Electric driving device

Abstract

To provide an electric driving device which can shorten a wire connected to a rotary electric machine and can increase an electric reliability.SOLUTION: A driving device 16 for propulsion includes: one shaft 38 extending in a predetermined axial direction; a front electric motor 31A and a back electric motor 31B arranged axially with the shaft 38 and connected to the shaft 38; an upper controller 72A electrically connected to the electric motor 31A, the upper controller controlling driving of the electric motor 31A; and a lower controller 72B electrically connected to the electric motor 31B, the lower controller controlling driving of the electric motor 31B. The front and back electric motors 31 are separate from each other in an axial direction of the shaft 38 and the controllers 72 are arranged between the front and back electric motors 31.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to an electric drive device.

Background Art

[0002] In recent years, efforts to achieve a low-carbon or decarbonized society have become active, and research and development on electrification technologies have been carried out in vehicles as well to reduce CO2 emissions and improve energy efficiency. According to research on electrification technologies, electric vehicles are becoming increasingly common, but electric airplanes are not yet common. Airplanes have very high safety standards and need to meet these standards for certification. Thus, high reliability is required for electric drive devices used in electric airplanes and the like.

[0003] For example, Patent Document 1 discloses an electric airplane having a two-motor propulsion system. Electric airplanes include electric vertical takeoff and landing (eVTOL) airplanes. This propulsion system includes a flight component configured to generate thrust, a first electric motor, and a second electric motor, with each of the two electric motors being mechanically connected to the flight component and configured to provide power to the flight component. Specifically, the first electric motor and the second electric motor are coaxially arranged on a single rotor shaft, and the first motor is arranged so as to be stacked on the second motor. In this propulsion system, even when the first electric motor is not operating, the second electric motor can provide power to the flight component.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, in the propulsion system described in Patent Document 1, both the first inverter that generates the power supplied to the first electric motor and the second inverter that generates the power supplied to the second electric motor are disposed below both electric motors. Therefore, the wiring connecting the upper first electric motor and the first inverter needs to be routed avoiding the lower second electric motor. Therefore, not only is a design that takes into account the routing of the wiring necessary, but the wiring becomes long. When the wiring becomes long, the possibility of the wiring being cut increases, leading to a decrease in the electrical reliability of the propulsion system.

[0006] In order to solve the above problems, an object of the present application is to provide an electric drive device that can shorten the wiring connected to the rotating electrical machine and improve the electrical reliability. And, by extension, it is an object to contribute to the reduction of CO2 emissions by the spread of the electric drive device.

Means for Solving the Problems

[0007] In order to solve the above problems, an aspect of the present invention is an electric drive device (16), comprising: a single shaft (38) extending in a predetermined axial direction; a first rotating electrical machine (31A) and a second rotating electrical machine (31B) disposed coaxially with the shaft and connected to the shaft; a first control device (72A) electrically connected to the first rotating electrical machine and controlling the drive of the first rotating electrical machine; and a second control device (72B) electrically connected to the second rotating electrical machine and controlling the drive of the second rotating electrical machine, wherein the first rotating electrical machine and the second rotating electrical machine are disposed apart from each other in the axial direction of the shaft, and the first control device and the second control device are disposed between the first rotating electrical machine and the second rotating electrical machine.

[0008] According to this aspect, in an electric drive device in which two rotating electrical machines coaxially arranged on a shaft and their respective control devices are integrated, by arranging the respective control devices in the space between the rotating electrical machines, each of the control devices in this space can be connected to the corresponding rotating electrical machine with the shortest wiring. Further, there is no need to route these wirings so as to bypass the rotating electrical machines. Therefore, the electrical reliability of the electric drive device can be improved.

[0009] In the above aspect, it is preferable that the electric drive device further includes a casing (71) that defines a control device accommodation space (73) for accommodating the first control device and the second control device between the first rotating electrical machine and the second rotating electrical machine, and two electrical connectors (76) provided on the outer peripheral surface of the casing and connected to the first control device and the second control device.

[0010] According to this aspect, a power line connected to an external power source or battery can be connected to an electrical connector provided on the outer peripheral surface of the casing. Further, since the electrical connector is provided on the outer peripheral surface of the casing, the length of the power line connecting the electrical connector and each control device can be shortened.

[0011] In the above aspect, the first control device is arranged in a first sector-shaped space (119) centered on the shaft in the control device accommodation space, the second control device is arranged in a second sector-shaped space (120) centered on the shaft that does not overlap with the first space in the control device accommodation space, and it is preferable that the first control device and the second control device are arranged so as to overlap each other in the axial direction of the shaft.

[0012] According to this aspect, by arranging the two control devices so as not to overlap in the circumferential direction and to overlap in the axial direction of the shaft in the control device accommodation space between the rotating electrical machines, the dead space can be reduced. Therefore, the axial dimension of the control device accommodation space can be reduced to make the electric drive device compact.

[0013] In the above aspect, it is preferable that the first control device and the second control device are arranged to be rotationally symmetric about the center of the control device accommodation space.

[0014] According to this aspect, an electric drive device can be configured by preparing two combinations of a rotating electrical machine and a control device having the same arrangement and assembling them in a rotationally symmetric arrangement. Therefore, the components of both combinations can be shared, thereby reducing the cost of the electric drive device.

