Aircraft

Abstract

To provide an aircraft capable of inhibiting increase of the weight of the aircraft even if a tank filled with a fluid is mounted thereon.SOLUTION: An unmanned aircraft 1 flies by driving propellers 2 and includes at least an airframe 10 of the aircraft, motors 3 each serving as a drive part which drives the propeller 2, the propellers 2 attached to the airframe 10 through the motors 3, and a control device 4 which is housed in the airframe 10 and controls driving of the motors 3. At least part of the airframe 10 includes high pressure tanks 70 in which a fluid (hydrogen gas) is stored. The airframe 10 includes: a body 11 in which the control device 4 is housed; and multiple arms 12 which extend from the body 11 in a horizontal direction and to each of which the propeller 2 is attached through the motor 3. Each arm 12 includes the high pressure tank 70.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an aircraft that flies by driving a propeller. [Background technology]

[0002] As one example of this type of technology, an unmanned aerial vehicle is known that is equipped with a fuel cell system and multiple fuel tanks filled with fuel gas on its body (see, for example, Patent Document 1). The fuel cell system is supplied with fuel gas from the fuel tanks and is capable of generating electricity. The electricity generated by the fuel cell system is supplied to a motor attached to the body, which rotates a propeller connected to the motor, enabling the unmanned aerial vehicle to fly. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2019-145381 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, as in Patent Document 1, a tank filled with a fluid, such as a fuel tank, is mounted on the aircraft body, and the weight of the aircraft increases by the weight of the tank. As a result, it is expected that the aircraft's cruising range will be shortened, and the aircraft's load capacity, such as payload, will be reduced.

[0005] The present invention has been made in consideration of the above, and has an object to provide an aircraft that can suppress an increase in the weight of the aircraft even when tanks filled with fluid are installed. [Means for solving the problem]

[0006] In view of the above problems, the inventors conducted extensive research and determined that by including a tank in the aircraft fuselage, the tank could be given the function of ensuring the strength of the aircraft and the function of filling it with fluid, thereby reducing the number of parts in the aircraft and making the aircraft lighter.

[0007] The present invention is based on this idea, and the aircraft of the present invention is an aircraft that flies by driving a propeller, and comprises at least a body of the aircraft, a drive unit that drives the propeller, the propeller attached to the body via the drive unit, and a control device that is housed in the body and controls the drive of the drive unit, and is characterized in that at least a part of the body includes a tank that contains a fluid.

[0008] According to the present invention, by using a tank for containing a fluid in at least a part of the aircraft fuselage (i.e., the framework of the aircraft), the fluid can be stored in a part of the aircraft. This allows a single member to serve as both the member constituting the aircraft and the tank, thereby reducing the number of parts in the aircraft. As a result, the aircraft's cruising distance can be improved and the aircraft's payload can be increased.

[0009] In a more preferred embodiment, the airframe includes a main body that houses the control device, and a plurality of arms that extend horizontally from the main body and to which the propellers are attached via the drive units, the arms including the tank. According to this embodiment, by combining the arms and the tank into a single member, the number of parts can be efficiently reduced, and the weight of the aircraft can be reduced.

[0010] In a further preferred embodiment, the main body includes the tank. According to this embodiment, by using a single member that serves both as the main body and the tank, the number of parts can be efficiently reduced, making the aircraft lighter.

[0011] In particular, by using a tank having a liner that forms a storage space for storing fluid and a reinforcing layer made of fiber reinforced resin wrapped with fiber bundles to cover the outer peripheral surface of the liner, it is possible to obtain a lightweight arm and main body with high strength.

[0012] In a further preferred embodiment, the tank is a tank filled with hydrogen gas as the fluid, the aircraft has a fuel cell system that generates electricity using the hydrogen gas filled in the tank as fuel gas, the drive unit is a motor, and the drive unit and the control device are supplied with electricity generated by the fuel cell system.

[0013] According to this aspect, by using hydrogen gas as the fuel gas to be filled into the tank, the weight of the aircraft can be reduced compared to when liquefied fuel is used. Furthermore, the hydrogen gas can be used to generate electricity on board the aircraft, and the electricity can be used to drive the motor. As a result, the aircraft's cruising range can be extended compared to when liquefied fuel is used.

[0014] Furthermore, in a preferred embodiment, the tank is a tank filled with hydrogen gas as the fluid, and the drive unit is an engine that uses the hydrogen gas filled in the tank as fuel.

