flying object

Abstract

We provide technology to achieve weight reduction for aircraft. [Solution] According to one aspect of the present invention, an aircraft is provided, comprising a motor, a support, and an inverter, wherein the motor is configured to generate rotational power for rotating the rotor blades of the aircraft, the support has a first position and a second position, the first position being a position for rotatably fixing the rotation axis of the rotor blades, the second position being a position different from the first position through which an airflow passes, the airflow including at least the airflow generated by the rotation of the rotor blades, and the inverter is configured to electrically control the rotation of the motor and is located at the second position.

Description

Technical Field

[0001] The present invention relates to a flying object.

Background Art

[0002] Patent Document 1 discloses an aircraft cooling system capable of cooling a heat generating part.

[0003] This aircraft cooling system includes a rotor capable of generating thrust in the vertical direction, a heat generating part arranged below the rotor, a support part (boom) for supporting the heat generating part, a structure (second fairing) protruding from the support part toward the rotor, and a heat exchanger (surface heat exchanger) provided in the structure. The refrigerant heated by the heat generating part is introduced into an inlet (fairing inlet) provided in the surface heat exchanger, and the refrigerant cooled by the surface heat exchanger is supplied from an outlet (fairing outlet) provided in the surface heat exchanger to the heat generating part.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In the prior art, there is a problem that an internal fan is required to cool an inverter and a refrigerant and its passage are required to cool a heat generating part, resulting in an increase in the weight of the flying object.

[0006] In view of the above circumstances, the present invention aims to provide a technology for realizing weight reduction of a flying object.

Means for Solving the Problems

[0007] According to one aspect of the present invention, an aircraft is provided comprising a motor, a support, and an inverter, wherein the motor is configured to generate rotational power for rotating the rotor blades of the aircraft, the support has a first position and a second position, the first position being a position for rotatably fixing the rotation axis of the rotor blades, the second position being a position different from the first position through which an airflow passes, the airflow including at least the airflow generated by the rotation of the rotor blades, and the inverter is configured to electrically control the rotation of the motor and is located at the second position.

[0008] According to this disclosure, the inverter can be cooled by airflow. As a result, the thermal mass of the inverter can be reduced, and a dedicated cooling fan for the inverter is not required, which enables a lighter aircraft. [Brief explanation of the drawing]

[0009] [Figure 1] This is an external view diagram showing the configuration of drone 11. [Figure 2] This is a block diagram showing the electrical hardware configuration of drone 11. [Figure 3] This is an external view showing an example of the configuration and positional relationship of the support unit 3, rotor blade 4, and electric unit 5. [Figure 4] This diagram illustrates an example of the configuration of the heatsink 53a of the inverter 53. [Figure 5] This diagram illustrates an example of the configuration of the heatsink 53a of the inverter 53. [Figure 6] This is an external view showing an example of the configuration and positional relationship of the support unit 3, rotor blade 4, and electric unit 5. [Figure 7] This is an external view showing an example of the configuration and positional relationship of the support unit 3, rotor blade 4, and electric unit 5. [Modes for carrying out the invention]

[0010] Hereinafter, an example of an embodiment of the present invention will be described with reference to the figures. The various features shown in the embodiments below can be combined with each other.

[0011] (Flying object 1) First, an overview of the aircraft 1 will be described. In one embodiment, a drone 11 is used as an example of the aircraft 1.

[0012] Figure 1 is an external view showing the configuration of the drone 11. Figure 2 is a block diagram showing the electrical hardware configuration of the drone 11. Figure 3 is an external view showing an example of the configuration and positional relationship of the support unit 3, rotor blade 4, and electric unit 5. Figure 4 is a diagram illustrating an example of the configuration of the heat sink 53a of the inverter 53.

[0013] As shown in Figures 1 and 2, an example of a flying object 1, a drone 11, comprises a body 2, a support unit 3, rotor blades 4, an electric motor unit 5, a microcontroller 6, a sensor 7, and an imaging unit 8. The drone 11 can fly by freely rotating its multiple rotor blades 4, ascending and descending, moving forward and backward, or rotating.

