JP6913980B2 - Aircraft and frame of air vehicle - Google Patents

Description

The present invention relates to a flying object represented by what is generally called a drone and a frame of the flying object, and particularly to a cooling structure using the frame.

Aircraft with multiple propellers called drones, especially unmanned aerial vehicles, are being applied in the industrial field. Agricultural drones that spray pesticides and chemicals such as liquid fertilizer on fields are one of the fields of application.

Assuming that industrial drones will be used under various environmental conditions, the propeller's rotary drive motor, its drive and control circuits, the battery that is the drive power source, and other components are waterproof and dustproof. It is placed in a closed space. Therefore, the heat generated from the components such as the motor is trapped in the closed space and the temperature rises, so that the components are easily overheated.

Industrial drones such as agricultural drones carry luggage such as chemicals, so relatively large drones are used so that they can generate thrust that can withstand the load of the luggage, and the load of the luggage is added to this. Therefore, the weight becomes heavy. Heavy drones are speed limited for safety reasons and fly at low speeds. A drone that flies at a low speed has a poor air-cooling effect, and if it has a structure in which the temperature of components tends to rise like the industrial drone, it is necessary to devise a cooling method.

Patent Document 1 describes a cooling system for an air vehicle. In this cooling system, a heat sink is provided on the heat radiating surface to be heat-controlled to promote heat dissipation, and it is not intended for a drone.

In the drone, it is conceivable to provide a heat sink and fins for cooling, and to use a heat exhaust duct, a diffuser, and the like. However, if the above-mentioned parts are added for cooling, the weight of the drone will increase and the structure will become complicated. It is desirable that the original structure of the drone itself has a structure suitable for promoting heat dissipation.

In addition, it would be ideal if the frame structure of the drone has heat dissipation and vibration damping properties, and it is possible to achieve both weight reduction and strength assurance, and to stabilize the attitude during flight.

Patent Document 2 and Patent Document 3 are documents that disclose techniques related to the problem to be solved by the present invention or related to the constitution of the present invention.

The invention described in Patent Document 2 relates to a flight safety frame for a drone, and the wall frame, the cross beam, and the support legs are all made of fiber reinforced plastic pipe material. The safety frame is added to the drone's airframe to ensure the safety of the drone itself and the object in the event of contact with the drone. Therefore, there is a drone aircraft in addition to the safety frame.

The invention described in Patent Document 3 has an object to be solved in an unmanned airframe, to reduce the vibration from the airframe in flight toward the measuring device. Specifically, it has a pair of support frames that support the laser scanner that constitutes the measurement unit, and a pair of connecting frames that connect the pair of support frames to each other and attach them to the flight unit. A plate made of fiber reinforced resin having different rigidity is interposed between the laser scanner and the support frame, and between the support frame and the connecting frame.

JP-A-2010-208488 Japanese Patent No. 62455666 Japanese Unexamined Patent Publication No. 2017-193251

The cooling system described in Patent Document 1 does not assume an air vehicle such as a drone having a plurality of propeller drive motors for individually rotating and driving a plurality of propellers, and is not applicable to a drone cooling system. Can not.

Patent Document 2 and Patent Document 3 do not describe a structure for dissipating heat generated from a heat generating component of an air vehicle.

An object of the present invention is to obtain an air vehicle and a frame of the air vehicle that do not require additional parts for heat radiation by making the structure of the air vehicle itself suitable for heat dissipation.

The present invention
An air vehicle having a plurality of propeller drive motors for individually rotating and driving a plurality of propellers.
A frame formed by combining a plurality of support arms that support the plurality of propeller drive motors,
A built-in component support that is composed of a thermal conductor and supports internal components including heat-generating components and is coupled to the frame.
The most important feature is to have.

According to the present invention, the heat generated by the heat-generating component is transmitted to the built-in component support made of a heat conductor to dissipate heat, and further transmitted to the frame to dissipate heat, so that the heat dissipation effect is high and the built-in component is protected from high heat. be able to.

It is a perspective view which shows the Example of the flying object which concerns on this invention. It is a top view of the said Example. It is a front view of the said Example. It is a right side view of the said Example. It is a bottom view of the said Example. It is a top view which shows the said Example in the state which the propeller is removed. It is a front view which shows the said Example in the state which the propeller is removed. It is a right side view which shows the said Example in the state which the propeller is removed. It is a perspective view which shows the main part of the said Example in an enlarged manner. The simulation results of the downward flow generated when each propeller is rotationally driven in the flying object are shown. A) is a diagram showing the simulation results of this embodiment, b) is a schematic diagram showing the above simulation results, c). Is a reference diagram showing the simulation results of the downward flow generated in the case of a one-stage propeller.