[0015] In the above aspect, it is preferable that the casing includes a cylindrical case body (93), a first wall (94) and a second wall (95) provided on both end faces in the axial direction of the case body, the first wall having a first opening (116) at a position corresponding to the first control device, and the second wall having a second opening (117) at a position corresponding to the second control device.

[0016] According to this configuration, the first control device can be arranged in the first space using the first opening, and the second control device can be arranged in the second space using the second opening. Also, the first control device and the first rotating electrical machine can be electrically connected through the first opening, and the second control device and the second rotating electrical machine can be electrically connected through the second opening.

[0017] In the above aspect, each of the first control device and the second control device includes a power module (77) including a switching element (128) and a smoothing capacitor (79) that smooths the power supplied from a power source (125) to the power module. It is preferable that the power module is attached to the case body and cooling fins (96) are provided on at least the outer surface of the part of the case body corresponding to the power module.

[0018] According to this aspect, since the heat of the power module, which is likely to become high temperature, is released to the outside from the cooling fins through the case body, overheating of the power module is suppressed.

[0019] In the above aspect, it is preferable that the smoothing capacitor is attached to the first wall or the second wall located on the side away from the corresponding first rotating electric machine or the second rotating electric machine.

[0020] According to this aspect, since the smoothing capacitor can be attached to the first wall by accessing the second opening of the second wall, or to the second wall by accessing the first opening of the first wall, the attachment of the smoothing capacitor is easy.

[0021] In the above aspect, it is preferable that the smoothing capacitor is arranged on the side away from the corresponding first rotating electric machine or the second rotating electric machine with respect to the corresponding power module.

[0022] According to this aspect, each rotating electric machine and the corresponding power module are arranged close to each other, and the space between the rotating electric machine on the side different from the corresponding rotating electric machine and the power module can be used as the arrangement space for each smoothing capacitor, so that the space can be effectively utilized.

[0023] In the above aspect, it is preferable that the smoothing capacitor is arranged inside the casing in the radial direction with respect to the corresponding power module.

[0024] According to this aspect, since it is not necessary to extend the control device accommodation space in the axial direction to secure the arrangement space for each smoothing capacitor, by arranging each rotating electric machine and the corresponding power module close to each other, the axial dimension of the casing can be reduced and the electric drive device can be made compact.

Effect of the Invention

[0025] According to the above aspect, it is possible to provide an electric drive device capable of shortening the wiring connected to the rotating electric machine and improving the electrical reliability.

Brief Description of the Drawings

[0026]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Mode for Carrying Out the Invention

[0027] <Aircraft 1> Hereinafter, with reference to the drawings, an aircraft 1 (an example of a moving body) according to an embodiment of the present invention will be described.

[0028] Referring to FIG. 1, the aircraft 1 is an electric vertical take-off and landing aircraft (eVTOL) capable of vertical take-off and landing. The aircraft 1 includes a fuselage 2 extending in the front-rear direction, a front wing 3 extending in the left-right direction and connected to the front part of the fuselage 2, a rear wing 4 extending in the left-right direction and connected to the rear part of the fuselage 2, a left arm 5L extending in the front-rear direction and connecting the left end of the front wing 3 and the left side of the rear wing 4, and a right arm 5R extending in the front-rear direction and connecting the right end of the front wing 3 and the right side of the rear wing 4.

[0029] A cabin (not shown) for passengers to board is provided at the front part of the fuselage 2. At the rear end of the fuselage 2, left and right propulsion units 7 (details will be described later) for generating a forward propulsion force for the aircraft 1 are provided.

[0030] On the left arm 5L and the right arm 5R, a plurality (for example, four) of lifting units 10 for generating lift and downward force on the aircraft 1 are provided at intervals in the front-rear direction. Each lifting unit 10 includes a lifting drive device 12 and a lifting propeller 13 attached to the lifting drive device 12. The lifting drive device 12 has an electric motor (not shown), and is configured to rotate the lifting propeller 13 by the driving force of this electric motor.

[0031] <Propulsion unit 7> Referring to FIG. 2, each propulsion unit 7 includes a support 15, a propulsion drive device 16 (an example of an electric drive device) supported by the support 15, a rotary shaft 17 extending in the front-rear direction and rotatably supported by the propulsion drive device 16, and a propulsion propeller 18 fixed to the rear portion of the rotary shaft 17.

[0032] The support 15 is fixed to the rear end portion of the fuselage 2 (see FIG. 1). The support 15 includes a cylindrical nacelle 20 extending in the front-rear direction and a mount frame 21 fixed to the inner peripheral surface of the nacelle 20. The mount frame 21 includes an annular hub 23 provided concentrically with the nacelle 20 and a plurality of spokes 24 extending radially from the outer peripheral surface of the hub 23 and connected to the inner peripheral surface of the nacelle 20.

[0033] The propulsion drive device 16 is housed in the nacelle 20. The propulsion drive device 16 is fixed to the front surface of the hub 23 of the mount frame 21. Details of the propulsion drive device 16 will be described later.

[0034] The rotary shaft 17 is housed in the nacelle 20. The rotary shaft 17 penetrates the hub 23 of the mount frame 21. A conical front cover 26 that expands in diameter rearward is fixed to the front end portion of the rotary shaft 17. The front cover 26 is disposed in front of the propulsion drive device 16. A conical rear cover 27 that expands in diameter forward is fixed to the rear end portion of the rotary shaft 17. The rear cover 27 is disposed behind the central portion of the propulsion propeller 18.