[0014] (Aircraft 2) As shown in Figure 1, the body 2 is the fuselage of the drone 11. The body 2 is hollow and contains an electric unit 5, a microcontroller 6, a sensor 7, and an imaging unit 8. The shape of the body 2 is preferably a cylinder or a prism such as a triangular prism or a rectangular prism, but is not limited as long as the drone 11 can fly stably. The material of the body 2 may be a metal such as aluminum or maglucium alloy, or a non-ferrous metal such as plastic or carbon fiber reinforced plastic. The material of the body 2 is preferably lightweight and has high strength and rigidity. The size of the body 2 can be appropriately selected depending on the specifications of the drone 11, such as the flight speed, the number, weight, size, shape, packaging, and contents of the cargo to be transported.

[0015] (Support part 3) As shown in FIG. 1, a plurality of support portions 3 are connected to the airframe 2. Specifically, in the drone 11, four rod-shaped support portions 3 are connected to the airframe 2. One end of the support portion 3 is connected to the airframe 2, and the other end is engaged with at least one rotary wing 4 so that the rotary wing 4 can rotate. A transmission cable (not shown) is wired inside or outside the support portion 3. Further, the support portion 3 has a first position P1 and a second position P2. Details of the first position P1 and the second position P2 will be described later. Note that the shape, material, and size of the support portion 3 are not limited, similar to the airframe 2. The airframe 2 and the support portion 3 may be an integral structure, or may be connected as separate parts.

[0016] (Rotary wing 4) As shown in FIG. 3, the rotary wing 4 includes a hub 41, blades 42 joined to the hub 41, and a rotating shaft 43. The hub 41 is fitted with the rotating shaft 43 and rotates by the power from the motor 52 via the rotating shaft 43. When the blades 42 rotate, an air flow AF is generated in the direction along the rotating shaft 43. In FIG. 3, the air flow AF is generated from top to bottom in the figure. Thereby, a propulsive force for propelling the drone 11 is generated. In other words, the air flow AF includes at least the flow of air generated by the rotation of the rotary wing 4. In this way, the rotary wing 4 converts the rotational force output from the motor 52 into a propulsive force in order to propel the drone 11. Note that the number of blades 42 may be plural. Also, the number of rotary wings 4 is not limited as long as it is three or more. As shown in FIG. 1, specifically, the drone 11 includes four support portions 3, each support portion 3 includes two rotary wings 4, and each rotary wing 4 includes two blades 42. That is, the drone 11 which is the flying object 1 is of a multi-copter type.

[0017] The rotating shaft 43 of the rotary wing 4 is arranged based on the first position P1 of the support portion 3. Specifically, as shown in FIG. 3, the rotating shaft 43 of the rotary wing 4 is arranged such that the rotation center O of the rotating shaft 43 passes through the first position P1 of the support portion 3. In other words, the first position P1 is a position for rotatably fixing the rotating shaft 43 of the rotary wing 4.

[0018] The rotary wings 4 can all rotate in the same direction and can also rotate independently. The rotary wings 4 are controlled by a control unit 63 described later, that is, a flight controller, so that the rotation direction and rotation speed of the electric unit 5 are controlled, and the drone 11 can ascend and descend, move forward and backward, or rotate.

[0019] (Electric unit 5) The electric unit 5 constitutes the electric and electronic devices that drive the drone 11. As shown in FIGS. 1 and 2, specifically, the electric unit 5 includes a battery 51, a motor 52, an inverter 53, and a case 54, and is mechanically connected to the airframe 2 and the support portion 3. That is, the drone 11, which is an example of the flying object 1, includes a motor 52, an inverter 53, and a case 54.

[0020] The battery 51 is the power source of the drone 11 and is a rechargeable secondary battery. As such a battery, for example, a lead storage battery, a NAS battery, a nickel-hydrogen battery, a lithium-ion battery, etc. may be appropriately adopted.