Hereinafter, embodiments of an air vehicle (hereinafter referred to as “drone”) according to the present invention will be described with reference to the drawings. All figures are illustrations. In addition, in this specification, a drone refers to a general vehicle body having a plurality of rotor blades or flight means regardless of a power system or a maneuvering system. As the power system, there are those using electric power and those using a prime mover such as an internal combustion engine. The maneuvering method includes wireless or wired, and autonomous flight type or manual maneuvering type.

[Overall drone configuration]
In FIGS. 1 to 5, the drone has four propellers 101-1a, 101-1b, 101-2a, 101-2b, 101-3a, 101-3b, 101-4a, 101-, which are also called rotors above and below. Has 4b. These propellers are a means for flying a drone, and are equipped with four sets of two-stage propellers, for a total of eight, in consideration of the balance between flight stability, aircraft size, and battery consumption. .. The centers of rotation of the four sets of propellers are located at the corners of the rectangle in plan view. The propellers 101-2a and 101-4a are on the front side in the direction of travel of the drone.

Each of the above propellers is a propeller drive motor (hereinafter, may be simply referred to as a "motor") 102-1a, 102-1b, 102-2a, 102-2b, 102-3a, 102-3b, 102-4a, 102-4b. It is driven to rotate individually. A set of upper and lower propellers, for example, 101-1a and 101-1b, have axes on the same straight line for the sake of drone flight stability, etc., and are in opposite directions by motors 102-1a and 102-1b. Is rotated to. The upper and lower propellers of each set are rotationally driven in opposite directions to generate a downward flow, and generate a thrust in the direction of raising the drone. The upper and lower propellers of the other sets are similarly configured and generate thrust in the same way.

The illustrated embodiment is an agricultural drone, which is provided with four drug nozzles 103-1, 103-2, 103-3, 103-4 for spraying the drug downward. As used herein, an agent generally refers to a liquid or powder applied to a field such as pesticides, herbicides, liquid fertilizers, pesticides, seeds, and water.

The drone has a drug tank 104 for accommodating the drug to be sprayed. The drug tank 104 is provided at a position close to the center of gravity of the drone and at a position lower than the center of gravity from the viewpoint of weight balance. A pump 106 is attached to the lower side of the medicine tank 104, and the pump 106 is connected to the medicine hose 105. The drug hose 105 extends linearly in the lower part of the front side in the traveling direction of the drone, straddling almost the entire width direction of the drone. Four drug nozzles 103-1, 103-2, 103-3, and 103-4 are arranged at regular intervals in the length direction of the drug hose 105. When the pump 106 operates, the medicine in the medicine tank 104 is discharged from each medicine nozzle and sprayed on the field.

[Frame composition]
Next, the structure of the drone frame and the structure of the built-in component support 50 according to the embodiment will be described in detail with reference to FIGS. 6 to 9. The frame of the drone is integrally connected to each other and is composed of a plurality of support arms that support the plurality of propeller drive motors. A frame composed of a plurality of support arms is composed of a pair of frames that are integrally connected to each other at predetermined intervals above and below.

The plurality of support arms constituting the upper frame include one first support arm 10 that supports the propeller drive motor at both ends, and two second support arms 11 and 12 extending from the first support arm 10. Must have. The second support arms 11 and 12 extend obliquely symmetrically from the middle of the length direction of the first support arm 10 and in a direction in which the tip portions spread out from each other.

The second support arms 11 and 12 are connected by a reinforcing beam 13 in the middle of the length direction. The reinforcing beam 13 is parallel to the first support arm 10, and the first support arm 10, the second support arms 11, 12 and the reinforcing beam 13 are formed in a trapezoidal shape in a plan view, which is close to a so-called truss structure. It has a structure. Since the frame has a structure similar to that of a truss structure, it is possible to increase the mechanical strength while having a relatively simple structure. The first support arm 10, the second support arms 11, 12 and the reinforcing beam 13 are connected via an appropriate connecting member so as to be located in the same plane.

