Aircraft

Abstract

To provide a cooling system which is simple and light-weight.SOLUTION: A cooling system 60 includes: rotors (VTOL rotors 20 and cruise rotors 22) which generate at least one of a lift force and a thrust force of an air craft 10; component groups 24 each comprising a plurality of electric components which rotate the rotor; and a cooling circuit 62 which cools the component groups 24. The cooling system 60 includes the plurality of component groups 24 corresponding to the multiple rotors. The plurality of component groups 24 are cooled by the same cooling circuit 62.SELECTED DRAWING: Figure 9

Description

Technical Field

[0001] The present invention , Ro relates to a cooling system for cooling an electrical component for rotating a rotor. An aircraft equipped with

Background Art

[0002] Patent Document 1 discloses an aircraft called an electric vertical takeoff and landing aircraft (eVTOL aircraft). This aircraft includes a plurality of takeoff and landing rotors (referred to as VTOL rotors) and a plurality of cruise rotors (referred to as cruise rotors). Each rotor is connected to an electric motor. The electric motor is connected to a power source via a drive circuit (such as an inverter). The electric motor and the drive circuit generate heat as power is supplied. Patent Document 1 discloses cooling the electric motor by air cooling. Further, Patent Document 1 discloses that air cooling is superior to liquid cooling in terms of simplifying and reducing the weight of the system.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Patent Document 1 does not disclose a configuration for cooling the drive circuit of an electric motor. Also, a liquid-cooled electric motor has a higher output density than an air-cooled electric motor. Therefore, when high output is required, a liquid-cooled electric motor is desirable. Further, since air cooling has inferior cooling capacity compared to liquid cooling, there is a possibility that electrical components such as an electric motor and a drive circuit cannot be sufficiently cooled. Therefore, liquid cooling is desirable for sufficiently cooling electrical components.

[0005] ​However, as disclosed in Patent Document 1, liquid cooling has problems such as being complex and heavy. For example, if one cooling circuit is provided for an electric motor and a drive circuit provided corresponding to one rotor, piping and components (radiator, pump, etc.) corresponding to the number of rotors are required, and the entire cooling system becomes complex and heavy.

[0006] The present invention has been made in consideration of such problems, and an object thereof is to provide a simple and lightweight cooling system.

Means for Solving the Problems

[0007] An aspect of the present invention is a rotor that generates at least one of lift and thrust of an aircraft, a component group including a plurality of electrical components that rotate the rotor, a cooling circuit that cools the plurality of electrical components, and a cooling system including a plurality of the component groups corresponding to the plurality of rotors, wherein the plurality of component groups are cooled by the same cooling circuit.

Effects of the Invention

[0008] According to the present invention, the cooling system provided in the aircraft is simplified and lightened.

Brief Description of the Drawings

[0009] [Figure 1] FIG. 1 is a schematic view of an aircraft seen from above. [Figure 2] FIG. 2 is a diagram showing the arrangement of each rotor and each component group in the power supply system. [Figure 3] FIG. 3 is a diagram showing the circuit of the power supply system. [Figure 4] FIG. 4 is a diagram showing the control block of the power supply system. [Figure 5]FIG. 5 is a diagram showing the flight time after takeoff, the input power of the inverter, and the heat dissipation amount per gas-liquid temperature difference. [Figure 6] FIG. 6 is a diagram showing the change of the main body that generates lift force with the change of the flight state. [Figure 7] FIG. 7 is a diagram showing the arrangement of each rotor and each component group in the power supply system. [Figure 8] FIG. 8 is a diagram showing the circuit of the power supply system. [Figure 9] FIG. 9 is a diagram showing the circuit of the cooling system.

DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, a preferred embodiment of the An aircraft and the cooling system according to the present invention will be given and described in detail with reference to the accompanying drawings.

[0011] [1 Configuration of Aircraft 10] The configuration of the aircraft 10 will be described with reference to FIG. 1. In the present embodiment, as the aircraft 10, an electric vertical takeoff and landing aircraft (eVTOL aircraft) that generates lift and thrust with a rotor having an electric motor 26 (FIG. 2) as a drive source is assumed. Further, in the present embodiment, as the aircraft 10, a hybrid aircraft is assumed. The hybrid aircraft can operate the electric motor 26 with the power supplied from the battery 32 (FIG. 2), and can operate the electric motor 26 with the power supplied from the motor generator 42 (FIG. 3). In addition, the hybrid aircraft can charge the battery 32.

[0012] The aircraft 10 includes a fuselage 12, a front wing 14, a rear wing 16, two booms 18, eight VTOL rotors 20, and two cruise rotors 22.

[0013] The front wing 14 is connected to the front part of the fuselage 12 and is configured to generate lift when the aircraft 10 moves forward. The rear wing 16 is connected to the rear part of the fuselage 12 and is configured to generate lift when the aircraft 10 moves forward.

[0014] The two booms 18 consist of a right boom 18R disposed on the right side of the fuselage 12 and a left boom 18L disposed on the left side of the fuselage 12. The two booms 18 are connected to the front wing 14 and the rear wing 16, and are connected to the fuselage 12 via the front wing 14 and the rear wing 16. Both the boom 18R and the boom 18L support four VTOL rotors 20.

[0015] The VTOL rotors 20 are used during vertical takeoff of the aircraft 10, during the transition from vertical takeoff to cruising, during the transition from cruising to vertical landing, during vertical landing, and during stationary flight. The rotation axis of the VTOL rotors 20 is arranged to be parallel to the vertical direction. The VTOL rotors 20 rotate about the rotation axis to generate lift.