[0021] The motor 52 is electrically connected to the battery 51 via the inverter 53. The motor 52 converts the electrical energy output from the battery 51 into mechanical energy and rotates the rotary wings 4. That is, the motor 52 is configured to generate rotational power for rotating the rotary wings 4 of the flying object 1.

[0022] As shown in FIG. 3, the motor 52 is disposed at the end of the support portion 3 and includes a motor shaft 52a. By attaching a bearing (not shown) to the motor shaft 52a, the motor shaft 52a can rotate with the bearing. As shown in FIG. 3, the motor shaft 52a of the motor 52 and the rotation shaft 43 of the rotary wing 4 may be constituted by one shaft. Note that the motor shaft 52a of the motor 52 is not limited as long as it can transmit the rotational power generated by the motor 52 to the rotary wing 4. For example, it may be configured such that rotational power can be transmitted from the motor shaft 52a to the rotation shaft 43 via a speed reducer (not shown) or the like.

[0023] When the motor shaft 52a of the motor 52 and the rotation shaft 43 of the rotor blade 4 are connected by a single shaft, as shown in Figure 3, the motor shaft 52a of the motor 52 is positioned such that its rotation center O passes through the first position P1 of the support part 3. In this case, the first position P1 is the position that rotatably fixes the rotation shaft 43 of the rotor blade 4 and the motor shaft 52a of the motor 52. The type of motor 52 is not limited as long as it can be controlled by the inverter 53, but for example, an AC motor (induction motor, synchronous motor, etc.) or a brushless DC motor (direct current motor) is preferred.

[0024] The inverter 53 controls the rotation of the motor 52 in response to instructions from the control unit 63 of the microcontroller 6. In other words, the inverter 53 is configured to electrically control the rotation of the motor 52. Specifically, the inverter 53 converts direct current (DC) power from the battery 51 to alternating current (AC), and further adjusts the frequency and voltage to control the rotational speed and torque of the motor 52. Instructions to the inverter 53 may be executed by a program stored in the memory unit 62, or by a program transmitted by the user from an external source to the communication unit 61. Any control method can be applied in this case, specifically, for example, a VVVF inverter (Variable Voltage Variable Frequency Inverter) or a CVVF inverter (Constant Voltage Variable Frequency Inverter).

[0025] As shown in Figure 3, the inverter 53 is positioned at a second position P2 of the support section 3. In this case, the second position P2 is different from the first position P1 and is a position through which the airflow AF passes. With this configuration, the inverter 53 can be cooled by the airflow AF. As a result, the thermal mass of the inverter 53 can be reduced, and a dedicated cooling fan for the inverter 53 is not required, making it possible to lighten the aircraft 1. Furthermore, the reduction in weight makes it possible to extend the flight distance and time per unit output of the motor 52. In the case of a multicopter type aircraft 1, since it is equipped with multiple rotors 4, motors 52 and inverters 53, the effect of this weight reduction can be obtained even more.

[0026] Furthermore, as shown in Figure 4, the inverter 53 has a heat sink 53a that dissipates the heat generated by the inverter 53. Specifically, as shown in Figure 3, the heat sink 53a is positioned opposite the blade 42 in the direction along the rotation axis 43 of the rotor blade 4. More specifically, the heat sink 53a is positioned opposite a portion of the circle formed by the rotation of the blade 42. As a result, the airflow AF generated from top to bottom in Figure 3 by the rotation of the blade 42 of the rotor blade 4 passes through the heat sink 53a.

[0027] Furthermore, as shown in Figure 4, the heat sink 53a has a plurality of fins 53b. Each fin 53b is substantially plate-shaped, and the plurality of fins 53b are arranged at predetermined intervals so as to protrude outward from the surface of the inverter 53.