[0015] According to this aspect, by using hydrogen gas as the fuel gas to be filled into the tank, the weight of the aircraft can be reduced compared to the case of using liquefied fuel. Furthermore, since the hydrogen gas can be used as fuel and burned in the engine to drive the propeller, the aircraft's cruising distance can be extended even with this aspect. Effect of the Invention

[0016] According to the present invention, even if tanks filled with fluid are installed, the increase in weight of the aircraft can be suppressed. [Brief description of the drawings]

[0017] [Figure 1] FIG. 1 is a perspective view showing a schematic view of an unmanned aerial vehicle according to a first embodiment. [Diagram 2] 2 is a schematic diagram of a fuel cell system that drives the unmanned aerial vehicle shown in FIG. 1. [Diagram 3] 2 is an oblique view of a tank unit that forms a wall part of the main body that constitutes the fuselage of the unmanned aerial vehicle shown in FIG. 1. [Figure 4] 4 is a cross-sectional view taken along line AA of the tank unit shown in FIG. 3. [Diagram 5] 5 is an enlarged cross-sectional view of a main portion showing a portion where the high-pressure tank shown in FIG. 4 is attached to the aircraft body. [Figure 6] 2 is an enlarged cross-sectional view of a main portion showing a mounting portion of the high-pressure tank shown in FIG. 1 to an arm, the cross-sectional view being taken along line BB in FIG. [Figure 7] FIG. 11 is a perspective view showing a schematic view of an unmanned aerial vehicle according to a second embodiment. [Figure 8] FIG. 8 is a schematic system diagram including a hydrogen engine (internal combustion engine) that drives the unmanned aerial vehicle shown in FIG. 7. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] Hereinafter, embodiments of the present invention will be described with reference to the drawings. Components with the same reference numerals in each embodiment have the same functions in each embodiment unless otherwise specified, and description thereof will be omitted.

[0019] [First embodiment] First, an aircraft of a first embodiment, in particular a small unmanned aircraft that does not carry a crew member on board, will be described with reference to Fig. 1. Fig. 1 is a perspective view that shows a schematic view of the unmanned aircraft of the first embodiment. In Fig. 1, the unmanned aircraft 1 is an aircraft equipped with a fuel cell stack of a fuel cell system 5 as a power source. Note that, although the unmanned aircraft 1 is shown as an example in this embodiment, the configuration shown below may also be applied to a manned aircraft.

[0020] The unmanned aerial vehicle 1 shown in Fig. 1 can fly in various flight modes such as ascending, descending, turning, moving forward, backward, or hovering by rotating a propeller 2 with a motor 3 as a drive unit using power generated by a fuel cell stack. The unmanned aerial vehicle 1 can fly autonomously or by remote control. The unmanned aerial vehicle 1 may be configured as a multicopter type drone.

[0021] The unmanned aerial vehicle 1 at least comprises a body 10 of the unmanned aerial vehicle 1, a motor 3 as a drive unit that drives a propeller 2, the propeller 2 attached to the body 10 via the motor 3, and a control device 4 housed in the body 10 and that controls the drive of the motor 3. In this embodiment, six sets of motors 3 that drive the propellers 2 are provided.

[0022] In addition to the control device 4, the airframe 10 contains a fuel cell system 5 as a power generation device for flying the aircraft 1, and a secondary battery 6 that stores the power generated by the fuel cell system 5 and drives the motor 3. Note that Fig. 1 does not show cables connecting the control device 4 and the fuel cell system 5, cables connecting the fuel cell system 5 and the secondary battery 6, cables connecting the motor 3 and the fuel cell system 5 or the secondary battery 6, etc. The secondary battery 6 is not necessarily required, and the unmanned aircraft 1 may be flown by directly supplying the power generated by the fuel cell system 5 to the motor 3.

[0023] In addition to the control device 4 that controls the operation of the unmanned aerial vehicle 1, the airframe 10 further includes a communication device (not shown) that performs wireless communication with the outside of the unmanned aerial vehicle 1, and a sensor (not shown) that recognizes the surrounding environment of the unmanned aerial vehicle 1. The airframe 10 is configured by attaching each component of the fuel cell system 5, the control device 4, the communication device, and the sensor to the inside or outer surface of the main body 11 of the airframe 10.

[0024] For example, the fuel cell stack FC, secondary battery 6, air supply path 21, air compressor 22, etc., described below, of the fuel cell system 5 are attached inside the main body 11. A radiator 62, described below, of the fuel cell system 5 is attached, for example, facing the outside of the main body 11. Tanks (high-pressure tanks) filled with hydrogen gas, described below, of the fuel cell system 5 are attached as tank units T1 to T5 in a state where a plurality of these are arranged side by side (connected like a panel), as described in detail below.

[0025] The airframe 10 includes a main body 11 that houses the control device 4 and the like, and a plurality of arms 12 that extend horizontally from the main body 11 and have propellers 2 attached via motors 3 serving as drive units. In this embodiment, the airframe 10 has six arms 12 corresponding to six sets of propellers 2 and motors 3.