[0016] The eight VTOL rotors 20 consist of four VTOL rotors 20Ra to 20Rd disposed on the right side of the fuselage 12 and four VTOL rotors 20La to 20Ld disposed on the left side of the fuselage 12. The right-side VTOL rotors 20Ra to 20Rd are supported by the boom 18R. The right-side VTOL rotors 20Ra to 20Rd are arranged in the order of VTOL rotor 20Ra, VTOL rotor 20Rb, VTOL rotor 20Rc, and VTOL rotor 20Rd from front to rear. The left-side VTOL rotors 20La to 20Ld are supported by the boom 18L. The left-side VTOL rotors 20La to 20Ld are arranged in the order of VTOL rotor 20La, VTOL rotor 20Lb, VTOL rotor 20Lc, and VTOL rotor 20Ld from front to rear. The right-side VTOL rotors 20Ra to 20Rd and the left-side VTOL rotors 20La to 20Ld are arranged symmetrically about a vertical plane including the central axis A of the fuselage 12. Note that the right-side VTOL rotors 20Ra to 20Rd and the left-side VTOL rotors 20La to 20Ld may be arranged to be point-symmetrical with respect to the center of gravity G of the aircraft body.

[0017] The cruise rotor 22 is used during the cruise of the aircraft 10, during the transition from vertical takeoff to cruise, and during the transition from cruise to vertical landing. The axis of rotation of the cruise rotor 22 is arranged to be parallel to the longitudinal direction. The cruise rotor 22 rotates about the axis of rotation to generate thrust.

[0018] The two cruise rotors 22 consist of a cruise rotor 22R arranged on the right side of the fuselage 12 and a cruise rotor 22L arranged on the left side of the fuselage 12. The two cruise rotors 22 are supported by the fuselage 12. The two cruise rotors 22 are arranged symmetrically about a vertical plane including the central axis A of the fuselage 12.

[0019] The aircraft 10 has a drive mechanism (not shown) for rotating the VTOL rotors 20 and the cruise rotors 22 and a power supply system 23 (Figs. 2 and 3). Further, the aircraft 10 has a cooling system 60 (Fig. 9) for cooling each electrical component constituting the power supply system 23.

[0020] [Configuration of Power Supply System 23] The configuration of the power supply system 23 will be described with reference to Figs. 2 and 3. As shown in Fig. 2, a set of component groups 24 is provided for each VTOL rotor 20. Two sets of component groups 24 are provided for each cruise rotor 22. The power supply system 23 shown in Figs. 2 and 3 has 12 sets of component groups 24. Further, this power supply system 23 has four groups (first group G1 to fourth group G4) each consisting of three sets of component groups 24 and one battery 32. Each component group 24 includes a plurality of electrical components, here an electric motor 26, an inverter 28 (INV), and a first smoothing capacitor 30. The electric motor 26 is connected to the battery 32 via the inverter 28 and the first smoothing capacitor 30.

[0021] The electric motor 26 is a three-phase motor. The output shaft of the electric motor 26 is connected to the rotation shaft of the corresponding rotor (VTOL rotor 20 or cruise rotor 22). The inverter 28 has a plurality of switching elements such as IGBTs. The primary side terminals of the inverter 28 are connected to the first smoothing capacitor 30 and the battery 32. The secondary side terminals of the inverter 28 are connected to the electric motor 26. The inverter 28 converts the DC power input to the primary side terminals into three-phase AC power and outputs it from the secondary side terminals. With the above configuration, each electric motor 26 operates with the power supplied from the battery 32.

[0022] As shown in FIG. 3, the primary side terminals of the inverter 28, the first smoothing capacitor 30, and each battery 32 (32a to 32d) are connected to the motor generator 42 via the switch 36, the second smoothing capacitor 38, and the power control unit 40 (PCU 40).

[0023] The motor generator 42 functions as a three-phase motor and also as a three-phase generator. The rotating shaft of the motor generator 42 is connected to the output shaft of the engine 44 (ENG). The PCU 40 has an inverter circuit. The primary side terminals of the PCU 40 are connected to the motor generator 42. The secondary side terminals of the PCU 40 are connected to the second smoothing capacitor 38. Further, the secondary side terminals of the PCU 40 are connected to the battery 32 and the primary side terminals of the inverter 28 via the switch 36. The PCU 40 converts the three-phase AC power input to the primary side terminals into DC power by the inverter circuit and outputs it from the secondary side terminals. Also, the PCU 40 converts the DC power input to the secondary side terminals into three-phase AC power by the inverter circuit and outputs it from the primary side terminals. The switch 36 is composed of a switching element such as an IGBT and a diode. The switch 36 is arranged to always allow the supply of power from the PCU 40 side to the battery 32 side and to allow the supply of power from the battery 32 side to the PCU 40 side during the on-operation. With the above configuration, the motor generator 42 can output the generated power to the battery 32 and the inverter 28. Also, when the switch 36 is on, the motor generator 42 can operate by the power supplied from the battery 32 and start the engine 44. As the engine 44, a well-known internal combustion engine such as a reciprocating engine and a gas turbine engine can be used. Note that the PCU 40 may have a DC / DC converter circuit.

[0024] Note that FIGS. 2 and 3 show the power supply system 23 in a simplified manner. The power supply system 23 includes other electrical components. Examples of the electrical components not shown include electrical loads other than the electric motor 26, resistors, coils, capacitors, various sensors, fuses, relays, breakers, etc.