[0028] Furthermore, the multiple fins 53b are arranged along a predetermined direction. In the multiple fins 53b shown in Figure 4, the longitudinal direction of each fin 53b is arranged along a first direction D1, which is an example of a predetermined direction. In this case, all the fins 53b face the circle formed by the rotation of the blade 42. As a result, an airflow path AP is formed between each fin 53b in the heat sink 53a. In other words, the airflow path AP is formed along the first direction D1. In this case, the first direction D1 is the longitudinal direction of the support part 3 and the radial direction of the circle formed by the rotation of the blade 42. Also, in this case, the airflow AF first flows downward from the position of the blade 42 of the rotor 4 in Figure 3. Then, it changes direction at the position of the heat sink 53a (fins 53b) and flows along the first direction D1, which is the longitudinal direction of the fins 53b, passing between each fin 53b. In other words, the multiple fins 53b are arranged so that an airflow AF passes between each fin 53b. With this configuration, heat exchange can be efficiently performed by the heat sink 53a, and as a result, the inverter 53 can be further cooled.

[0029] As shown in Figure 3, the case 54 is box-shaped and configured to house at least a portion of the motor 52 and inverter 53. In other words, the motor 52 and inverter 53 are supported by the support section 3 via the case 54. With this configuration, the motor 52 and inverter 53 can be miniaturized by integrating them. As a result, the drone 11, which is the flying body 1, can be made even lighter.

[0030] (Microcontroller 6) The microcontroller 6 controls the flight and overall operation of the drone 11. As shown in Figure 2, the microcontroller 6 is configured to control the operation of the rotor blades 4 via the inverter 53 of the electric unit 5. The microcontroller 6 has a communication unit 61, a memory unit 62, and a control unit 63, and these components are electrically connected inside the drone 11 via a communication bus 60. Each component will be described in more detail below.

[0031] The communication unit 61 is configured to transmit various electrical signals from the microcontroller 6 to external components. The communication unit 61 is also configured to receive various electrical signals from external components to the microcontroller 6. More preferably, the communication unit 61 has a network communication function, enabling the communication of various information between the drone 11 and external devices via a network such as the Internet.

[0032] The memory unit 62 stores various types of information as defined above. This can be done, for example, as a storage device such as a solid-state drive (SSD), or as memory such as random access memory (RAM) that stores temporarily necessary information (arguments, arrays, etc.) related to program calculations. A combination of these may also be used. The memory unit 62 stores various programs and variables related to the operation of the drone 11 executed by the control unit 63.

[0033] The control unit 63 performs control such as attitude control of the drone 11. The control unit 63 is, for example, a central processing unit (CPU) not shown. The control unit 63 realizes various functions related to the drone 11 by reading predetermined programs stored in the control unit 63. Here, the control unit 63 may be implemented as a single control unit 63, or as multiple control units 63 for each function, or a combination thereof.

[0034] (camera7) Sensor 7 detects physical quantities such as light and pressure during flight and converts them into analog electrical signals. These analog electrical signals are converted into digital electrical signals by an analog-to-digital (A / D) converter (not shown) and used as input data for control purposes such as attitude control of the drone 11.

[0035] Specifically, sensor 7 is a device that detects physical quantities such as a gyro sensor (not shown) for detecting the angle of the aircraft 2, an accelerometer (not shown) for detecting the acceleration of the drone 11, a geomagnetic sensor (not shown) for detecting direction, an ultrasonic sensor for detecting obstacles, or an infrared sensor, and converts them into analog electrical signals. Furthermore, sensor 7 may also include a GNSS (Global Navigation Satellite System) receiver that receives radio waves from satellites to measure the position of the drone 11 on Earth.

[0036] (Imaging Unit 8) The imaging unit 8 captures images of the ground surface where the drone 11 is flying. The imaging unit 8 may be used when GNSS signals, which are used to detect forward, backward, left, and right movement, cannot be received. Specifically, when GNSS signals cannot be received, the drone 11 measures the amount of movement by observing changes in the images captured by the imaging unit 8 and detects forward, backward, left, and right movement. The images captured by the imaging unit 8 are stored in the storage unit 62.