[0026] The main body 11 constituting the machine body 10 is formed of a hexahedron such as a rectangular parallelepiped, and in the illustrated example, one side is open and five sides are closed by walls. The five walls include high-pressure tanks 70 that contain a fluid, and the high-pressure tanks 70 constituting one wall of the machine body 10 are arranged in parallel to form a tank unit. Therefore, the machine body 10 includes tank units T1 to T5 that form the walls of the five sides of the machine body 10.

[0027] Specifically, the body 10 includes a tank unit T1 that corresponds to the bottom wall of the body 10, and tank units T2 to T4 that stand upright from the tank unit T1 and correspond to the side walls of the body 10. The body 10 also includes a tank unit T5 that corresponds to the top wall of the body 10 and is fixed to the upper ends of the tank units T2 to T4. Note that, although the multiple tank units T1 to T5 will be described later, in the explanation from FIG. 2 onwards, each of the tank units T1 to T5 will be described as a tank unit T.

[0028] In this embodiment, of the main body 11 constituting the machine body 10, a metal hexagonal columnar connection member (connector) 13 is fixed to the center of the tank unit T5 constituting the upper wall of the machine body 10. Arms 12 are fixed to the connection member 13 so as to extend in the horizontal direction. Specifically, the multiple arms 12 extend radially from the connection member 13. The connection member 13 is firmly fixed to the tank unit T5 on the upper surface, and the six arms 12 are firmly fixed to the connection member 13. In this embodiment, the connection member 13 functions as a manifold that supplies hydrogen gas to the fuel cell system 5, as described later.

[0029] For example, a reinforcing member (not shown) may be attached along the high-pressure tank 70 in the center of the tank unit T5, and the connecting member 13 may be firmly fixed to this reinforcing member. Alternatively, a reinforcing member (not shown) may be attached to span a pair of connecting members 90, 90 described below, and the connecting member 13 may be firmly fixed to this reinforcing member. Note that "firmly fixed" in this specification means that the fixing method is not particularly limited, and may include fixing with fastening members such as bolts and nuts, or fixing by welding, as long as the members can be stably fixed to each other except at the time of disassembly, etc.

[0030] Thus, the airframe 10 is formed of a hexahedral main body 11 made up of five tank units T1 to T5 combined together, a connection member 13 fixed to the center of the tank unit T5 located on the top surface of the main body 11, and six arms 12 fixed horizontally and radially at equal intervals from the connection member 13. Furthermore, in the unmanned aerial vehicle 1, a motor 3 is fixed to each tip of the six arms 12 as a drive unit relative to the airframe 10, and a propeller 2 is rotatably connected to the rotation shaft of the motor 3.

[0031] Here, the six arms 12 constituting the airframe 10 are configured to include tanks that contain fluids, and specifically, each arm 12 is formed of a hollow high-pressure tank. This high-pressure tank may be the same high-pressure tank as each of the high-pressure tanks 70 of the tank units T1 to T5 constituting the airframe 10 described below, or may be a high-pressure tank that is longer than these. In this embodiment, each high-pressure tank 70 contains hydrogen gas as the fuel gas used in the fuel cell system 5 mounted on the unmanned aerial vehicle 1, but the high-pressure tanks 70 may contain other fluids.

[0032] Next, the fuel cell system 5 that supplies power to the motor 3 and the control device 4 as a drive unit will be described with reference to Fig. 2. Fig. 2 is a schematic system diagram of the fuel cell system 5 that is mounted on the unmanned aerial vehicle 1 shown in Fig. 1 and drives the unmanned aerial vehicle 1.

[0033] As shown in Fig. 2, the fuel cell system 5 includes a fuel cell stack FC configured by stacking a plurality of fuel cells, each including a membrane electrode assembly (MEA) and the like. The fuel cell stack FC is connected to a secondary battery 6, and power generated by the fuel cell system 5 is stored in the secondary battery 6. The control device 4 shown in Fig. 1 is connected to the fuel cell system 5. In this embodiment, the control device 4 may be directly supplied with power generated by the fuel cell system 5, or may be supplied with power from the secondary battery 6. Note that the power generated by the fuel cell stack FC may be directly supplied to a load, such as the motor 3 that drives the propeller 2, without being stored in the secondary battery 6.

[0034] Furthermore, the fuel cell system 5 includes an air supply system 20 that supplies air to the fuel cell stack FC, a hydrogen gas supply system 40 that supplies hydrogen gas, which is a fuel gas, to the fuel cell stack FC, and a cooling system 60 that cools the fuel cell stack FC.

[0035] The air supply system 20 is a system that supplies air as an oxidant gas to the fuel cell stack FC, and also exhausts off-gas, including air, that has not been used in the electrochemical reaction in the fuel cell stack FC, from the fuel cell stack FC.