[0035] The propulsion propeller 18 is housed in the nacelle 20. The propulsion propeller 18 is configured to generate a forward propulsion force for the aircraft 1 by rotating integrally with the rotary shaft 17 as the rotary shaft 17 rotates.

[0036] <Propulsion drive device 16> Referring to FIGS. 2 and 3, each propulsion drive device 16 includes a front electric motor 31A and a rear electric motor 31B (an example of a first rotating electric machine and a second rotating electric machine) arranged to be spaced apart in the front-rear direction, and a control unit  32 arranged between both electric motors 31. Hereinafter, when the front electric motor 31A and the rear electric motor 31B are not distinguished, they are simply referred to as the electric motor 31. Further, when referring to the front electric motor 31A and the rear electric motor 31B, they are referred to as both electric motors 31. Each propulsion drive device 16 further includes a duct cover 34 that covers the outer peripheries of both electric motors 31 and the control unit 32.

[0037] <Electric motor 31> The electric motor 31 is, for example, an inner rotor type three-phase AC motor. Referring to FIGS. 3 and 4, each electric motor 31 has a housing 36, a lid body 37 (37A, 37B), a shaft 38, a rotor 39, and a stator 40. Both electric motors 31 have different configurations in the lid body 37 and generally the same configurations in other respects. Hereinafter, unless otherwise specified, the description of the electric motor 31 applies to both electric motors 31.

[0038] The housing 36 is cylindrical and extends in the front-rear direction on the outer periphery of the shaft 38. The housing 36 is arranged on the outer peripheries of the rotor 39 and the stator 40 and houses the rotor 39 and the stator 40 (an example of a component of the electric motor 31).

[0039] The cover 37A of the front electric motor 31A is attached to the front end of the housing 36 so as to close the front opening of the housing 36. The cover 37B of the rear electric motor 31B is attached to the rear end of the housing 36 so as to close the rear opening of the housing 36. When not distinguishing between the front cover 37A and the rear cover 37B, they are simply referred to as the cover 37.

[0040] On the outer peripheral surface of the housing 36, a plurality of first cooling fins 42 project at intervals in the circumferential direction of the housing 36. The plurality of first cooling fins 42 are integrally formed with the housing 36. Each first cooling fin 42 has a flat plate shape and extends along the front-rear direction. Each first cooling fin 42 continuously extends from the front end portion (one end portion in the front-rear direction) of the housing 36 to the rear end portion (the other end portion in the front-rear direction).

[0041] On the outer peripheral surface of the housing 36, a plurality of fastening protrusions 43 project at intervals in the circumferential direction of the housing 36. The plurality of fastening protrusions 43 are provided between adjacent first cooling fins 42. A cooling air flow path P that is continuous from the front end portion to the rear end portion of the housing 36 is formed between adjacent first cooling fins 42 and between each adjacent first cooling fin 42 and each fastening protrusion 43. The plurality of fastening protrusions 43 are integrally formed with the housing 36.

[0042] Each fastening protrusion 43 has a rod shape with a substantially rectangular cross-section whose tip forms a semi-circle and extends along the front-rear direction. That is, each fastening protrusion 43 extends parallel to each first cooling fin 42. Each fastening protrusion 43 continuously extends from the front end portion (one end portion in the front-rear direction) of the housing 36 to the rear end portion (the other end portion in the front-rear direction). Each fastening protrusion 43 is integrally formed of the same material from the front end portion (one end portion in the front-rear direction) to the rear end portion (the other end portion in the front-rear direction).

[0043] At the front end of each fastening projection 43 of the front electric motor 31A, a first bolt hole 44 for fastening the front cover 37A to the housing 36 is provided. At the rear end of each fastening projection 43, a second bolt hole 45 for fastening the casing 71 of the control unit 32, which will be described later, to the housing 36 is provided. The first bolt hole 44 and the second bolt hole 45 extend along the front-rear direction.

[0044] At the rear end of each fastening projection 43 of the rear electric motor 31B, a first bolt hole 44 for fastening the rear cover 37B to the housing 36 is provided. At the front end of each fastening projection 43, a second bolt hole 45 for fastening the casing 71 of the control unit 32, which will be described later, to the housing 36 is provided. The first bolt hole 44 and the second bolt hole 45 extend along the front-rear direction.

[0045] The front cover 37A is adjacent to the front housing 36 and closes the opening on the front side (opposite to the control unit 32) of the front housing 36. The front cover 37A is disc-shaped and extends along a plane orthogonal to the front-rear direction. The front cover 37A is formed separately from the front housing 36. In other embodiments, the front cover 37A may be formed integrally with the front housing 36.

[0046] The rear cover 37B is adjacent to the rear housing 36 and closes the opening on the rear side (opposite to the control unit 32) of the rear housing 36. The rear cover 37B is conical disc-shaped and extends along a plane orthogonal to the front-rear direction. The rear cover 37B is formed separately from the rear housing 36. In other embodiments, the rear cover 37B may be formed integrally with the rear housing 36.