[0025] As shown in FIG. 4, the aircraft 10 is provided with a controller 48. The controller 48 is constituted by, for example, a processor such as a CPU, or an integrated circuit such as an ASIC or an FPGA. For example, the processor realizes various functions by executing a program stored in a memory. The controller 48 outputs control signals to the switching elements of the respective inverters 28, the switching elements of the respective switches 36, and the switching elements of the power control unit 40, and controls the operations of the respective switching elements.

[0026] [Operation of Power Supply System 23] The operation of the power supply system 23 will be described with reference to FIGS. 2 and 3. When the aircraft 10 starts, the controller 48 turns on at least one switch 36 in response to the operation of the crew member, and controls the operation of each switching element of the PCU 40. Then, power is supplied from at least one battery 32 (32a to 32d) to the motor generator 42 via the PCU 40. At this time, the PCU 40 converts the DC power supplied from the battery 32 into AC power and outputs it to the motor generator 42. When power is supplied, the motor generator 42 operates to start the engine 44.

[0027] After the engine 44 starts, the motor generator 42 generates power by the operation of the engine 44. In this state, power can be supplied from the motor generator 42 to each group of batteries 32 and the component group 24 via the PCU 40. At this time, the PCU 40 converts the AC power generated by the motor generator 42 into DC power and outputs it to each battery 32 and the component group 24. The inverter 28 converts the DC power output from the PCU 40 or the DC power supplied from the battery 32 into AC power and outputs it to the electric motor 26. When power is supplied, the electric motor 26 operates, and the rotor (VTOL rotor 20 or cruise rotor 22) rotates.

[0028] When rotating the electric motor 26 with the power of the battery 32, basically the switching elements of each switch 36 are turned off. Therefore, power is not supplied from one group of batteries 32 to the component group 24 of another group. However, it is also possible to turn on the switching element of the switch 36 to supply power from one group of batteries 32 to the component group 24 of another group.

[0029] [Example of grouping of component group 24 and battery 32] As shown in FIGS. 2 and 3, in the power supply system 23, a plurality of component groups 24 and a plurality of batteries 32 are grouped into four groups (first group G1 to fourth group G4) including three component groups 24 and one battery 32. A plurality of component groups 24 within the same group are supplied with power from one battery 32 within the same group. Here, one battery 32 means one battery module or a plurality of battery modules. The batteries 32 of each group are independent of the batteries 32 of other groups.

[0030] The first group G1 includes a component group 24Ra corresponding to the VTOL rotor 20Ra, a component group 24Ld corresponding to the VTOL rotor 20Ld, a component group 24R1 corresponding to the cruise rotor 22R, and a battery 32a. Each electrical component of the first group G1 is connected by a wiring 34a.

[0031] The second group G2 includes a component group 24La corresponding to the VTOL rotor 20La, a component group 24Rd corresponding to the VTOL rotor 20Rd, a component group 24L1 corresponding to the cruise rotor 22L, and a battery 32b. Each electrical component of the second group G2 is connected by a wiring 34b.

[0032] The third group G3 includes a component group 24Rb corresponding to the VTOL rotor 20Rb, a component group 24Lc corresponding to the VTOL rotor 20Lc, a component group 24R2 corresponding to the cruise rotor 22R, and a battery 32c. Each electrical component of the third group G3 is connected by wiring 34c.

[0033] The fourth group G4 includes a component group 24Lb corresponding to the VTOL rotor 20Lb, a component group 24Rc corresponding to the VTOL rotor 20Rc, a component group 24L2 corresponding to the cruise rotor 22L, and a battery 32d. Each electrical component of the fourth group G4 is connected by wiring 34d.

[0034] For redundancy, the electric motor 26 of the component group 24R1 and the electric motor 26 of the component group 24R2 are connected to the same cruise rotor 22R. Normally, the component groups 24R1 and 24R2 are both used to rotate the cruise rotor 22R. And when one of the component groups 24 fails, the other component group 24 is used to rotate the cruise rotor 22R. Similarly, the electric motor 26 of the component group 24L1 and the electric motor 26 of the component group 24L2 are connected to the same cruise rotor 22L.

[0035] [4.1 Reasons for grouping (1)] From the perspective of reducing the battery 32, it is conceivable to share one battery 32 among all the component groups 24. However, in this case, other problems will occur, such as the need for a large-capacity battery 32. Therefore, it is preferable to divide the battery 32 to some extent. Furthermore, it is preferable to efficiently combine the component group 24 and the battery 32. In this embodiment, the plurality of component groups 24 and the plurality of batteries 32 are divided into four groups (the first group G1 to the fourth group G4) for the following reasons.

[0036] As shown in FIG. 1, in the present embodiment, the two VTOL rotors 20 arranged at positions symmetric to each other about the center of gravity G rotate in opposite directions. For example, the rotation direction of the right VTOL rotor 20Ra is R1. This rotation direction is opposite to the rotation direction (R2) of the left VTOL rotor 20Ld paired with the VTOL rotor 20Ra. Also, the rotation direction of the left VTOL rotor 20La is R2. This rotation direction is opposite to the rotation direction (R1) of the right VTOL rotor 20Rd paired with the VTOL rotor 20La. Also, the rotation direction of the right VTOL rotor 20Rb is R2. This rotation direction is opposite to the rotation direction (R1) of the left VTOL rotor 20Lc paired with the VTOL rotor 20Rb. Also, the rotation direction of the left VTOL rotor 20Lb is R1. This rotation direction is opposite to the rotation direction (R2) of the right VTOL rotor 20Rc paired with the VTOL rotor 20Lb.