[0036] The air supply system 20 includes an air supply path 21 that supplies air to the fuel cell stack FC, and an air exhaust path 24 that exhausts off-gas containing air exhausted from the fuel cell stack FC to the atmosphere. The air supply path 21 includes an air cleaner 23 that removes dust and other particles contained in the air introduced from the atmosphere, and an air compressor 22 that pressurizes and sends the air that has passed through the air cleaner 23 to the fuel cell stack FC. The air compressor 22 is driven by a motor 22a that is driven by power generated by the fuel cell stack FC, and compresses the sucked air.

[0037] The air supply system 20 may include an air bypass path 25 that branches off from the air supply path 21 and merges with the air discharge path 24. The air bypass path 25 diverts a portion of the air compressed by the air compressor 22 to the air discharge path 24. The air supply system 20 may further include a pressure sensor 28 and a temperature sensor 29 that measure the pressure and temperature of the air, respectively, and an air flow meter 30 that measures the flow rate of the air. The air supply system 20 may also include an intercooler (not shown) that cools the air compressed from the air compressor 22.

[0038] The hydrogen gas supply system 40 is a system that supplies hydrogen gas as a fuel gas to the fuel cell stack FC, and also discharges off-gas, which contains hydrogen gas that has not been used in the electrochemical reaction in the fuel cell stack FC, from the fuel cell stack FC.

[0039] The hydrogen gas supply system 40 includes a hydrogen gas supply path 42 that supplies hydrogen gas from the tank unit T (specifically, a high-pressure tank 70) to the fuel cell stack FC, and a hydrogen gas discharge path 48 that discharges off-gas discharged from the fuel cell stack FC to the air discharge path 24. The hydrogen gas supply system 40 includes a main stop valve 43 that switches between introducing and stopping the introduction of hydrogen gas filled in the high-pressure tank 70 into the hydrogen gas supply path 42, and a regulator 44 that adjusts the pressure of the hydrogen gas introduced from the high-pressure tank 70. The hydrogen gas supply system 40 includes an ejector 45 that ejects hydrogen gas, the pressure of which has been adjusted by the regulator 44, to the fuel cell stack FC, and relief valves 46, 47 that release excessive pressure that may occur in the hydrogen gas supply path 42.

[0040] The hydrogen gas supply system 40 is provided in a hydrogen gas discharge path 48, and includes a gas-liquid separator 49 that separates generated water from the off-gas discharged from the fuel cell stack FC. The hydrogen gas supply system 40 includes a hydrogen gas circulation path 50 that circulates hydrogen gas contained in the off-gas that has passed through the gas-liquid separator 49 to the ejector 45. The hydrogen gas circulation path 50 may be provided with a hydrogen gas pump that pressure-feeds the hydrogen gas that has passed through the gas-liquid separator 49 to the ejector 45. The hydrogen gas supply system 40 includes a drain valve 51 that switches between discharging the generated water that has passed through the gas-liquid separator 49 to the air discharge path 24 and stopping the discharge. The hydrogen gas supply system 40 may include a pressure sensor 52 that measures the pressure of the hydrogen gas.

[0041] The cooling system 60 is a system that circulates coolant to cool the fuel cell stack FC. The cooling system 60 includes a coolant circulation path 61 that circulates coolant between the fuel cell stack FC and a radiator 62, and a radiator 62 that cools the coolant discharged from the fuel cell stack FC. The cooling system 60 includes a water pump 63 that pumps the coolant cooled by the radiator 62 to the fuel cell stack FC. The water pump 63 is driven by a motor 63a that is driven by power generated by the fuel cell stack FC. The cooling system 60 includes a reservoir tank 64 that stores spare coolant and adjusts the pressure of the coolant, and a fan 65 that cools the radiator 62.

[0042] The cooling system 60 includes a compressor cooling path 66 that diverts the cooling water flowing through the cooling water circulation path 61 to the air compressor 22 to cool the air compressor 22. The compressor cooling path 66 supplies a portion of the cooling water pumped from the water pump 63 to the air compressor 22, and discharges the cooling water discharged from the air compressor 22 to the radiator 62. The cooling system 60 may include a temperature sensor 67 that measures the temperature of the cooling water, and may also include an ion exchanger that removes ions from the cooling water.

[0043] Next, the tank unit T constituting the main body 11 of the body 10 of the unmanned aerial vehicle 1 will be described with reference to Figures 3 to 5. Note that Figures 3 to 5 are schematic diagrams of one tank unit T among the tank units T1 to T5 shown in Figure 1, and the number of tanks constituting the tank unit T is one example, and differs from the number of tanks in the tank units T1 to T5 shown in Figure 1. As shown in Figure 3, the tank unit T according to this embodiment is panel-shaped and includes multiple high-pressure tanks 70 and a pair of connecting members 90, 90 that are connected to both ends of the multiple high-pressure tanks 70 and fix the multiple high-pressure tanks 70 in a parallel state.