[0047] On the outer peripheral portion of each lid body 37, a plurality of first fastening pieces 47 project at intervals in the circumferential direction of the lid body 37. A first fastening hole 48 is provided in each first fastening piece 47 in the front-rear direction, and the lid body 37 is fastened to the housing 36 by engaging a first fastening bolt 49 passing through the first fastening hole 48 with a first bolt hole 44 of each fastening projection 43 of the housing 36. A circular first through hole 51 is provided in the central portion of the lid body 37 in the front-rear direction. A first bearing 52 is attached to the first through hole 51.

[0048] Referring to FIG. 2, the shaft 38 extends in the front-rear direction (an example of a predetermined axial direction). The shaft 38 forms a part of the rotating shaft 17 of the propulsion unit 7. Therefore, when the shaft 38 rotates, the entire rotating shaft 17 rotates, and the propulsion propeller 18 rotates integrally with the rotating shaft 17. As a result, a forward propulsion force is generated on the aircraft 1, and the aircraft 1 propels forward. The shaft 38 extends along the propulsion direction of the aircraft 1 (refer to the arrow X in FIG. 2).

[0049] In this embodiment, the shaft 38 is constituted by a single shaft member common to the front and rear electric motors 31. In other embodiments, the front and rear electric motors 31 may each have a shaft member, and the shaft 38 may be constituted by coaxially arranging and connecting those shaft members to each other.

[0050] Referring to FIG. 4, the shaft 38 is hollow. The shaft 38 is provided so as to penetrate the inside of the control unit 32 in the front-rear direction and also penetrate the front and rear housings 36. The shaft 38 penetrates the first through hole 51 of the front lid body 37A and extends forward, and supports the front cover 26 (refer to FIG. 2) at the front end. The shaft 38 is rotatably supported by the front lid body 37A via the first bearing 52. The shaft 38 has a rear end located in the first through hole 51 of the rear lid body 37B, and is connected to the front end of the rotating shaft 17 (FIG. 2) at the rear end. The shaft 38 is rotatably supported by the rear lid body 37B via the first bearing 52.

[0051] The rotor 39 is hollow. The rotor 39 is disposed on the outer periphery of the shaft 38. The rotor 39 has a cylindrical rotor core 61 extending in the front-rear direction, rotor plates 62 extending in the radial direction and connecting the shaft 38 and the rotor core 61, and a plurality of permanent magnets 63 fixed to the outer peripheral surface of the rotor core 61. The rotor core 61 and the rotor plates 62 are integrally formed with the shaft 38. The rotor plates 62 are provided with a plurality of communication holes (not shown) penetrating in the front-rear direction.

[0052] The stator 40 is disposed on the outer periphery of the rotor 39 and is opposed to the rotor 39 with a gap therebetween. The stator 40 has a cylindrical stator core 67 extending in the front-rear direction, a plurality of teeth 68 protruding from the inner peripheral surface of the stator core 67, a plurality of coils 69 wound around the plurality of teeth 68, and three motor-side terminals 70 (see FIG. 5, an example of the terminals on the rotating electrical machine side) connected to the plurality of coils 69. The stator core 67 is fixed to the inner peripheral surface of the housing 36. Among the components of the electric motor 31 and the control unit 32, the plurality of coils 69 generate the largest amount of heat. Therefore, the amount of heat generated by the electric motor 31 is larger than the amount of heat generated by the control unit 32. The three motor-side terminals 70 respectively correspond to the U-phase, V-phase, and W-phase of the three-phase alternating current.

[0053] <Control unit 32> Referring to FIG. 3, the control unit 32 is integrated with the front and rear electric motors 31 and controls the driving of the front and rear electric motors 31. That is, the propulsion drive device 16 of the present embodiment is an electromechanical integrated drive device.

[0054] Referring to FIG. 4, the control unit 32 includes a casing 71 and two control devices 72 (72A, 72B) disposed at the upper and lower portions within the casing 71. The upper control device 72A (an example of the first control device) is for controlling the drive of the front electric motor 31A, and the lower control device 72B (an example of the second control device) is for controlling the drive of the front electric motor 31B. Hereinafter, when not distinguishing between the upper control device 72A and the lower control device 72B, it is simply referred to as the control device 72. Also, when referring to the upper control device 72A and the lower control device 72B, both control devices 72 are referred to.

[0055] The casing 71 of the control unit 32 is disposed between the housings 36 of the front and rear electric motors 31. The casing 71 is formed of metal and defines a control device accommodation space 73 inside for accommodating both control devices 72 between the front and rear electric motors 31.

[0056] Connected to each control device 72 are a communication connector 75 (see FIG. 6) and a DC input connector 76 (see FIGS. 3 and 6, an example of an electrical connector). Each control device 72 includes three power modules 77 fixed by a fixing member (not shown), a smoothing capacitor 79, two DC busbars 82, three AC busbars 84, three current sensors 85, and a substrate 87.

[0057] The casing 71 has a cylindrical peripheral wall portion 93 (an example of a case body) extending in the front-rear direction on the outer periphery of the shaft 38. The peripheral wall portion 93 constitutes the case body of the casing 71 that defines the control device accommodation space 73. The casing 71 also has a front wall portion 94 (an example of the first wall) that closes the front opening facing the front electric motor 31A of the peripheral wall portion 93 and a rear wall portion 95 (an example of the second wall) that closes the rear opening facing the rear electric motor 31B of the peripheral wall portion 93.