Motors 102-2a and 102-4a are supported at both ends of the first support arm 10, respectively. Propellers 101-2a and 101-4a are attached to the rotary output shafts of the motors 102-2a and 102-4a, respectively, and each propeller is individually rotationally driven by the motors. Motors 102-1a and 102-3a different from the above motors are supported at the tips of the second support arms 11 and 12. Propellers 101-1a and 101-3a are attached to the rotary output shafts of the motors 102-1a and 103-3a, respectively, and each propeller is individually rotationally driven by the motors.

The lower frame has almost the same structure as the upper frame. The lower frame includes one first support arm 20 that supports the propeller drive motor at both ends, and two second support arms 21 and 22 extending from the first support arm 20. The second support arms 21 and 22 extend diagonally symmetrically from the middle of the length direction of the first support arm 20 and in a direction in which the tip portions spread out from each other. The first support arm 20 and the second support arms 21 and 22 are connected via appropriate coupling members so as to be located in the same plane.

The upper and lower frames are joined under the interposition of an appropriate number of columns so as to be parallel to each other. The pair of upper and lower second support arms 11 and 21 and the other pair of second support arms 12 and 22 are connected by columns 30 and 30 at intermediate portions in the length direction, respectively, via appropriate coupling members. Further, the pair of upper and lower first support arms 10 and 20 have columns 31 in the vicinity of the joints with the upper second support arms 11 and 21 and in the vicinity of the joints with the lower second support arms 12 and 22, respectively. , 31 are connected via an appropriate connecting member.

The pair of columns 30, 30 are connected by a reinforcing beam 23 at a position downward in the vertical direction. The reinforcing beam 23 is also a reinforcing beam of the lower frame composed of the first support arm 20 and the second support arms 21 and 22, and also functions as a reinforcing beam of the entire upper and lower frames. The reinforcing beam 13 is parallel to the first support arm 10, and the first support arm 10, the second support arms 11, 12 and the reinforcing beam 13 are formed in a trapezoidal shape in a plan view, which is close to a so-called truss structure. It has a structure.

The first support arm, the second support arm, the reinforcing beam, and the column connecting the upper and lower frames constituting the upper and lower frames are pipe-shaped members. Further, the above-mentioned members constituting the frame, at least the material of the first support arm, the second support arm and the reinforcing beam are made of a heat conductive material, for example, an aluminum alloy or a carbon fiber composite material. Examples of the carbon fiber composite material include carbon fiber reinforced plastic (CFRP) and carbon fiber reinforced carbon composite material. Since the material of the member constituting the frame is made of an aluminum alloy, a carbon fiber composite material, or the like and is a pipe-shaped member, the weight of the frame can be reduced while giving the frame the necessary strength. Further, as will be described in detail later, the heat dissipation effect can be enhanced.

[Propeller guard]
The propellers 101-1a and 101-1b supported by the tips of the pair of upper and lower second support arms 11 and 21 are surrounded by the propeller guard 41 and rotate in the propeller guard 41. The propeller guard 41 includes a pair of upper and lower annular frames, a columnar intervening member that connects these frames in parallel at regular intervals, a hub at the center of the upper and lower frames, and upper and lower frames. It has a plurality of spokes that connect to the hub. The upper and lower hubs are connected to the tips of the second support arms 11 and 21 so that their centers coincide with the rotation centers of the propellers 101-1a and 101-1b.

The propellers 101-2a and 101-2b supported by the right end of the pair of upper and lower first support arms 10 and 20 when viewed from the front are surrounded by the propeller guard 42 and rotate in the propeller guard 42.

The propellers 101-3a and 101-3b supported by the tips of the pair of upper and lower second support arms 12 and 22 are surrounded by the propeller guard 43 and rotate in the propeller guard 43.

The propellers 101-4a and 101-4b supported by the left end of the pair of upper and lower first support arms 10 and 20 when viewed from the front are surrounded by the propeller guard 44 and rotate in the propeller guard 44.

Each of the propeller guards 42, 43, 44 is configured in the same manner as the propeller guard 41. That is, each of the propeller guards 42, 43, 44 has a pair of upper and lower annular frames, a plurality of columnar intervening members that connect these frames in parallel, a hub at the center of the upper and lower frames, and upper and lower frames, respectively. It consists of a plurality of spokes that connect the frame and the hub. The upper and lower hubs of the propeller guard 42 are connected to the ends on the right side when viewed from the front of the first support arms 10 and 20. The upper and lower hubs of the propeller guard 43 are connected to the tips of the second support arms 12 and 22. The upper and lower hubs of the propeller guard 44 are connected to the left end of the first support arms 10 and 20 when viewed from the front.