[0037] The imaging unit 8 is an optical device for capturing images, either built into or attached to the drone 11. Specifically, the imaging unit 8 includes, for example, a CCD (Charge Couple Devices) image sensor or a CMOS (Completely Metal Oxide Semiconductor) image sensor, which is an image sensor. The image sensor is an electronic component that converts light entering through the lens of the imaging unit 8 into an electrical signal. The number, size, and other technical specifications of the image sensors in the imaging unit 8 are not limited.

[0038] [others] An aircraft 1 according to one embodiment may be implemented in the following manner.

[0039] Figure 5 is a diagram illustrating an example of the configuration of the heat sink 53a of the inverter 53.

[0040] In the embodiment shown in Figure 4, an example was described in which, in the heat sink 53a, a plurality of fins 53b are arranged with the longitudinal direction of each fin 53b along the first direction D1, thereby forming an airflow path AP in a direction along the first direction D1. However, the invention is not limited to this. As shown in Figure 5, for example, in the heat sink 53a, a first airflow path AP1 and a second airflow path AP2 may be formed as airflow paths AP by arranging a plurality of fins 53b. In this case, the first airflow path AP1 is an airflow path AP formed in a direction along the first direction D1, and the second airflow path AP2 is an airflow path AP formed in a direction along the second direction D2, which is a direction intersecting the first direction D1. The second airflow path AP2 is formed so that air generated by the flight and movement of the drone 11 can pass through it. In other words, the airflow AF in this case includes the airflow AFa generated by the rotation of the rotor blade 4 and the airflow AFb generated by the flight and movement of the flying body 1, which is the drone 11. With this configuration, the inverter 53 can be further cooled.

[0041] Figure 6 is an external view showing an example of the configuration and positional relationship of the support unit 3, rotor blade 4, and electric unit 5.

[0042] In the embodiment shown in Figure 5, the first airflow path AP1 and the second airflow path AP2, formed by the arrangement of multiple fins 53b, are described as being formed at positions opposite the blade 42, but the invention is not limited to this. As shown in Figure 6, for example, the multiple fins 53b may be arranged to protrude outward from the surface of the inverter 53 along the direction of the airflow AFb generated by the flight and movement of the drone 11. In this case, the airflow AFa generated by the rotation of the rotor blade 4 mainly passes through the second airflow path AP2. In this case, the airflow AF includes the airflow AFa generated by the rotation of the rotor blade 4 and the airflow AFb generated by the flight and movement of the aircraft 1, which is the drone 11. With such a configuration, the inverter 53 can be further cooled.

[0043] Figure 7 is an external view showing an example of the configuration and positional relationship of the support unit 3, rotor blade 4, and electric unit 5.

[0044] In the embodiment shown in Figure 3, the motor 52 and inverter 53 are integrated by being housed in a case 54, but the invention is not limited to this. For example, the motor 52 and inverter 53 may be configured as separate components. Specifically, as shown in Figure 7, the inverter 53 may be located at a distance from the motor 52 and at the second position P2 of the support portion 3. In this case, the inverter 53 is positioned so that the circular shape formed by the rotation of the blade 42 faces the fin 53b. As a result, the inverter 53 is cooled by the airflow AF, which is the airflow AFa generated by the rotation of the rotor blade 4. With this configuration, the inverter 53 can be cooled by the airflow AF while maintaining design flexibility.

[0045] The aircraft 1 is not limited to a drone 11, but may be any unmanned aircraft, or even a manned aircraft. In other words, the aircraft 1 may be a manned or unmanned aircraft. With this configuration, it is possible to provide a technology relating to a manned or unmanned aircraft capable of cooling the inverter 53 by airflow AF.

[0046] Furthermore, they may be provided in the following embodiments.