[0044] The high-pressure tank 70 is a tank mounted on the unmanned aerial vehicle 1, and is a tank filled with high-pressure hydrogen gas. The gas that can be filled into the high-pressure tank 70 is not limited to high-pressure hydrogen gas, and may be various compressed gases such as CNG (compressed natural gas), various liquefied gases such as LNG (liquefied natural gas) and LPG (liquefied petroleum gas), and other gases (fluids) as long as it is not used in the fuel cell system 5, and may be temporarily filled with a fluid such as a liquid for a pressure test.

[0045] 4, the high-pressure tank 70 includes a liner 71 in which a storage space S for storing hydrogen gas is formed and in which openings 73 are formed on both sides, and a reinforcing layer 72 laminated on the liner 71 so as to cover an outer peripheral surface 71a of the liner 71. The liner 71 is made of a material having gas barrier properties, and the reinforcing layer 72 is made of a fiber-reinforced resin.

[0046] The high-pressure tank 70 includes a body portion 74 including the above-mentioned storage space S, and a pair of neck portions 75, 75 that are continuous with the end of the body portion 74 and have an opening 73 formed therein. In this embodiment, the neck portions 75, 75 are formed on both sides of the high-pressure tank 70, but the high-pressure tank 70 may have a bottle-like structure in which the neck portion 75 is formed only on one side. Both the body portion 74 and the neck portion 75 have a structure in which a liner 71 and a reinforcing layer 72 are laminated together.

[0047] In this embodiment, the body portion 74 includes a cylindrical main body portion 74a, which is an example of a cylindrical shape, and a shoulder portion 74b whose inner and outer diameters decrease from the main body portion 74a toward the end of the body portion 74. The shoulder portion 74b is a cylindrical portion having a truncated cone shape, and a neck portion 75 is formed so as to be continuous with the shoulder portion 74b. In a cross-sectional shape, the neck portion 75 is formed of parallel wall surfaces obtained by laminating the liner 71 and the reinforcing layer 72.

[0048] As shown in Fig. 5, an annular base 80 is attached to the outer peripheral surface 72a of the reinforcing layer 72 of the neck portion 75. A plurality of protrusions are formed on the inner peripheral surface 82 of the base 80, and the reinforcing layer 72 is formed so as to bite into the inner peripheral surface 82. This allows the base 80 to be engaged with the reinforcing layer 72. A male thread is formed on the outer peripheral surface 81 (see Fig. 5) of the base 80, and this male thread can be screwed into a female thread on an inner wall surface 94 formed on a connecting member 90 described later.

[0049] In this embodiment, it is preferable that the resin constituting the liner 71 is a resin having good gas barrier properties. Examples of such a resin include thermoplastic resins such as polypropylene resin, nylon resin (e.g., 6-nylon resin or 6,6-nylon resin), polycarbonate resin, acrylic resin, ABS resin, polyamide resin, polyethylene resin, ethylene-vinyl alcohol copolymer resin (EVOH), and polyester resin.

[0050] The reinforcing layer 72 is formed by impregnating reinforcing fibers with a thermoplastic resin or a thermosetting resin as a matrix resin. In this embodiment, the reinforcing fibers are fiber bundles. As the reinforcing fibers, glass fibers, aramid fibers, boron fibers, carbon fibers, and other reinforcing fibers can be used, and in particular, carbon fibers are preferably used from the viewpoints of light weight, mechanical strength, and the like. As the matrix resin, a thermosetting resin is preferable, and as the thermosetting resin, a phenol-based resin, a melamine-based resin, a urea-based resin, or an epoxy-based resin is preferable, and from the viewpoints of mechanical strength, and the like, an epoxy resin precursor is preferably used. The epoxy-based resin has fluidity in an uncured state, and becomes an epoxy-based resin that forms a tough cross-linked structure after thermal curing.

[0051] The reinforcing layer 72 is formed by winding, by a filament winding method or a sheet winding method, a fiber bundle impregnated with a matrix resin around the outer peripheral surface 71a of the liner 71. The reinforcing layer 72 may be a helically wound layer in which the fiber bundle is wound so as to be inclined with respect to the axis line CL of the high-pressure tank 70, or may be, for example, a layer in which the fiber bundle is woven so as to be inclined with respect to the axis line CL of the high-pressure tank 70.

[0052] The pair of connecting members 90, 90 are connected to the neck portion 75 of the high-pressure tank 70, and are made of a metal such as aluminum or steel. The pair of connecting members 90, 90 are composed of a bracket 90A and a manifold 90B. The bracket 90A integrally holds one end of the multiple high-pressure tanks 70, 70, and the manifold 90B integrally holds the other end of the multiple high-pressure tanks 70, 70, forming a tank unit T. The airframe 10 of the unmanned aerial vehicle 1 of this embodiment is formed into a main body 11 by combining five tank units T, which will be described in detail later.