[0037] When the VTOL rotor 20 rotates, thrust and reaction force (torque reaction force) are generated by the rotor blade. As described above, by rotating the two paired VTOL rotors 20 in opposite directions, the reaction force generated on the aircraft can be canceled out.

[0038] For example, when an electrical system or a mechanical system associated with one VTOL rotor 20 fails, the VTOL rotor 20 stops. In this case, if the other VTOL rotor 20 paired with the stopped VTOL rotor 20 is kept rotating, the reaction force generated by the other VTOL rotor 20 acts on the airframe without being canceled out. Then, a yaw moment is generated on the airframe. Also, if the other VTOL rotor 20 paired with the stopped VTOL rotor 20 is kept rotating, the balance of the thrusts of the left and right VTOL rotors 20 is disrupted. Then, a roll moment and a pitching moment are generated on the airframe. To avoid such a situation, when one of the paired VTOL rotors 20 stops due to a failure or the like, it is necessary to stop the other VTOL rotor 20. By doing so, it is possible to suppress the yaw moment caused by the imbalance of the reaction forces (torque reaction forces) and the roll moment and pitching moment caused by the imbalance of the thrusts.

[0039] From this, when sharing the battery 32 among a plurality of component groups 24, it is efficient to share the battery 32 among the two component groups 24 corresponding to the two paired VTOL rotors 20. Therefore, in the present embodiment, the two component groups 24 corresponding to the two paired VTOL rotors 20 and one battery 32 are grouped together into the same group.

[0040] Note that the two VTOL rotors 20 that cancel out the reaction forces with each other may be in a combination different from the above example. For example, two laterally adjacent VTOL rotors 20 such as the VTOL rotor 20Ra and the VTOL rotor 20La may form a pair. Also, two VTOL rotors 20 arranged front and back with one VTOL rotor 20 in between, such as the VTOL rotor 20Ra and the VTOL rotor 20Rc, may form a pair. Additionally, two VTOL rotors 20 with opposite rotation directions may form a pair. Based on the above idea, for rotors other than the VTOL rotor 20 shown in FIG. 1, it is possible to set the combination of the paired rotors by setting the rotation direction of each rotor.

[0041] [Reasons for Grouping (2) in 4.2] The horizontal axis shown in FIG. 5 is the flight time [s] of the aircraft 10. The vertical axis shown in FIG. 5 is the power [W] input from the battery 32 or the motor generator 42 to the inverter 28 and the heat dissipation per unit temperature Difference quantity [W / K]. The heat dissipation per unit temperature Difference The heat dissipation per unit temperature is defined as the heat dissipation amount / (refrigerant temperature - outside air temperature). Also, the heat dissipation per unit temperature Difference The heat dissipation per unit temperature is correlated with the heat generation amount [W] of the inverter 28 (and the electric motor 26). The heat dissipation per unit temperature Difference The transitions of the heat dissipation per unit temperature and the heat generation amount [W] of the inverter 28 (and the electric motor 26) may have the same characteristics as the fourth transition 56 described later.

[0042] In FIG. 5, the changes over time of three powers and one thermal resistance are shown as the first transition 50 to the fourth transition 56. The first transition 50 shows the transition of the input power of the two inverters 28 corresponding to the two VTOL rotors 20. The two VTOL rotors 20 are a pair of two VTOL rotors 20 (see the above [4.1]). The second transition 52 shows the transition of the input power of the one inverter 28 corresponding to the one cruise rotor 22. The third transition 54 shows the transition of the total value of the input power of the first transition 50 and the input power of the second transition 52. The fourth transition 56 shows the transition of the value obtained by converting the power of the third transition 54 into the heat dissipation per unit temperature Difference (heat generation amount).

[0043] The flight state from time point t1 to time point t2 is vertical takeoff. In this time period, basically, the VTOL rotors 20 are used and the cruise rotors 22 are not used. For this reason, as shown in the first transition 50, the input power of the inverter 28 corresponding to the VTOL rotors 20 is large. On the other hand, as shown in the second transition 52, the input power of the inverter 28 corresponding to the cruise rotors 22 is small.

[0044] The flight state from time point t2 to time point t3 is the transition from vertical takeoff to cruising. In this time period, basically, the usage rate of the VTOL rotor 20 is gradually decreased, and the usage rate of the cruise rotor 22 is gradually increased. Therefore, as shown by the first transition 50, the input power of the inverter 28 corresponding to the VTOL rotor 20 gradually becomes smaller. On the other hand, as shown by the second transition 52, the input power of the inverter 28 corresponding to the cruise rotor 22 gradually becomes larger.

[0045] The flight state after time point t3 is cruising. In this time period, basically, the cruise rotor 22 is used, and the VTOL rotor 20 is not used or used to a certain extent. Therefore, as shown by the second transition 52, the input power of the inverter 28 corresponding to the cruise rotor 22 is large. On the other hand, as shown by the first transition 50, the input power of the inverter 28 corresponding to the VTOL rotor 20 is small.

[0046] Note that the performance of the cooling system 60 is proportional to the difference between the liquid temperature of the refrigerant and the outside air temperature. Since the outside air temperature decreases as the altitude of the aircraft 10 increases, the cooling capacity of the cooling system 60 increases. That is, the cooling capacity of the cooling system 60 can be higher at time point t2 and later than at time point t1.