The distance between the propellers 101-1a and 101-1b located on the right rear side of the drone and the propellers 101-2a and 101-2b located on the right front side is narrow, and the annular frame constituting these propeller guards 41 and 42 is formed. Are in contact. The distance between the propellers 101-3a and 101-3b located on the left rear side of the drone and the propellers 101-4a and 101-4b located on the left front side is also narrow, and the annular frame constituting these propeller guards 43 and 44 is formed. Are in contact.

It is desirable that the frames, hubs and spokes constituting each propeller guard 41, 42, 43, 44 are made of a heat conductive material. At least the spokes arranged in a grid pattern on the upper and lower surfaces of the propeller guards 41, 42, 43, 44 are preferably made of a heat conductive material.

The distance between the propellers located on the left and right is wider than the distance between the propellers located before and after the drone. That is, the distance between the propellers 101-4a and 101-4b located on the left and right sides of the drone and the propellers 101-2a and 101-2b and the distance between the propellers 101-3a and 101-3b and the propellers 101-1a and 101-1b are It's getting wider. These propeller guards 44 and 42 and 43, 41 are separated from each other.

[Built-in component support]
In a plan view, the lines connecting the rotation centers of the four sets of propellers 101-1a, 101-1b, 101-2a, 101-2b, 101-3a, 101-3b, 101-4a, and 101-4b are horizontally long. It is a rectangle. There is a space between the propeller guards 43 and 44 on the left side that are lined up in the front and rear and the propeller guards 41 and 42 on the right side that are lined up in the front and back. The built-in component support 50 is arranged.

The built-in component support 50 includes a flat dish-shaped bottom plate 51 and a cover 52 overlaid on the bottom plate 51. The bottom plate 51 and the cover 52 are made of a heat conductor such as an aluminum alloy or a carbon fiber composite material. The internal space surrounded by the bottom plate 51 and the cover 52 is a space for incorporating internal parts such as a power supply battery, a motor drive circuit, and a control circuit. The built-in component support 50 is long in the front-rear direction, and the planar shape at the front end in the traveling direction is semicircular.

The built-in component support 50 is arranged in the space formed between the left and right propellers and the left and right propeller guards 41, 42 and 43, 44, and between the upper and lower reinforcing beams 13, 23. The bottom plate 51 constituting the built-in component support 50 is connected to the lower reinforcing beam 23 via a connecting member. The connecting member is a plate-shaped member made of a material having good thermal conductivity, holds the reinforcing beam 23 over almost half a circumference, and is fastened with both side edges in surface contact with the bottom surface of the bottom plate 51.

The cover 52 constituting the built-in component support 50 is connected to the upper reinforcing beam 13 via the connecting member 59. The connecting member 59 is also a plate-shaped member made of a material having good thermal conductivity, and the reinforcing beam 13 is wound around about half a circumference and is fastened with both side edges in surface contact with the upper surface of the cover 52.

FIG. 9 shows an outline of component arrangement in the internal space of the built-in component support 50. Approximately half of the space 56 on the rear side (diagonally lower right side in FIG. 9) in the built-in component support 50 is close to the upper and lower reinforcing beams 13 and 23, and is a space having a high cooling effect. The space 56 is divided into upper and lower layers, and a battery mounting space 53 is provided in the upper layer portion. The battery mounting space 53 is provided with a battery receiving plate and appropriate fasteners so that two secondary batteries, that is, rechargeable batteries 55, can be arranged side by side in parallel.

FIG. 9 shows a state in which only one battery 55 is loaded. The battery 55 is also one of the heat generating parts, and is devised so as to suppress the temperature rise of the battery 55 by loading the battery 55 in the space 56 having a high cooling effect. The battery 55 itself is a component having high mechanical strength and rigidity, and the strength and rigidity of the built-in component support 50 can be increased by firmly tightening the battery 55 with a fastener and loading the battery 55. The battery 55, the battery mounting space 53, and the fasteners also contribute as members for ensuring the strength of the frame.

