device includes a stator (62), rotors (64a, 64b), a motor shaft 130, and a motor case (70), the first inverter device has a first inverter case (83A) that houses the first wiring board, A gap (125d) is formed between the motor case and the first inverter case to function as a flow path for cooling air, The electric propulsion unit according to any one of Technical Concepts 1 to 6, wherein the first bus bar and the second bus bar are arranged to cross the gap.

[0129] (Technical Thought 8) The electric propulsion unit described in Technical Idea 7, wherein a portion of the first bus bar located in the gap and a portion of the second bus bar located in the gap are covered with an electrical insulator (94).

[0130] (Technical Thought 9) a through-flow passage (83c) is formed in the first inverter case and passes through the first inverter case along the rotation axis; The outer peripheral surface of the motor case functions as a wall surface of an outer peripheral flow path (125a) through which the fluid flows in the direction of the rotation axis, The electric propulsion unit according to Technical Idea 7 or 8, wherein the gap functions as a communication passage that connects the through passage and the outer peripheral passage.

[0131] (Technical Thought 10) a first DC bus bar (91A, 92A) that forms a power supply path from the battery to the first inverter device; a DC second bus bar (91B, 92B) that forms a power supply path from the battery to the second inverter device, The electric propulsion unit according to any one of Technical Ideas 1 to 9, wherein the second wiring board is formed with DC through holes (813c, 821c) in which the first DC bus bar is arranged.

[0132] (Technical Thought 11) The electric propulsion unit according to Technical Idea 10, wherein the DC through hole is formed at a position closer to the rotation axis than the through hole. [Explanation of symbols]

[0133] 10 eVTOL (aircraft) 125a outer peripheral flow path, 125d gap, 130 motor shaft, 20 propeller, 31 battery, 60 motor device, 62 stator, 64a, 64b rotor, 70 motor case, 80A first inverter device, 80B second inverter device, 813A first wiring board, 813B second wiring board, 813d, 821d, 813s, 813c, 821c through hole, 813c, 821c DC through hole, 821A first wiring board, 821B second wiring board, 822A first wiring board, 822B second wiring board, 83A first inverter case, 83B second inverter case, 83c through flow path, 91A first DC bus bar, 91B DC second bus bar, 92A DC first bus bar, 92B DC second bus bar, 932B adjusting conductor, 93A first bus bar, 93B second bus bar, 94 electrical insulator, Cm rotation axis.

Claims

1. a motor device (60) that rotates and drives a propeller (20) of an aircraft (10); a first inverter device (80A) having a first wiring board (813A, 821A, 822A) that converts DC power supplied from a battery (31) into AC power and supplies the AC power to the motor device; a second inverter device (80B) having a second wiring board (813B, 821B, 822B) that converts DC power supplied from the battery (31) into AC power and supplies the AC power to the motor device; a first bus bar (93A) that forms a power supply path from the first inverter device to the motor device; a second bus bar (93B) that forms a power supply path from the second inverter device to the motor device, the first inverter device and the second inverter device are arranged side by side along a rotation axis (Cm) of the motor device, the first wiring board and the second wiring board are disposed in a direction perpendicular to the rotation axis, the first inverter device is disposed closer to the motor device than the second inverter device, An electric propulsion unit in which through holes (813d, 821d, 813s, 813c, 821c) in which the second bus bars are arranged are formed in the first wiring board.

2. the first inverter device has a first inverter case (83A) that houses the first wiring board, the second inverter device has a second inverter case (83B) that houses the second wiring board, The electric propulsion unit of claim 1 , wherein the first inverter case and the second inverter case are adjacent to each other.

3. The electric propulsion unit according to claim 1 or 2, wherein the second bus bar is disposed inside the first inverter device closer to the rotation axis than the first bus bar.

4. 4. The electric propulsion unit according to claim 3, wherein the second bus bar includes an adjustment conductor (932B) that is disposed inside the second inverter device and has a portion that extends in a direction perpendicular to the rotation axis.

5. The electric propulsion unit according to claim 1 or 2, wherein the first bus bar and the through hole are arranged to be aligned on a straight line that intersects perpendicularly with the rotation axis.

6. the motor device is a six-phase motor; the first inverter device and the first bus bar supply power to three phases of the six-phase motor; the second inverter device and the second bus bar supply power to three phases of the six-phase motor; The electric propulsion unit according to claim 1 or 2, wherein three of the through holes are formed in the first wiring board at equal intervals around the rotation axis.

7. The motor device includes a stator (62), rotors (64a, 64b), a motor shaft (130), and a motor case (70); the first inverter device has a first inverter case (83A) that houses the first wiring board, A gap (125d) is formed between the motor case and the first inverter case to function as a flow path for cooling air, The electric propulsion unit according to claim 1 or 2, wherein the first bus bar and the second bus bar are arranged to cross the gap.

8. The electric propulsion unit according to claim 7 , wherein a portion of the first bus bar located in the gap and a portion of the second bus bar located in the gap are covered with an electrical insulator (94).

9. The first inverter case has a through-flow passage (83c) formed therethrough along the rotation axis, The outer peripheral surface of the motor case functions as a wall surface of an outer peripheral flow path (125a) through which the fluid flows in the direction of the rotation axis, The electric propulsion unit according to claim 7 , wherein the gap functions as a communication passage that connects the through-flow passage and the outer peripheral passage.

10. a first DC bus bar (91A, 92A) that forms a power supply path from the battery to the first inverter device; a DC second bus bar (91B, 92B) that forms a power supply path from the battery to the second inverter device, The electric propulsion unit according to claim 1 or 2, wherein the second wiring board is formed with a DC through hole (813c, 821c) in which the first DC bus bar is arranged.

11. The electric propulsion unit according to claim 10 , wherein the DC through-hole is formed at a position closer to the rotation axis than the through-hole.

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