[0047] As shown in FIG. 6, the lift force required at the time of vertical takeoff is obtained by the rotation of the VTOL rotor 20 (rotary lift). On the other hand, the lift force required at the transition from vertical takeoff to cruising is obtained by the rotation of the VTOL rotor 20 and also by the wings (the front wing 14 and the rear wing 16). The lift force obtained by the wings (wing lift) increases as the moving speed increases. The lift force required during cruising is obtained by the wings. At the time of vertical takeoff (and vertical landing) when the lift force is generated by the rotation of the VTOL rotor 20, the input power of the inverter 28 corresponding to the VTOL rotor 20 is large. On the other hand, during cruising when the lift force is generated by the wings, the input power of the inverter 28 corresponding to the VTOL rotor 20 is relatively small.

[0048] From the takeoff to the cruise of the aircraft 10 (from time point t1 to time point t3) and during the cruise (after time point t3), the maximum value of the third transition 54 has no significant difference from the maximum values of the first transition 50 and the second transition 52. That is, one battery 32 can be shared by two component groups 24 corresponding to two VTOL rotors 20 and one component group 24 corresponding to one cruise rotor 22. For these reasons, in the present embodiment, two component groups 24 corresponding to two paired VTOL rotors 20, one component group 24 corresponding to one cruise rotor 22, and one battery 32 are grouped together into the same group.

[0049] [4.3 Combination method of the component group 24 of the cruise rotor 22] Each group is composed of a combination of two component groups 24 corresponding to two paired VTOL rotors 20 and a component group 24 corresponding to one cruise rotor 22. The cruise rotors 22 are provided one on each side, left and right. In each group, which combination of the component groups 24R1, 24R2 corresponding to the cruise rotor 22R and the component groups 24L1, 24L2 corresponding to the cruise rotor 22L is adopted is determined by the following idea.

[0050] Of the two paired VTOL rotors 20, let the difference between the length from one VTOL rotor 20 to the right cruise rotor 22R and the length from the other VTOL rotor 20 to the right cruise rotor 22R be D1. Also, let the difference between the length from one VTOL rotor 20 to the left cruise rotor 22L and the length from the other VTOL rotor 20 to the left cruise rotor 22L be D2. In each group, the combination with the smaller difference is adopted.

[0051] For example, it will be described with reference to the first group G1. Let D1 be the difference between the length from the VTOL rotor 20Ra to the right cruise rotor 22R and the length from the VTOL rotor 20Ld to the right cruise rotor 22R. On the other hand, let D2 be the difference between the length from the VTOL rotor 20Ra to the left cruise rotor 22L and the length from the VTOL rotor 20Ld to the left cruise rotor 22L. D1 is smaller than D2. Therefore, the first group G1 is composed of the combination of the component group 24Ra, the component group 24Ld, and the component group 24R1. The same applies to other groups. By doing so, the deviation in the distance between the two component groups 24 within the same group is reduced.

[0052] [Position of the 4.4 battery 32] The battery 32 is arranged such that the length of the wiring 34 is minimized. For example, it will be described with reference to the first group G1. Let L1 be the length of the wiring 34a from the battery 32a to the electric motor 26 that rotates one VTOL rotor 20Ra. Let L2 be the length of the wiring 34a from the battery 32a to the electric motor 26 that rotates the other VTOL rotor 20Ld. Let L3 be the length of the wiring 34a from the battery 32a to the electric motor 26 that rotates the cruise rotor 22R. In this case, the battery 32a is arranged such that the total length value L1 + L2 + L3 is minimized.

[0053] [Another example of grouping the component group 24 and the battery 32] Grouping different from the examples shown in FIGS. 2 and 3 is also possible. For example, grouping as shown in FIGS. 7 and 8 may be used. In this example, a plurality of component groups 24 and a plurality of batteries 32 are grouped into the first group G1 to the fourth group G4. The first group G1 and the second group G2 include four component groups 24 and one battery 32. The third group G3 and the fourth group G4 include two component groups 24 and one battery 32.

[0054] Grouping different from the examples shown in FIGS. 7 and 8 is also possible. For example, one component group 24 corresponding to the VTOL rotor 20, one component group 24 corresponding to one cruise rotor 22, and one battery 32 may be grouped together.

[0055] [Configuration of Cooling System 60] The configuration of the cooling system 60 will be described with reference to FIG. 9. In this embodiment, one independent cooling system 60 is provided for one group of the power supply system 23. Four independent cooling systems 60 are provided in the power supply system 23 shown in FIGS. 2 and 3. FIG. 9 shows the cooling system 60 of the first group G1 shown in FIGS. 2 and 3.

[0056] The cooling system 60 is a liquid cooling type with higher cooling capacity than the air cooling type. The cooling system 60 has a cooling circuit 62 having one radiator 66 and three pumps (first pump 68a to third pump 68c) in a pipe 64 through which a refrigerant flows. The cooling circuit 62 is a closed circuit. The refrigerant is a liquid.

[0057] The pipe 64 has three parallel pipes 70a, 70b, 70c connected in parallel to each other, and a common pipe 72 communicating the upstream side and the downstream side of each parallel pipe 70a, 70b, 70c. The radiator 66 is provided in the common pipe 72.

[0058] The parallel pipe 70a is arranged to cool the component group 24Ra corresponding to the VTOL rotor 20Ra, for example, the electric motor 26 and the inverter 28. The parallel pipe 70a may be arranged to cool other electrical components of the component group 24Ra. In the parallel pipe 70a, the first pump 68a is provided upstream of the component group 24Ra.