[0058] In the following descriptions of the components of the control unit 32, when the "circumferential direction" is mentioned, it refers to the circumferential direction of the peripheral wall portion 93 of the casing 71 (in other words, the circumferential direction centered on the shaft 38). When the "axial direction" is mentioned in the descriptions of the components of the control unit 32, it refers to the axial direction of the peripheral wall portion 93 of the casing 71 (in other words, the axial direction of the shaft 38). When the "radial axial direction" is mentioned in the descriptions of the components of the control unit 32, it refers to the radial direction of the peripheral wall portion 93 of the casing 71 (in other words, the radial direction of the shaft 38).

[0059] Referring to FIGS. 3 and 4, on the outer peripheral surface of the peripheral wall portion 93 of the casing 71, a plurality of second cooling fins 96 project at intervals in the circumferential direction. The plurality of second cooling fins 96 are integrally formed with the peripheral wall portion 93. Each second cooling fin 96 is in a flat plate shape and extends along the front-rear direction. Each second cooling fin 96 continuously extends from the front end portion (one end portion in the front-rear direction) to the rear end portion (the other end portion in the front-rear direction) of the peripheral wall portion 93.

[0060] No second cooling fins 96 are provided on the left side outer peripheral surface portion of the peripheral wall portion 93. Instead, two DC input connectors 76 are provided. One DC input connector 76 is for supplying DC power to the upper control device 72A. The other DC input connector 76 is for supplying DC power to the lower control device 72A.

[0061] On the front end portion and the rear end portion of the outer peripheral surface of the casing 71 respectively, a plurality of second fastening pieces 97 project at intervals in the circumferential direction. Each second fastening piece 97 is provided with a second fastening hole 98 in the front-rear direction. The casing 71 is fastened to the front and rear housings 36 by engaging a second fastening bolt 99 passing through the second fastening hole 98 with the second bolt holes 45 of the respective fastening protrusions 43 of the front and rear housings 36.

[0062] Referring to FIG. 4, on the inner peripheral surface of the peripheral wall portion 93 of the casing 71, a total of six pedestal portions 105, three on the upper side and three on the lower side, protrude at intervals in the circumferential direction. The three power modules 77 of the upper control device 72A are in contact with the inner surfaces of the three pedestal portions 105 arranged at the upper part of the peripheral wall portion 93 of the casing 71. The three power modules 77 of the lower control device 72B are in contact with the inner surfaces of the three pedestal portions 105 arranged at the lower part of the peripheral wall portion 93 of the casing 71.

[0063] The circumferential position of each power module 77 does not overlap with the circumferential position of the plurality of second fastening pieces 97 (i.e., the fastening points between the casing 71 and the housing 36), and overlaps with the circumferential position of the plurality of second cooling fins 96.

[0064] The front wall portion 94 and the rear wall portion 95 of the casing 71 are disc-shaped and extend along a plane orthogonal to the front-rear direction. The front wall portion 94 and the rear wall portion 95 are formed separately from the peripheral wall portion 93 and are fixed to the peripheral wall portion 93 by appropriate means. In other embodiments, the front wall portion 94 may be integrally formed with the peripheral wall portion 93.

[0065] Circular second through holes 113 are provided in the central portions of the front wall portion 94 and the rear wall portion 95 of the casing 71 in the front-rear direction. A third bearing 114 is attached to each second through hole 113. A shaft 38 passes through the second through hole 113. The shaft 38 is rotatably supported by the front wall portion 94 and the rear wall portion 95 of the casing 71 via the third bearing 114.

[0066] A fan-shaped first opening 116 centered on the shaft 38 is formed in the upper part of the front wall portion 94. A fan-shaped second opening 117 centered on the shaft 38 is formed in the lower part of the rear wall portion 95. Three non-illustrated AC lines from the coil 69 of the front electric motor 31A to the three motor-side terminals 70 (FIG. 5) are wired to pass through the first opening 116. Three non-illustrated AC lines from the coil 69 of the rear electric motor 31B to the three motor-side terminals 70 (FIG. 5) are wired to pass through the second opening 117.

[0067] On the front wall portion 94 and the rear wall portion 95 of the casing 71, a resolver (not shown) is provided on the side opposite to the side where the third bearing 114 is provided. The resolver includes a plurality of detection portions provided at intervals in the circumferential direction, and detects the rotation of the shaft 38.

[0068] Referring to FIG. 5, the DC input connector 76 is connected to a DC power supply device 125 provided outside the propulsion drive device 16. For example, the DC power supply device 125 is constituted by a battery or a generator.

[0069] Note that the propulsion drive device 16 includes two control devices 72 and two electric motors 31, but only one control device 72 and one electric motor 31 are shown in FIG. 5.

[0070] Referring to FIG. 3, the DC input connector 76 is fitted into the first fitting hole 118 of the peripheral wall portion 93 of the casing 71 and penetrates the peripheral wall portion 93 of the casing 71. On the inner surface (the surface on the electric motor 31 side) of the DC input connector 76, a pair of DC input terminals to which two DC busbars 82 (FIG. 4) are connected are provided.