About half of the rear side of the cover 52 is a lid that can be opened and closed so that the battery 55 can be attached to and detached from the battery mounting space 53. The reinforcing beam 13 of the upper frame is provided so as to be displaced in front of the reinforcing beam 23 of the lower frame in order to enable opening and closing of the lid.

In the space 56, a mounting substrate for heat-generating components is arranged in the lower layer of the battery mounting space 53 in surface contact with the bottom plate 51. The rotation speed control component (ESC: Electronic Speed Control) of the motor and the step-down electric component are mounted on the mounting board. The step-down electric unit steps down the DC power supplied from the battery 55 to a voltage suitable for the drive voltage of the motor and the drive voltage of the control circuit and distributes the DC power supply. The above ESC and step-down electric machine generate high heat.

An appropriate number of circuit boards 58 are arranged on the bottom plate 51 of the built-in component support 50 in front of the space 56. A control circuit such as a flight controller, a signal processing circuit from various sensors, a communication circuit, and the like are mounted on these circuit boards 58.

A 6-axis sensor, which is a means for measuring the acceleration of the drone and calculating the speed by integrating the acceleration, is arranged on the back surface, that is, the lower surface side of the battery receiving plate constituting the battery mounting space 53. The 6-axis sensor has an acceleration sensor that detects accelerations in three axial directions that are orthogonal to each other, and an angular velocity sensor that detects angular velocities of rotation, for example, pitching, rolling, and yawing around the three axes. There is.

The position of the center of gravity of the drone when the two batteries 55 are loaded in the battery mounting space 53 is between the two batteries 55. On the other hand, the rotation center of the attitude control of the drone by the rotation control of the four sets of motors, that is, the horizontal line of the lift generated by the rotation of the four sets of motors is above the position of the center of gravity. In other words, the battery 55, which is a fixed weight object, is arranged below the horizon where lift is generated.

By setting the positional relationship between the position of the center of gravity and the horizontal line where lift is generated as described above, it is possible to stabilize the attitude of the drone and save energy required for attitude control.

Below the built-in component support 50, a chemical tank 104 is arranged with a space 70 between the built-in component support 50 and the lower surface of the built-in component support 50. Since the drug tank 104 contains the drug to be sprayed and the drug is sprayed while flying over the field, the drug tank 104 is a variable weight object. The drug tank 104, which is a variable weight object, is arranged further below the position of the center of gravity of the drone, and is considered so that the influence of the weight fluctuation on the attitude control of the drone is reduced.

[GPS sensor]
GPS sensors 60, 60 are attached upward to the two second support arms 11 and 12 constituting the upper frame. The GPS sensors 60, 60 are composed of, for example, an RTK antenna and an RTK-GPS (Real Time Kinematic-Global Positioning System) module. The GPS sensors 60, 60 measure the absolute position of the drone, determine whether the measured position is, for example, the position according to the program, and if the position is deviated, the rotation of each drive motor so as to be the correct position. To control.

When the GPS sensors 60, 60 vibrate, the absolute position measurement accuracy of the drone is lowered, and the position control system is also lowered. Therefore, in the illustrated embodiment, in the length direction of the second support arms 11 and 12, which are located at the maximum distance from each drive motor so as not to be affected by the vibration of each drive motor which is a vibration source. GPS sensors 60, 60 are installed in the middle part.

The GPS sensors 60 and 60 are installed between the front and rear propeller guards 41 and 42 and between the propeller guards 43 and 44 when viewed from the plane. Further, the second support arms 11 and 12 are located in the vicinity of the pillars 30 and 30 connecting the upper and lower frames of the GPS sensors 60 and 60 so as not to vibrate easily. Therefore, the GPS sensors 60 and 60 are not easily affected by the vibration of each of the drive motors, and the position of the drone can be measured with high accuracy.

[Frame cooling effect]
According to the configuration of the flying object and its frame described above, the following cooling effects can be obtained.

The built-in component support 50 is mounted with built-in components including a rotation control component of a motor and a heat generating component such as a distribution electric machine. The bottom plate 51 and the cover 52 constituting the built-in component support 50 are made of a heat conductive material, and the heat generated from the heat generating component is transmitted to the built-in component support 50 and dissipated. Therefore, the built-in component support 50 is a main part for dissipating the heat generated by the heat generating component.