[0059] The parallel pipe 70b is arranged to cool the component group 24Ld corresponding to the VTOL rotor 20Ld, for example, the electric motor 26 and the inverter 28. The parallel pipe 70b may be arranged to cool other electrical components of the component group 24Ld. In the parallel pipe 70b, a second pump 68b is provided upstream of the component group 24Ld.

[0060] The parallel pipe 70c is arranged to cool the component group 24R1 corresponding to the cruise rotor 22R, for example, the electric motor 26 and the inverter 28. The parallel pipe 70c may be arranged to cool other electrical components of the component group 24R1. In the parallel pipe 70c, a third pump 68c is provided upstream of the component group 24R1.

[0061] In the cooling circuit 62 shown in FIG. 9, pumps (the first pump 68a to the third pump 68c) are provided in the respective parallel pipes 70a, 70b, and 70c. Instead of this, a common pump may be provided in the common pipe 72.

[0062] As shown in FIG. 5, during the takeoff to cruise of the aircraft 10 (time point t1 to time point t3) and during the cruise (after time point t3), the maximum value of the third transition 54 has no significant difference from the maximum values of the first transition 50 and the second transition 52. This means that the maximum value of the fourth transition 56 has no significant difference from the maximum heat generation amounts of the two component groups 24 corresponding to the two VTOL rotors 20 and the maximum heat generation amount of the one component group 24 corresponding to the one cruise rotor 22. That is, one cooling circuit 62 can be shared by the two component groups 24 corresponding to the two paired VTOL rotors 20 and the one component group 24 corresponding to the one cruise rotor 22. Therefore, in the present embodiment, the two component groups 24 corresponding to the two paired VTOL rotors 20 and the one component group 24 corresponding to the one cruise rotor 22 are collectively cooled by the same cooling circuit 62. Further, the battery 32a may be cooled by the cooling circuit 62.

[0063] [Operation of Cooling System 60] The operation of the cooling system 60 will be described with reference to FIG. 9. When the first pump 68a operates, the refrigerant circulates through the parallel pipes 70a and the common pipe 72. When the second pump 68b operates, the refrigerant circulates through the parallel pipes 70b and the common pipe 72. When the third pump 68c operates, the refrigerant circulates through the parallel pipes 70c and the common pipe 72. The refrigerant absorbs heat from each electrical component of each component group 24 and releases the heat at the radiator 66. In this way, each electrical component is cooled.

[0064] As described in [4.3] above, within the same group, the deviation in the distance between the two component groups 24 is small. Therefore, the deviation in the lengths of the parallel pipes 70a, 70b, and 70c within the same group is small. Therefore, by arranging the radiator 66 at an appropriate position, the difference in the pressure loss of the refrigerant flowing through the parallel pipes 70a, 70b, and 70c can be reduced, and the Discharge difference in the lift of the first pump 68a to the third pump 68c can be reduced.

[0065] [8 Other Embodiments] In the above embodiment, the power supply system 23 and the cooling system 60 have been described by taking the aircraft 10 having eight VTOL rotors 20 and two cruise rotors 22 as an example. However, the power supply system 23 and the cooling system 60 can also be provided in other aircraft 10 having different numbers of rotors. For example, the power supply system 23 and the cooling system 60 can also be provided in an aircraft 10 having two or more VTOL rotors 20. In that case as well, it is also possible to group two component groups 24 corresponding to two paired VTOL rotors 20 and one battery 32 into the same group. Further, when the aircraft 10 has a cruise rotor 22, it is also possible to group one or more component groups 24 corresponding to one or more VTOL rotors 20, the component group 24 corresponding to the cruise rotor 22, and one battery 32 into the same group.

[0066] The power supply system 23 may be a circuit other than the circuits shown in FIGS. 3 and 8. In short, as long as the respective component groups 24 are combined in the combination as described above, the circuit of the power supply system 23 does not matter.

[0067] In addition, the present invention is applicable not only to a hybrid aircraft having the engine 44 and the motor generator 42 but also to an electric aircraft not having the engine 44 and the motor generator 42. As an example, in the circuits shown in FIGS. 3 and 8, the configuration of the second smoothing capacitor 38 to the engine 44 may not be provided. In this case, by switching each switch 36 as necessary, it becomes possible to supply power from a certain group of batteries 32 to another group. As another example, in the circuits shown in FIGS. 3 and 8, in addition to the configuration of the second smoothing capacitor 38 to the engine 44, the switches 36 of each group may not be provided. In this case, each group is insulated from each other.

[0068] The power supply system 23 and the cooling system 60 of the above embodiment may be provided for the aircraft 10 having a tilt rotor.

[0069] [Technical idea obtained from the embodiment] The technical idea that can be grasped from the above embodiment will be described below.

[0070] Aspects of the present invention are a rotor (VTOL rotor 20, cruise rotor 22) that generates at least one of lift and thrust of the aircraft 10, a component group 24 composed of a plurality of electrical components that rotate the rotor, a plurality of the above Electrical component a cooling circuit 62 that cools, a cooling system 60 including having a plurality of the component groups 24 corresponding to a plurality of the rotors, the plurality of the component groups 24 are cooled by the same cooling circuit 62.

[0071] According to the above configuration, since a plurality of component groups 24 are cooled by the same cooling circuit 62, it is not necessary to provide a cooling circuit 62 for each component group 24 individually. That is, according to the above configuration, since components (such as pipes 64 and radiator 66) of the cooling circuit 62 are shared by a plurality of component groups 24, the number of components of the cooling system 60 provided in the aircraft 10 can be reduced. As a result, the cooling system 60 provided in the aircraft 10 becomes simpler and lighter.