[0071] Referring to FIG. 5, the three power modules 77 each include two switching elements 128. That is, the control device 72 includes a total of six switching elements 128. The six switching elements 128 constitute an inverter 130 (an example of a power conversion circuit) that converts DC power (DC current) input from the DC power supply device 125 via a pair of DC lines 129 into AC power (AC current). Each switching element 128 is constituted by a semiconductor element such as an IGBT or a MOSFET. Each switching element 128 is arranged in parallel with a freewheel diode 131.

[0072] The smoothing capacitor 79 is connected in parallel with the inverter 130 to the DC power supply device 125. The smoothing capacitor 79 smooths the DC current input from the DC power supply device 125 to the inverter 130. More specifically, the smoothing capacitor 79 protects the three power modules 77 by smoothing the pulsed current (pulse-shaped current caused by the surge voltage) generated in the DC current input from the DC power supply device 125 to the three power modules 77.

[0073] Referring to FIG. 4, the smoothing capacitor 79 of the upper control device 72A is attached to the rear wall portion 95 of the casing 71. The smoothing capacitor 79 of the lower control device 72B is attached to the front wall portion 94 of the casing 71. Each smoothing capacitor 79 is provided at a distance from the inner peripheral surface of the peripheral wall portion 93 of the casing 71. Each smoothing capacitor 79 is disposed on the upper or lower side of the casing 71 together with the corresponding three power modules 77.

[0074] Specifically, the upper control device 72A is disposed in the upper space 119 (an example of the first space) of the control device accommodation space 73. The lower control device 72B is disposed in the lower space 120 (an example of the second space) of the control device accommodation space 73. Each control device 72 includes electronic components such as three power modules 77, a smoothing capacitor 79, three current sensors 85, a substrate 87, and an AC bus bar 84, and does not include a DC input connector 76. The upper space 119 is a fan-shaped space centered on the shaft 38, and the angle of the fan shape is less than 180°. The lower space 120 is a fan-shaped space centered on the shaft 38 that does not overlap with the upper space 119 in the circumferential direction, and the angle of the fan shape is less than 180°.

[0075] The upper control device 72A is disposed over the entire upper space 119 in the axial direction. The lower control device 72B is disposed over the entire lower space 120 in the axial direction. That is, the upper control device 72A and the lower control device 72B are disposed in the control device accommodation space 73 at positions that do not overlap with each other in the circumferential direction and overlap with each other in the axial direction.

[0076] Referring to FIG. 5, the alternating current output from the inverter 130 (three power modules 77) is output to each coil 69 of the electric motor 31 via each AC output terminal 132 and each motor-side terminal 70.

[0077] Referring to FIGS. 4 and 5, the three current sensors 85 are respectively arranged on three AC busbars 84 (three-phase lines) from the inverter 130 (three power modules 77) to each coil 69 of the electric motor 31. The current sensor 85 detects the value of the current output from the three power modules 77. The three AC busbars 84 are supported by three busbar fastening stays 135 attached to the inner peripheral surface of the peripheral wall portion 93 of the casing 71.

[0078] The substrate 87 is an ECU substrate that controls the drive of the inverter 130 (three power modules 77). The substrate 87 is arranged between the power module 77 and the busbar fastening stay 135, and may be attached to the peripheral wall portion 93 of the casing 71 via a member that presses the power module 77 against the pedestal portion 105, for example.

[0079] <Duct cover 34> Referring to FIGS. 3 and 4, the duct cover 34 has a cylindrical shape extending in the front-rear direction. A cooling air flow path P is formed between the duct cover 34, the housing 36 of the electric motor 31, and the peripheral wall portion 93 of the casing 71 of the control unit 32. That is, the cooling air flow path P is formed on the outer periphery of the housing 36 of the electric motor 31 and the casing 71 of the control unit 32. The cooling air flow path P has a cylindrical shape and extends in the front-rear direction.

[0080] <Cooling of the electric motor 31 and the control unit 32> Referring to FIGS. 2 to 4, when the electric motor 31 is driven and the shaft 38 rotates, the propulsion propeller 18 fixed to the rotary shaft 17 rotates integrally with the shaft 38. As a result, a part of the air flowing rearward in the nacelle 20 by the propulsion propeller 18 flows as cooling air between the outer peripheral surface of the housing 36 and the outer peripheral surface of the peripheral wall portion 93 of the casing 71 and the duct cover 34. That is, the cooling air is introduced into the cooling air flow path P by the propulsion propeller 18.

[0081] The cooling air introduced into the cooling air flow path P flows from the front side to the rear side between the outer periphery of the housing 36 of the front electric motor 31A and a plurality of first cooling fins 42. Thereby, the front electric motor 31A is cooled by the cooling air. Next, the cooling air flows from the front side to the rear side between the outer periphery of the peripheral wall portion 93 of the casing 71 of the control unit 32 and a plurality of second cooling fins 96. Thereby, the housing 36 of the control unit 32 is cooled by the cooling air. Thereafter, the cooling air flows from the front side to the rear side between the outer periphery of the housing 36 of the rear electric motor 31B and a plurality of first cooling fins 42. Thereby, the rear electric motor 31B is cooled by the cooling air. The cooling air that has passed through the outer periphery of the rear electric motor 31B is discharged from the rear end portion of the cooling air flow path P to the rear space.