Further, the bottom plate 51 of the built-in component support 50 is coupled to the reinforcing beam 23 of the lower frame made of the heat conductive material, and the reinforcing beam 23 is further coupled to the second support arms 21 and 22. The cover 52 of the built-in component support 50 is also connected to the reinforcing beam 13 of the upper frame made of the heat conductive material, and the reinforcing beam 13 is connected to the second support arms 11 and 12. In this way, the structure is such that the heat generated by the built-in component is easily transferred from the built-in component support 50 to the frame, and even if the heat dissipation by the built-in component support 50 is insufficient, the frame compensates for the heat dissipation. It has a structure.

The built-in component support 50 is surrounded by a pair of front and rear propellers located on the left and right sides thereof. When each propeller is rotationally driven, a downward flow of air is generated along the left and right side surfaces of the built-in component support 50. The downward flow of air flows at a relatively high speed in a substantially triangular space viewed from the plane direction defined by the left and right side surfaces of the built-in component support 50 and the front and rear propeller guards.

In this embodiment, the four propellers have a two-stage upper and lower configuration, and it is known that the downward flow is more concentrated and stronger than the one-stage propeller. As shown in FIG. 9a), under the two-stage propeller, the airflow is particularly high from the position at a distance of about 50% of the radius to the position of about 90% from the center of the propeller when viewed from above. There is a fast cylindrical region.

9b) is a schematic diagram of FIG. 9a), and reference numeral 401 is a schematic representation of the propeller in the above embodiment. As a typical design value, when the propeller diameter is 70 cm, the rotation speed is 2,000 rpm, and the airframe weight is 20 kg, the wind speed in this cylindrical region 402 is 10 m or more per second. .. It has been clarified by the inventor's experiment that by placing the drug nozzle in this cylindrical area and spraying the drug, this cylindrical area becomes a so-called protective wall and the undesired scattering of the drug to the outside can be minimized. It has become.

Note that FIG. 9c) is a reference diagram in which the same experimental results using a drone with a one-stage propeller are added. In the one-stage propeller configuration, the cylindrical region where the airflow velocity is high is not clear as in the case of the two-stage propeller configuration, and the concentration of the downward flow and the strength of the downward flow are inferior. Further, in the experiment by the inventor, it has been clarified that in the case of the one-stage propeller configuration, the unfavorable scattering of the drug to the outside of the field is rather increased due to the influence of the swirling flow of the propeller.

Therefore, in order to maximize the effect of the present invention, it is desirable to use a drone having a two-stage propeller configuration. Furthermore, by using the two-stage propeller configuration, the turbulence of the air flow can be reduced and the wind speed can be maintained, so that a secondary effect that the chemical can be effectively sprayed to the root of the crop in the field can be obtained. In order to positively utilize the airflow created by the drone propeller according to the above embodiment, the airflow reaching the crop is at a low altitude of about 7 meters per second, typically about 75 cm from the top of the crop in the field. It is good to fly.

As described above, in the present embodiment, both side surfaces of the built-in component support 50 and a part of the frame are located in the flow path of the downward flow generated intensively and at high speed by the two-stage propeller. There is. More specifically, a downward flow flows along both side surfaces of the built-in component support 50, and both ends of the first support arms 10 and 20, almost the entire second support arms 11, 12, 21 and 22, and the reinforcing beam. Both ends of 13 and 23 cross the flow path of the downward flow. Therefore, the heat transferred from the built-in component support 50 itself and the built-in component support 50 to the frame is effectively dissipated, and the temperature rise of the built-in component is suppressed.

While the drone is flying at a given speed, the windbreak of the drone cools the entire drone. However, the drone operating modes include a low-speed flight mode and a hovering mode, and in these operating modes, the cooling effect due to windbreak cannot be expected. However, according to the embodiment of the present invention, as described above, a device for promoting cooling is provided, and the temperature rise can be suppressed even in the low speed flight mode and the hovering mode.

Further, as can be seen from FIGS. 4 and 8, gaps 70 are formed at regular intervals between the lower surface of the bottom plate 51 of the built-in component support 50 and the upper surface of the drug tank 104. The gap 70 serves as an air flow path, and is devised so that the chemical tank 104 does not interfere with the cooling of the built-in component support 50. Combined with such ingenuity, it is possible to effectively prevent the temperature rise of the drone.

[Other Examples]
Fins for promoting cooling may be provided in the portion of the frame located in the flow path of the downward flow driven by the rotation of the propeller.