[0053] The manifold 90B is a member in which a gas flow path is formed, which introduces hydrogen gas into the storage space S of the high-pressure tank 70 and releases the hydrogen gas from this storage space S. As shown in Fig. 3, the bracket 90A and the manifold 90B differ mainly in whether or not a gas flow path is formed, so the structure of the manifold 90B as the connection member 90 will be described with reference to Fig. 5.

[0054] 5, the manifold 90B is formed so as to cover the opening 73 formed at the end of the high-pressure tank 70 in the direction of the axis CL, and the manifold 90B is formed with an insertion portion 91 and a cap portion 92. The cap portion 92 is a portion that is screwed onto the nozzle 80 and covers the end face of the high-pressure tank 70, and the insertion portion 91 is formed in the center of the cap portion 92.

[0055] The insertion part 91 is a plug-shaped part that is inserted from the opening 73 along the inner circumferential surface 71b of the liner 71 in the neck part 75 of the high-pressure tank 70. An annular groove 95 is formed in the outer circumferential surface 91a of the insertion part 91 along the circumferential direction, and annular seal members 96, 97 that seal the storage space S are disposed in the annular groove 95. The seal members 96, 97 are made of a resin material having gas barrier properties or an elastic material such as a rubber material.

[0056] The manifold 90B is formed with vents 98 that introduce and release hydrogen gas as a fluid into the storage space S along the axis CL of the high-pressure tank 70. The vents 98 also serve as flow paths for supplying the hydrogen gas stored in the storage space S to the fuel cell system 5. The vents 98 formed in the insertion portions 91 inserted into the openings 73 of the high-pressure tanks 70 are connected to each other by the manifold 90B and are gathered into a communication passage 99 so that the hydrogen gas can be supplied to the fuel cell stack FC via piping or the like (not shown).

[0057] The connecting member 13 is connected to the high-pressure tanks 70 corresponding to the six arms 12, and has a connection structure similar to that of the manifold 90B, as shown in Fig. 6. The connecting member 13 is formed so as to cover openings 73 formed at the ends of the high-pressure tanks 70 in the direction of the axis CL, and the connecting member 13 is screwed into the base 80 to fix each of the high-pressure tanks 70 so that each of the high-pressure tanks 70 extends radially in the horizontal direction from the connecting member 13. An insertion portion 91 is formed in the portion where each high-pressure tank is fixed.

[0058] The insertion part 91 is a plug-shaped part that is inserted from the opening 73 along the inner peripheral surface 71b of the liner 71 in the neck part 75 of the high-pressure tank 70. An annular groove 95 is formed in the outer peripheral surface of the insertion part 91 along the circumferential direction, and annular sealing members 96, 97 that seal the storage space S are disposed in the annular groove 95. The sealing members 96, 97 are made of a resin material having gas barrier properties or an elastic material such as a rubber material.

[0059] The connecting member 13 is formed with a vent hole 98 that introduces hydrogen gas as a fluid into the storage space S and releases it along the axis CL of the high-pressure tank 70. This vent hole 98 also serves as a flow path for supplying the hydrogen gas stored in the storage space S to the fuel cell system 5. The vent holes 98 formed in the insertion parts 91 inserted into the openings 73 of the high-pressure tanks 70 are connected to each other by the connecting member 13 and are collected into a communication passage 99, which is configured to be supplied to the fuel cell stack FC through piping or the like (not shown). The end on the tip side of the high-pressure tank 70 (arm 12) connected to the connecting member 13 is sealed by a housing of the motor 3 having a structure similar to that of the bracket 90A shown in FIG. 4.

[0060] The manifolds 90B and the communication passages 99 of the connection member 13 are connected to the fuel cell stack FC via pipes (not shown). The arm 12 is provided with wiring (not shown) for supplying the electric power generated by the fuel cell system 5 to the motor 3. This wiring may pass through the accommodation space S in the arm 12 or may be arranged along the outer periphery of the arm 12.

[0061] As described above, the airframe 10 of the unmanned aerial vehicle 1 of this embodiment has five panel-like tank units T as wall sections, so the main body 11 of the airframe 10 can be neatly assembled using the tank units T. Furthermore, the tank units T1 to T5 shown in Fig. 1 can be easily connected to each other at their respective brackets 90A and manifolds 90B via fixing brackets (not shown) or the like.