[0047] (1) An aircraft comprising a motor, a support, and an inverter, wherein the motor is configured to generate rotational power for rotating the rotor blades of the aircraft, the support has a first position and a second position, the first position being a position for rotatably fixing the rotation axis of the rotor blades, and the second position being a position different from the first position through which an airflow passes, wherein the airflow includes at least the airflow generated by the rotation of the rotor blades, and the inverter is configured to electrically control the rotation of the motor and is located at the second position.

[0048] With this configuration, the inverter can be cooled by airflow. As a result, the thermal mass of the inverter can be reduced, and a dedicated cooling fan for the inverter is not required, allowing for a lighter aircraft. Furthermore, this weight reduction makes it possible to extend the flight distance and time per unit of motor output. In the case of multi-rotor aircraft, which are equipped with multiple rotors, motors, and inverters, the effects of this weight reduction can be realized even more.

[0049] (2) The aircraft described in (1) above, wherein the airflow includes the airflow generated by the rotation of the rotor blades and the airflow generated by the aircraft flying and moving.

[0050] This configuration allows for further cooling of the inverter.

[0051] (3) The aircraft described in (1) or (2) above, wherein the inverter has a heat sink for dissipating heat generated by the inverter, the heat sink has a plurality of fins, and the plurality of fins are arranged so that the airflow passes between each of the fins.

[0052] With this configuration, heat exchange can be efficiently performed by the heat sink, and as a result, the inverter can be further cooled.

[0053] (4) An aircraft according to any one of (1) to (3) above, further comprising a case, wherein the case is configured to house at least a portion of the motor and the inverter, and the motor and the inverter are supported by the support portion via the case.

[0054] This configuration allows for miniaturization by integrating the motor and inverter. As a result, the aircraft can be made even lighter.

[0055] (5) In any one of the above (1) to (4), the aircraft is either a manned aircraft or an unmanned aircraft.

[0056] This configuration provides technology for a manned or unmanned aircraft capable of cooling the inverter by airflow. Of course, this is not always the case.

[0057] Finally, while various embodiments of the present invention have been described, these are presented as examples only and are not intended to limit the scope of the invention. These novel embodiments can be implemented in a variety of other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their variations are included in the scope and spirit of the invention, as well as in the claims and their equivalents. [Explanation of symbols]

[0058] 1: Flying object 11: Drone 2: Aircraft 3: Support part 4: Rotary blades 41: Hub 42: Blade 43: Rotation axis 5: Electric Unit 51: Battery 52: Motor 52a: Motor shaft 53: Inverter 53a: Heatsink 53b: Finn 54: Case 6: Microcontroller 60: Communications bus 61: Communications Department 62: Storage section 63: Control Unit 7: Sensor 8: Imaging Unit AF: Airflow AFa: Airflow AFb: Airflow AP: Airflow channel AP1: First airflow channel AP2: Second airflow channel D1: First direction D2: Second direction O: Center of rotation P1: First position P2: Second position

Claims

1. It is an flying object, It comprises a motor, a support unit, and an inverter. The motor is configured to generate rotational power to rotate the rotor blades of the aircraft, The support portion has a first position and a second position, The first position is a position in which the rotation axis of the rotor blade is fixed so as to be rotatable, The second position is a position through which the airflow passes, which is different from the first position, and the airflow includes at least the airflow generated by the rotation of the rotor blade. The aforementioned inverter is The rotation of the aforementioned motor is electrically controlled, An aircraft positioned at the second location.

2. In the flying vehicle according to claim 1, The airflow includes the airflow generated by the rotation of the rotor blades and the airflow generated by the flight and movement of the aircraft.

3. In the flying vehicle according to claim 1, The inverter has a heat sink for dissipating the heat generated by the inverter. The heat sink has a plurality of fins, An aircraft having a plurality of fins arranged such that the airflow passes between each of the fins.

4. In the flying vehicle according to claim 1, With additional cases, The case is configured to house at least a portion of the motor and the inverter, The motor and the inverter are supported by the support portion via the case in the flying body.

5. In the aircraft according to any one of claims 1 to 4, The aforementioned aircraft is either a manned or unmanned aircraft.

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