Although the cooling effect is enhanced according to the embodiment of the present invention, a certain temperature rise is unavoidable in the low speed flight mode and the hovering mode. When the temperature rises above the specified temperature in the low speed flight mode or hovering mode, an emergency cooling request is issued. Increase flight speed if there is an emergency cooling request. In order to increase the flight speed, it is necessary to increase the rotation speed of the propeller, and by increasing the rotation speed, the downward flow can be increased and the cooling effect can be enhanced. By increasing the flight speed, it is possible to obtain a cooling effect due to the windbreak of the built-in component support 50.

When the emergency cooling request is made, the yaw rotation motion may be performed to increase the downward flow. The yaw rotation motion is a motion to change the direction of the drone, and since this motion can increase the amount of air in contact with the built-in component support 50, it is possible to suppress the temperature rise even in the low speed flight mode and the hovering mode. can.

In order to accurately perform various controls such as drone speed control, direction control, and attitude control, it is necessary to quickly accelerate and decelerate individual propeller drive motors. In order to quickly decelerate the propeller drive motor, a discharge resistor that consumes the regenerative power from the propeller drive motor is used. The discharge resistor consumes regenerative power by generating heat and rapidly decelerates the propeller drive motor. In order to efficiently dissipate the heat generated by the discharge resistor, the discharge resistor may be arranged in contact with the built-in component support 50 made of the heat conductor.

As described above, as an example of this description, an agricultural chemical spraying drone has been described as an example, but the technical idea of the present invention is not limited to this, and can be applied to all drones.

10 1st support arm 11 2nd support arm 12 2nd support arm 13 Reinforcing beam 20 1st support arm 21 2nd support arm 22 2nd support arm 23 Reinforcing beam 30 Pillar 31 Pillar 41-44 Propeller guard 50 Built-in component support 51 Bottom plate 52 Cover 53 Battery mounting space 53 Attached member 60 GPS sensor

Claims (14)

An air vehicle having multiple propeller drive motors that rotate and drive multiple propellers individually.
A frame formed by combining a plurality of support arms that support the plurality of propeller drive motors, and
A built-in part support that is coupled to the frame supporting the internal components including the heat-generating component consists thermal conductor, was closed,
A part of the frame coupled to the heat conductor is located in the passage of the downward flow generated by the rotational drive of the propeller.
An air vehicle that increases the flight speed of the squadron when an emergency cooling request is made. An air vehicle having multiple propeller drive motors that rotate and drive multiple propellers individually.
A frame formed by combining a plurality of support arms that support the plurality of propeller drive motors, and
A built-in part support that is coupled to the frame supporting the internal components including the heat-generating component consists thermal conductor, was closed,
A part of the frame coupled to the heat conductor is located in the passage of the downward flow generated by the rotational drive of the propeller.
An air vehicle that increases the downward flow by performing a yaw rotation motion when an emergency cooling request is made.
The flying object according to claim 1 or 2, wherein the frame is made of a heat conductive material. The flying object according to claim 3, wherein the heat conductive material is an aluminum alloy or a carbon fiber composite material. The flying object according to any one of claims 1 to 4 , wherein the heat conductor is made of an aluminum alloy or a carbon fiber composite material. The flying object according to any one of claims 1 to 5 , wherein the heat generating component is a rotation control component of each propeller drive motor. The flying object according to any one of claims 1 to 6 , wherein the heat generating component is a distribution electric power that distributes electric power from a power source to a circuit component including each propeller drive motor. The propellers are arranged at a total of four locations in front, back, left and right in a plan view, the front and rear propellers are close to each other, the left and right propellers are separated from each other, and a thermal conductor supporting the internal component between the left and right propellers. The air vehicle according to any one of claims 1 to 7, wherein the aircraft is arranged. The flying object according to claim 8, wherein the space formed between the front and rear propellers and the heat conductor is a passage for a downward flow generated by the rotational drive of the propellers. 8. The described flying object. The flying object according to any one of claims 1 to 10, wherein each propeller is surrounded by a propeller guard, and the propeller guard is made of a heat conductive material. The flying object according to claim 10, wherein the propeller guard has lattices on the upper and lower surfaces, and the lattices are made of a heat conductive material. The flying object according to any one of claims 1 to 12, which has a discharge resistor that consumes regenerative power from the propeller drive motor, and the discharge resistor is in contact with the heat conductor. The flying object according to claim 7, wherein fins are provided in a portion of the frame in the passage of the descending flow.

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