[0062] Furthermore, a hexagonal prism-shaped connecting member 13 is fixed to the tank unit T5 of the main body 11, and a plurality of arms 12, which are high-pressure tanks 70, are screwed to the connecting member 13 so as to extend horizontally and radially from the connecting member 13. This allows the arm 12 (high-pressure tank 70) to be easily removed from the connecting member 13 and a new arm 12 (high-pressure tank 70) to be attached to the connecting member 13 when replacing the arm 12 as a used high-pressure tank 70.

[0063] As described above, the unmanned aerial vehicle 1 uses a high-pressure tank 70 that contains a fluid in at least a portion of the body 10 of the unmanned aerial vehicle 1, allowing the fluid to be stored in a portion of the body 10. This allows the number of parts in the unmanned aerial vehicle 1 to be reduced by using a single component that serves both as the components constituting the body 10 and the high-pressure tank 70. As a result, the flying distance of the unmanned aerial vehicle 1 can be improved, and the payload of the unmanned aerial vehicle 1 can be increased.

[0064] Specifically, the airframe 10 includes a main body 11 formed by connecting a plurality of panel-shaped tank units T each having a plurality of high-pressure tanks 70 arranged therein. The airframe 10 further includes arms 12 extending horizontally radially from a connecting member 13, and the arms 12 are also made of high-pressure tanks 70. In this way, by combining the members constituting the main body 11 and the high-pressure tanks 70 into a single member, and by combining the plurality of arms 12 and the high-pressure tanks 70 into a single member, the number of parts can be efficiently reduced, and the weight of the unmanned airframe 1 can be made lighter.

[0065] In particular, by using a high-pressure tank 70 having a liner 71 forming a storage space S and a reinforcing layer 72 made of fiber-reinforced resin covering the outer peripheral surface of the liner 71, a main body 11 and arm 12 that are lightweight and have high strength can be obtained.

[0066] When the fuel cell system 5 is started up by a communication device mounted on the body 10 of the unmanned aerial vehicle 1, air is supplied as oxidant gas to the fuel cell stack FC by an air supply system 20. The off-gas containing air discharged from the fuel cell stack FC is discharged into the atmosphere through an air discharge path 24.

[0067] Meanwhile, hydrogen gas is supplied to the fuel cell stack FC by a hydrogen gas supply system 40, and the fuel cell stack FC generates electricity through an electrochemical reaction. At this time, hydrogen gas filled in a plurality of high-pressure tanks 70 of a tank unit T constituting a part of the main body 11 of the vehicle body 10 and a plurality of high-pressure tanks 70 constituting a plurality of arms 12 is supplied to the fuel cell stack FC. Generated water is separated from the off-gas containing hydrogen gas discharged from the fuel cell stack FC by a gas-liquid separator 49, and the off-gas containing hydrogen gas separated by the gas-liquid separator 49 is discharged into the atmosphere through the air discharge path 24. The off-gas containing hydrogen gas separated by the gas-liquid separator 49 is circulated to a hydrogen gas circulation path 50 via an ejector 45.

[0068] The power generated by the fuel cell stack FC is supplied to the control device 4, and then supplied from inside the main body 11 of the airframe 10 through a wiring (not shown) and a connecting member 13, and from the arm 12 to the motor 3. As a result, under the control of the control device 4, the propeller 2 can be rotated to fly the unmanned aerial vehicle 1. In this way, since the fuel cell system 5 uses hydrogen gas in the high-pressure tank 70 that constitutes the airframe 10, the weight of the unmanned aerial vehicle 1 can be reduced and the flying distance of the unmanned aerial vehicle 1 can be extended. Furthermore, since the unmanned aerial vehicle 1 generates power using the fuel cell system 5, it is not necessary to mount a heavy secondary battery for flight.

[0069] Second Embodiment The unmanned aerial vehicle 1 according to the second embodiment will be described below with reference to FIGS. 7 and 8. The main difference between the unmanned aerial vehicle 1 according to this embodiment and that of the first embodiment is that a hydrogen engine (internal combustion engine) 3A is used instead of a motor as a drive unit that is the power source of the unmanned aerial vehicle 1. Therefore, since the propeller 2 is driven by the engine 3A, the structure of the airframe 10 including these connected devices is also different. Below, the differences from the first embodiment will be mainly described, and in FIGS. 7 and 8, the devices and configurations common to the first embodiment are given the same reference numerals and detailed description will be omitted. Note that the power transmission mechanism 36 shown in FIG. 8 is omitted in FIG. 7.

[0070] As shown in Fig. 7, in this embodiment, the aircraft 1 has an airframe 10 having a structure similar to that of a helicopter, and the airframe 10 has a main body 11 and a tail section 17. The main body 11 has substantially the same structure as that of the first embodiment, and the tail section 17 is integrally formed with the main body 11. As in the first embodiment, the control device 4, the battery 6A, etc. are mounted inside the main body 11.