[0082] FIG. 6 is a (A) front end view and (B) rear end view of the control unit 32. FIG. 6(A) corresponds to a view taken along the arrow VIA in FIG. 4 of the control unit 32, and FIG. 6(B) corresponds to a view taken along the arrow VIB in FIG. 4 of the control unit 32. Referring to FIG. 6, the first opening 116 of the front wall portion 94 is formed in a fan shape at a position corresponding to the upper space 119 of the control device accommodation space 73. The second opening 117 of the rear wall portion 95 is formed in a fan shape at a position corresponding to the lower space 120 of the control device accommodation space 73. The front wall portion 94 and the rear wall portion 95 have a shape that is rotationally symmetric by 180° in their respective front views. The upper control device 72A and the lower control device 72B are also arranged in a rotationally symmetric manner by 180°.

[0083] <Effect> The aircraft 1 and the propulsion drive device 16 according to the embodiment are configured as described above. Hereinafter, the operation and effects of the propulsion drive device 16 having such a configuration will be described.

[0084] Referring to FIG. 2, the propulsion drive device 16 integrally includes a single shaft 38, a front electric motor 31A and a rear electric motor 31B arranged coaxially with the shaft 38, an upper control device 72A, and a lower control device 72B. That is, the propulsion drive device 16 is configured by integrating two electric motors 31 arranged coaxially with the shaft 38 and respective control devices 72. Referring to FIG. 4, both electric motors 31 are arranged apart from each other in the axial direction of the shaft 38, and both control devices 72 are arranged between both electric motors 31. By arranging the respective control devices 72 in the space between both electric motors 31 in this way, each of the control devices 72 in this space can be connected to the corresponding electric motor 31 with the shortest wiring. Also, there is no need to route these wirings so as to bypass the electric motor 31. Therefore, the electrical reliability of the propulsion drive device 16 is improved.

[0085] The propulsion drive device 16 further includes a casing 71 that defines a control device accommodation space 73 for accommodating both control devices 72 between both electric motors 31, and two DC input connectors 76 (FIG. 3) provided on the outer peripheral surface of the casing 71 and connected to both control devices 72. Therefore, a power line connected to an external DC power supply device 125 (FIG. 5) can be connected to the DC input connector 76 provided on the outer peripheral surface of the casing 71. Also, since the DC input connector 76 is provided on the outer peripheral surface of the casing 71, the length of the power line connecting the DC input connector 76 and each control device 72 can be shortened.

[0086] The upper control device 72A is arranged in the upper space 119 of the control device accommodation space 73, and the lower control device 72B is arranged in the lower space 120 of the control device accommodation space 73. Both control devices 72 are arranged so as to overlap each other in the axial direction of the shaft 38. By arranging the two control devices 72 in this way so that they do not overlap in the circumferential direction in the control device accommodation space 73 between the electric motors 31 and overlap in the axial direction of the shaft 38, the dead space is reduced. Therefore, the axial dimension of the control device accommodation space 73 can be made smaller, and the propulsion drive device 16 can be made compact.

[0087] Referring to FIGS. 4 and 6, both control devices 72 are arranged to be rotationally symmetric about the center of the control device accommodation space 73. Therefore, two combinations of the electric motor 31 and the control device 72 with the same arrangement can be prepared, and the propulsion drive device 16 can be configured by assembling them in a rotationally symmetric arrangement. Thus, the parts of both combinations can be made common, and thereby the cost of the propulsion drive device 16 can be reduced.

[0088] The casing 71 includes a front wall portion 94 and a rear wall portion 95 provided on both axial end faces of the cylindrical peripheral wall portion 93. The front wall portion 94 has a first opening 116 at a position corresponding to the upper control device 72A, and the rear wall portion 95 has a second opening 117 at a position corresponding to the lower control device 72B. Therefore, the upper control device 72A can be arranged in the upper space 119 using the first opening 116, and the lower control device 72B can be arranged in the lower space 120 using the second opening 117. Also, the upper control device 72A and the front electric motor 31A can be electrically connected by passing the motor-side AC line through the first opening 116, and the lower control device 72B and the rear electric motor 31B can be electrically connected by passing the motor-side AC line through the second opening 117.

[0089] Each control device 72B includes a power module 77 and a smoothing capacitor 79 that smooths the power supplied from the DC power supply device 125 to the power module 77. The power module 77 is attached to the peripheral wall portion 93, and the second cooling fins 96 are provided on the outer surface of at least the portion of the peripheral wall portion 93 corresponding to the power module 77. Therefore, since the heat of the power module 77 that easily becomes high temperature is released to the outside from the second cooling fins 96 through the peripheral wall portion 93, overheating of the power module 77 is suppressed.

[0090] The smoothing capacitor 79 is attached to the front wall portion 94 or the rear wall portion 95 located on the side away from the corresponding electric motor 31. Therefore, the smoothing capacitor 79 can be attached to the front wall portion 94 by accessing the second opening 117 of the rear wall portion 95, or to the rear wall portion 95 by accessing the first opening 116 of the front wall portion 94. Therefore, it is easy to attach the smoothing capacitor 79.

[0091] Referring to FIGS. 4 and 7, the smoothing capacitor 79 is disposed on the side away from the corresponding electric motor 31 with respect to the corresponding power module 77. Therefore, each electric motor 31 and the corresponding power module 77 are arranged close to each other, and the space between the electric motor 31 on the side different from the corresponding electric motor 31 and the power module 77 can be effectively used as an arrangement space for each smoothing capacitor 79.