[0072] In an aspect of the present invention, as the rotor, there are a VTOL rotor 20 that generates lift during vertical movement of the aircraft 10 and a cruise rotor 22 that generates thrust during horizontal movement of the aircraft 10, as the component group 24, there are a VTOL component group (for example, component group 24Ra) corresponding to the VTOL rotor 20 and a cruise component group (for example, component group 24R1) corresponding to the cruise rotor 22, the VTOL component group and the cruise component group may be cooled by the same cooling circuit 62.

[0073] The VTOL rotor 20 is mainly used during vertical takeoff and vertical landing. On the other hand, the cruise rotor 22 is mainly used during cruising. For this reason, the maximum value of the sum of the first input power of the component group 24 corresponding to the VTOL rotor 20 and the second input power of the component group 24 corresponding to the cruise rotor 22 does not have a large difference compared with the maximum value of the first input power and the maximum value of the second input power. Therefore, even if the battery 32 is shared by the component group 24 corresponding to the VTOL rotor 20 and the component group 24 corresponding to the cruise rotor 22, a large capacity is not required for the battery 32. For these reasons, from the viewpoints of circuit simplification and miniaturization of the battery 32, the combination of the component group 24 corresponding to the VTOL rotor 20, the component group 24 corresponding to the cruise rotor 22, and the battery 32 is appropriate.

[0074] The input power of the component group 24 corresponds to the heat generation amount of the component group 24. Therefore, even if the cooling circuit 62 is shared by the component group 24 corresponding to the VTOL rotor 20 and the component group 24 corresponding to the cruise rotor 22, a large cooling capacity is not required for the cooling circuit 62. From the perspective of simplifying and miniaturizing the cooling circuit 62, the combination of the component group 24 corresponding to the VTOL rotor 20, the component group 24 corresponding to the cruise rotor 22, and the battery 32 is appropriate.

[0075] In an aspect of the present invention, as the rotor, it has two VTOL rotors 20 that generate lift during vertical movement of the aircraft 10 and cancel each other's reaction forces, as the component group 24, it has two VTOL component groups (for example, component groups 24Ra and 24Ld) corresponding to the two VTOL rotors 20, the two VTOL component groups may be cooled by the same cooling circuit 62.

[0076] When one of the two VTOL rotors 20 that cancel each other's reaction forces stops due to a failure or the like, it is necessary to stop the other VTOL rotor 20 as well. That is, the two VTOL rotors 20 that cancel each other's reaction forces always operate together. From the perspective of efficiently cooling the electrical components, the combination of the two component groups 24 corresponding to the two VTOL rotors 20 that cancel each other's reaction forces and the battery 32 is appropriate.

[0077] In an aspect of the present invention, As the rotor, there are two first VTOL rotors (for example, VTOL rotors 20Ra and 20Ld) that generate lift and cancel out the reaction forces with each other during the vertical movement of the aircraft 10, and two second VTOL rotors (for example, VTOL rotors 20La and 20Rd), and a first cruise rotor (for example, cruise rotor 22R) and a second cruise rotor (for example, cruise rotor 22L) that generate thrust during the horizontal movement of the aircraft 10. As the component groups, there are two first VTOL component groups (for example, component groups 24Ra and 24Ld) corresponding to the two first VTOL rotors, two second VTOL component groups (for example, component groups 24La and 24Rd) corresponding to the two second VTOL rotors, a first cruise component group (for example, component group 24R1) corresponding to the first cruise rotor, and a second cruise component group (for example, component group 24L1) corresponding to the second cruise rotor. As the cooling circuit 62, there are a first cooling circuit and a second cooling circuit. The two first VTOL component groups and the first cruise component group may be cooled by the first cooling circuit, and the two second VTOL component groups and the second cruise component group may be cooled by the second cooling circuit.

[0078] As described above, from the viewpoints of simplification and miniaturization of the cooling circuit 62, the combination of the component group 24 corresponding to the VTOL rotor 20, the component group 24 corresponding to the cruise rotor 22, and the battery 32 is appropriate. Also, from the viewpoint of efficiently cooling the electrical components, the combination of the two component groups 24 corresponding to the two VTOL rotors 20 that cancel out the reaction forces and the battery 32 is appropriate.

[0079] In an aspect of the present invention, The difference (D1) between the length from one of the first VTOL rotors (e.g., VTOL rotor 20Ra) to the first cruise rotor (e.g., cruise rotor 22R) and the length from the other first VTOL rotor (e.g., VTOL rotor 20Ld) to the first cruise rotor (e.g., cruise rotor 22R) may be smaller than the difference (D2) between the length from one of the first VTOL rotors (e.g., VTOL rotor 20Ra) to the second cruise rotor (e.g., cruise rotor 22L) and the length from the other first VTOL rotor (e.g., VTOL rotor 20Ld) to the second cruise rotor (e.g., cruise rotor 22L).

[0080] According to the above configuration, there is little deviation in the distance between the two component groups 24 within the same group. Therefore, there is little deviation in the lengths of the parallel pipes 70a, 70b, and 70c within the same group. Accordingly, by appropriately arranging the radiator 66, the difference in the lift of the first pump 68a to the third pump 68c can be reduced.

[0081] In an aspect of the present invention, each of the component groups 24 may , Electricity have a drive circuit (inverter 28) of the drive motor 26.