[0071] Furthermore, an engine 3A (a so-called hydrogen engine) that is driven by burning hydrogen gas is attached to the upper part of the main body 11. The engine 3A is attached to the propeller 2 via a power transmission mechanism 36 (see FIG. 8), a power shaft 31, etc. Furthermore, a tail rotor 33 is provided in the tail section 17, and the tail rotor 33 is attached to the engine 3A via a power transmission mechanism 36 such as a drive shaft (not shown).

[0072] The engine 3A may be a normal single-cylinder or multi-cylinder engine as shown below, or may be a turboshaft engine used in normal aircraft. A power transmission mechanism 36 that transmits power from the engine 3A to the propeller 2 has a structure similar to that of a known power transmission mechanism of a helicopter, and therefore a detailed description thereof will be omitted. For example, when the engine 3A is a cylinder engine, the engine 3A includes a cylinder block, a piston, a gas injection valve that injects hydrogen gas, and an addition plug that adds hydrogen gas. The power mechanism includes a transmission (not shown) and a clutch (not shown). A detailed description thereof will be omitted.

[0073] As shown in FIG. 8, the control device 4 is started and stopped by power from a battery 6A, and in addition to controlling each device of the hydrogen gas supply system 40 shown in the first embodiment, it also controls the combustion of the engine 3A and the power mechanism of the transmission (not shown).

[0074] The engine 3A is connected to a hydrogen gas supply system 40. The control device 4 is connected to electronic devices such as a gas injection valve (not shown) of the engine 3A and an ignition plug. In this embodiment, the engine 3A can be driven by injecting hydrogen gas from the hydrogen gas supply system 40 into a combustion chamber (not shown) of the engine 3A and igniting (burning) the hydrogen gas with an ignition plug (not shown). As a result, the power of the engine 3A is transmitted to the propeller 2 via a power mechanism, enabling the aircraft 1 to fly. Furthermore, the control device 4 controls the rotation and stopping of the propeller 2 and the tail rotor 33 and the rotation speed thereof by controlling a transmission (not shown) and a clutch (not shown). As a result, the flight of the aircraft 1 can be controlled.

[0075] Although the embodiments of the present invention have been described in detail above, the present invention is not limited to the above embodiments, and various modifications can be made without departing from the spirit of the present invention described in the claims. In the present invention, the configuration of one embodiment can be added to the configuration of another embodiment, the configuration of one embodiment can be replaced with the configuration of another embodiment, or a part of the configuration of one embodiment can be deleted.

[0076] For example, an example has been shown in which five faces of a hexahedron are made up of tank units as the main body constituting the airframe of the unmanned aerial vehicle, but all six faces may be made up of tank units, or the tank unit on one face may be opened and closed so that the equipment housed inside can be maintained and inspected. In addition, the shape is not limited to a hexahedron, and it is of course possible for the tank unit to have a solid shape of another shape, such as a cylinder. In addition, in the second embodiment, an aircraft with a structure similar to that of a helicopter has been shown, but for example, an aircraft structure similar to that of a propeller plane may be adopted. [Explanation of symbols]

[0077] 1: unmanned aerial vehicle (aircraft), 2: propeller, 3: motor (driving unit), 3A: engine (driving unit), 4: control device, 5: fuel cell system, 10: airframe, 11: main body, 12: arm, 13: connecting member, 70: high-pressure tank (tank), T, T1 to T5: tank unit

Claims

1. An aircraft that flies by driving a propeller, an aircraft fuselage; A drive unit that drives the propeller; The propeller attached to the airframe via the drive unit; A control device that is housed in the aircraft body and controls the drive of the drive unit, At least a portion of the vehicle body includes a tank for containing a fluid; The airframe includes a main body in which the control device is housed, a plurality of arms extending horizontally from the main body and to which the propellers are attached via the drive unit; the wall portion of the main body is configured as a panel-shaped tank unit to which the tanks are fixed by a pair of connecting members connected to both ends of each tank in a state in which the tanks are arranged in parallel, the pair of connecting members includes a bracket that integrally holds one end of the plurality of tanks and a manifold that integrally holds the other end of the plurality of tanks, an air intake manifold for intake of a gas from the storage space of each of the tanks;

2. The aircraft described in claim 1, characterized in that the arm includes the tank.

3. the tank is a tank filled with hydrogen gas as the fluid, the aircraft has a fuel cell system that generates electricity using the hydrogen gas filled in the tank as fuel gas, the drive unit is a motor, 3. The aircraft according to claim 1, wherein the drive unit and the control device are supplied with electric power generated by the fuel cell system.

4. the tank is a tank filled with hydrogen gas as the fluid, 2. The aircraft according to claim 1, wherein the drive unit is an engine fueled by hydrogen gas filled in the tank.

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