[0092] <Modification Example> Next, the propulsion drive device 16 according to the modification example will be described. FIG. 8 is a cross-sectional view corresponding to FIG. 7 schematically showing the upper half of the propulsion drive device 16 according to the modification example. As shown in FIG. 8, in this modification example, the arrangement of the power module 77 and the smoothing capacitor 79 is different from that in the above-described embodiment (FIG. 7). In the above-described embodiment shown in FIGS. 4 and 7, the smoothing capacitor 79 is disposed on the rear side away from the corresponding front-side electric motor 31A with respect to the power module 77.

[0093] In contrast, in this modified example, the smoothing capacitor 79 is arranged inside the casing 71 in the radial direction with respect to the corresponding power module 77. Therefore, it is not necessary to extend the control device accommodation space 73 in the axial direction to secure the arrangement space for each smoothing capacitor 79. Thus, by arranging each electric motor 31 and the corresponding power module 77 in proximity, the axial dimension of the casing 71 can be reduced, and the propulsion drive device 16 can be made compact.

[0094] In the above embodiment, the inner rotor type electric motor 31 is an example of a rotating electrical machine. In other embodiments, an outer rotor type electric motor may be an example of a rotating electrical machine, or a generator may be an example of a rotating electrical machine.

[0095] In the above embodiment, the configuration of the present invention is applied to the propulsion drive device 16. In other embodiments, the configuration of the present invention may be applied to the lifting drive device 12.

[0096] In the above embodiment, the configuration of the present invention is applied to an electric vertical takeoff and landing aircraft. In other embodiments, the configuration of the present invention may be applied to an aircraft other than an electric vertical takeoff and landing aircraft (i.e., a general aircraft that cannot take off and land vertically), or to a moving body other than an aircraft (e.g., vehicles such as automobiles and motorcycles). Further, in other embodiments, the configuration of the present invention may be applied to a fixedly provided device.

[0097] With the above, the description of the specific embodiments is completed. However, the present invention is not limited to the above embodiments and modified examples, and can be widely modified and implemented.

Description of Reference Numerals

[0098] 16: Propulsion drive device (an example of an electric drive device) 31: Electric motor (an example of a rotating electrical machine) 31A: Front electric motor (first rotating electrical machine) 31B: Rear electric motor (second rotating electrical machine) 32: Control unit 38: Shaft 71: Casing 72: Control device 72A: Upper control device (first control device) 72B: Lower control device (second control device) 73: Control device accommodation space 76: DC input connector (an example of an electrical connector) 77: Power module 79: Smoothing capacitor 93: Peripheral wall portion (an example of a case body) 94: Front wall portion (an example of a first wall) 95: Rear wall portion (an example of a second wall) 96: Second cooling fin 119: Upper space (an example of a first space) 120: Lower space (an example of a second space) 125: DC power supply device (an example of a power supply) 128: Switching element

Claims

1. One shaft extending in a predetermined axial direction, A first rotating electric machine and a second rotating electric machine that are coaxially arranged with the shaft and connected to the shaft, A first control device that is electrically connected to the first rotating electric machine and controls the drive of the first rotating electric machine, A second control device that is electrically connected to the second rotating electric machine and controls the drive of the second rotating electric machine, and includes, The first rotating electric machine and the second rotating electric machine are arranged at intervals from each other in the axial direction of the shaft, and the first control device and the second control device are arranged between the first rotating electric machine and the second rotating electric machine. Electric drive device.

2. A casing that defines a control device accommodation space for accommodating the first control device and the second control device between the first rotating electric machine and the second rotating electric machine, The electric drive device according to claim 1, further comprising two electrical connectors provided on an outer peripheral surface of the casing and connected to the first control device and the second control device.

3. The first control device is arranged in a first sector-shaped space centered on the shaft in the control device accommodation space, The second control device is arranged in a second sector-shaped space centered on the shaft that does not overlap with the first space in the control device accommodation space, The electric drive device according to claim 2, wherein the first control device and the second control device are arranged so as to overlap each other in the axial direction of the shaft.

4. The electric drive device according to claim 2 or 3, wherein the first control device and the second control device are arranged to be rotationally symmetric about the center of the control device accommodation space.

5. The casing includes a cylindrical case body, and a first wall and a second wall provided on both end faces in the axial direction of the case body. The first wall has a first opening at a position corresponding to the first control device. The electric drive device according to claim 2 or 3, wherein the second wall has a second opening at a position corresponding to the second control device.

6. Each of the first control device and the second control device includes a power module including a switching element and a smoothing capacitor that smooths the power supplied from a power source to the power module, The electric drive device according to claim 5, wherein the power module is attached to the case body, and cooling fins are provided on at least an outer surface of a portion of the case body corresponding to the power module.

7. The electric drive device according to claim 6, wherein the smoothing capacitor is attached to the first wall or the second wall located on the side away from the corresponding first rotating electric machine or the second rotating electric machine.

8. The electric drive device according to claim 7, wherein the smoothing capacitor is arranged on the side away from the corresponding first rotating electric machine or the second rotating electric machine with respect to the corresponding power module.

9. The electric drive device according to claim 7, wherein the smoothing capacitor is arranged inside the case body in the radial direction with respect to the corresponding power module.

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