[0082] In an aspect of the present invention, at least one of the component groups 24 may have a battery 32 that supplies power to the electric motor 26 via the drive circuit. The

[0083] In an aspect of the present invention, the cooling circuit 62 includes a pipe 64, a radiator 66, and a plurality of pumps (first pump 68a to third pump 68c), the pipe 64 includes a plurality of parallel pipes 70a, 70b, 70c connected in parallel to each other, and a common pipe 72 that communicates the upstream side and the downstream side of each of the parallel pipes 70a, 70b, 70c, ​The parallel pipes 70a, 70b, and 70c are provided in the same number as the component groups 24 and are arranged to cool the component groups 24. The pumps are provided in respective parallel pipes 70a, 70b, and 70c. The radiator 66 is provided in the common pipe 72. The discharge head of the pump may be determined according to the length of the circulation path formed by the parallel pipes 70a, 70b, 70c and the common pipe 72.

[0084] In an aspect of the present invention, The aircraft 10 may include wings (front wing 14, rear wing 16) that generate lift during forward movement.

[0085] Note that the cooling system according to the present invention is not limited to the above embodiment, and various configurations can be adopted without departing from the gist of the present invention.

Explanation of reference numerals

[0086] 10…Aircraft 14…Front wing (wing) 16…Rear wing (wing) 20, 20La~20L d , 20Ra~20Rd…VTOL rotor (rotor, first VTOL rotor, second VTOL rotor) 22, 22L, 22R…Cruise rotor (rotor, first cruise rotor, second cruise rotor) 24, 24L1, 24L2、 24La~24Ld, 24R1, 24R2、 24Ra~24Rd…Component group (VTOL component group, first VTOL component group, second VTOL component group, cruise component group, first cruise component group, second cruise component group) 26…Electric motor (electrical component) 28…Inverter (electrical component, drive circuit) 32, 32a~32d…Battery (electrical component) 60…Cooling system 62… Cooling circuit (first cooling circuit, second cooling circuit) 64… Pipe 66… Radiator 68a… First pump (pump) 68b… Second pump (pump) 68c… Third pump (pump) 70a… Parallel pipe 70b… Parallel pipe 70c… Parallel pipe 72… Common pipe

Claims

An aircraft comprising a cooling system having a cooling circuit for cooling a component group composed of a plurality of electrical components that rotate a rotor that generates at least one of lift and thrust, wherein the rotor is a VTOL rotor that generates lift during vertical movement and a cruise rotor that generates thrust during horizontal movement, the component group is a VTOL component group corresponding to the VTOL rotor and a cruise component group corresponding to the cruise rotor, and the VTOL component group and the cruise component group are cooled by the same cooling circuit. An aircraft comprising a cooling system having a cooling circuit for cooling a component group composed of a plurality of electrical components that rotate a rotor that generates lift, wherein the rotor is two VTOL rotors that generate lift during vertical movement and cancel out reaction forces with each other, the component group is two VTOL component groups corresponding to the two VTOL rotors, and the two VTOL component groups are cooled by the same cooling circuit. Claim 3 An aircraft comprising a cooling system having a cooling circuit for cooling a component group composed of a plurality of electrical components that rotate a rotor that generates at least one of lift and thrust of the aircraft, wherein the rotor is two first VTOL rotors and two second VTOL rotors that generate lift during vertical movement of the aircraft and cancel out reaction forces with each other, and a first cruise rotor and a second cruise rotor that generate thrust during horizontal movement of the aircraft, The component groups include two first VTOL component groups corresponding to the two first VTOL rotors, two second VTOL component groups corresponding to the two second VTOL rotors, a first cruise component group corresponding to the first cruise rotor, and a second cruise component group corresponding to the second cruise rotor. The cooling circuit includes a first cooling circuit and a second cooling circuit. The two first VTOL component groups and the first cruise component group are cooled by the first cooling circuit, and the two second VTOL component groups and the second cruise component group are cooled by the second cooling circuit. Aircraft.

4. An aircraft according to any one of claims 1 to 3, Each of the component groups has a drive circuit for an electric motor. Aircraft.

5. An aircraft according to claim 4, At least one of the component groups has a battery that supplies power to the electric motor via the drive circuit. Aircraft.

6. An aircraft according to any one of claims 1 to 5, The cooling circuit has pipes, a radiator, and a plurality of pumps. The pipes include a plurality of parallel pipes connected in parallel to each other, and a common pipe communicating the upstream side and the downstream side of each of the parallel pipes. The parallel pipes are provided in the same number as the component groups and are arranged to cool the component groups. The pumps are provided in each of the parallel pipes. The radiator is provided in the common pipe. The discharge head of the pump is determined according to the length of the circulation path composed of the parallel pipes and the common pipe. Aircraft.

7. An aircraft according to claim 1, The VTOL rotor has a rotation axis fixed along the vertical direction, and generates thrust in the axial direction of the rotation axis. The cruise rotor has a rotation axis fixed along the horizontal direction, and generates thrust in the axial direction of the rotation axis, an aircraft.

8. The aircraft according to claim 2, Each of the two VTOL rotors has a rotation axis fixed along the vertical direction, and generates thrust in the axial direction of the rotation axis, an aircraft.

9. The aircraft according to claim 3, Each of the two first VTOL rotors and the two second VTOL rotors has a rotation axis fixed along the vertical direction, and generates thrust in the axial direction of the rotation axis, Each of the first cruise rotor and the second cruise rotor has a rotation axis fixed along the vertical direction, and generates thrust in the axial direction of the rotation axis, an aircraft.

10. The aircraft according to any one of claims 1 to 9, An aircraft comprising wings that generate lift during forward movement.

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