Power generation equipment

Abstract

To provide a lighter power generation device that can be mounted on aerial drones. [Solution] The power generation device 1 generates electricity to be supplied to the motor 103b of the drone 100, and comprises a tank 60 for storing fuel, an engine 5 that is driven by the fuel supplied from the tank 60, a generator 10 that generates electricity when the rotation of the rotating shaft of the engine 5 is transmitted, and a cooling unit that cools the generator 10 by flowing a cooling medium through the generator 10, the cooling medium being the liquid fuel stored in the tank 60.

Description

Technical Field

[0001] The present invention is applicable to unmanned aerial vehicles generically called drones, and relates to a power generation device that generates electricity for a propulsion motor of a drone.

Background Art

[0002] In recent years, unmanned aerial vehicles generically called drones and operating remotely or autonomously have been used in many fields such as aerial photography and material transportation. Also, in recent years, it has been desired to increase the flight distance and flight time of drones in order to extend the shooting time or increase the transportation volume.

[0003] Therefore, conventionally, the technology described in Patent Document 1 has been proposed. According to Patent Document 1, a turbine is rotated by high-temperature gas generated by combustion of a mixture of fuel supplied to a combustor and compressed air supplied from a compressor, and a rotating electrical machine is rotationally driven by the rotation of the turbine, thereby generating electricity. A gas turbine generator for power generation is mounted on a drone body, and a drone that rotates a plurality of rotor blades by the electric power generated by this generator is disclosed. Further, according to Patent Document 1, it is disclosed that by enabling the loading of a necessary amount of fuel, an increase in the weight of the drone is suppressed.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In a system where a generator's motor is driven by a drive unit such as an engine that rotates a turbine using fuel, the generator generates heat, leading to a decrease in power generation efficiency. Therefore, it is necessary to cool the generator. Generally, it is known that cooling water is used to cool the generator.

[0006] However, in the case of a generator mounted on a drone to supply electricity to the motors that rotate the drone's rotor blades, if cooling water is also loaded onto the drone to cool the generator, the total weight of the drone increases, which reduces the drone's flight range and flight time.

[0007] This invention has been made in view of these problems, and aims to provide a power generation device that generates electricity to supply to the propulsion motor of a flying drone, while also enabling cooling and reducing its weight. [Means for solving the problem]

[0008] To achieve the above objective, the present invention has the following configuration.

[0009] (1) A power generation device (e.g., power generation device 1) that generates electricity to supply to a propulsion motor (e.g., motor 103b) of a flying drone (e.g., drone 100), A tank section for storing fuel (for example, tank 60), A drive unit (for example, an engine 50) that is driven by fuel supplied to the tank section, A power generation unit (for example, power generation unit 12) that generates electricity by receiving the rotation of the rotating shaft of the drive unit, The system includes a cooling section (for example, a tank 60, a groove 14d) that cools the power generation section by flowing a cooling medium through it, The power generation device is characterized in that the cooling medium is a liquid fuel contained in the tank.

[0010] According to invention (1), the fuel contained in the tank is used as a cooling medium for the power generation unit. Therefore, there is no need to prepare a separate cooling medium for the power generation unit. Therefore, it becomes possible to cool and reduce the weight of the power generation device that generates electricity to supply power to the propulsion motors of the flying drone. Furthermore, this configuration allows for longer flight distances and flight times for the drone.

[0011] (2) In (1), The aforementioned power generation unit is A spindle (for example, spindle 12a) that rotates due to the rotation of the aforementioned rotating shaft, A rotor (for example, rotor 12b) that rotates due to the rotation of the spindle, A stator (for example, stator 12c) facing the rotor, The system comprises a casing (for example, an inner casing 14) that houses the rotor and the stator, A channel (for example, a groove 14d) is formed on the outer surface of the casing through which the cooling medium supplied by the cooling unit flows. The power generation device is characterized in that the flow path reciprocates in a direction along the spindle.

[0012] In the power generation section, the spindle rotates, so the temperature due to heat generation is approximately the same in the direction of spindle rotation. On the other hand, in the direction along the spindle, the temperature due to heat generation differs between the tip and base ends of the spindle, depending on the winding direction of the rotor coils, etc. Therefore, if the flow path extends along the direction of spindle rotation and gradually moves towards the tip and base ends, the cooling efficiency decreases after the cooling medium has passed through a relatively high-temperature area.

[0013] According to invention (2), since the flow path reciprocates in a direction along the spindle, the cooling medium is frequently delivered to the front and rear sides of the power generation section in the direction along the spindle. This allows the power generation section to be cooled efficiently.

[0014] (3) In (2), a protruding portion (for example, protruding portion 14e) is formed in the flow path, A power generation device characterized in that the cooling medium meanders in the flow path by the protruding portion.

[0015] According to the invention of (3), since a protruding portion is formed in the flow path, the contact area with the cooling medium around the power generation portion can be increased. Thereby, the power generation portion can be cooled more efficiently.

Effect of the Invention

[0016] According to the present invention, it is possible to cool a power generation device that generates electricity supplied to a propulsion motor of a flying drone and suppress the weight.

Brief Description of the Drawings

[0017] [Figure 1] It is a perspective view showing the appearance of a drone 100 equipped with a power generation device 1 in an embodiment of the present invention. [Figure 2] It is a block diagram showing the configuration of the electrical system and drive system of the power generation device 1 in an embodiment of the present invention. [Figure 3] It is a side view showing a unit connecting a generator 10 and an engine 50. [Figure 4] It is a perspective view showing the appearance of the generator 10. [Figure 5] It is an exploded perspective view showing the components of the generator 10. [Figure 6] It is a perspective view showing the appearance of the inner casing 14. [Figure 7] It is an explanatory view showing the flow path of the cooling medium.

Mode for Carrying Out the Invention

[0018] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0019] [Configuration of Drone 100] Figure 1 is a perspective view showing the appearance of a drone 100 equipped with a power generation device 1 according to one embodiment of the present invention. Figure 2 is a block diagram showing the configuration of the electrical system and drive system of the power generation device 1 according to one embodiment of the present invention.

[0020] As shown in Figure 1, the drone 100 includes a power generator 1, a frame body 101 on which the power generator 1 is mounted, a plurality of horizontal arm sections 102 extending horizontally from the frame body 101, rotor blades 103 attached to the tips of the horizontal arm sections 102, and a lower arm section 104 attached to the bottom of the frame body 101 to contact the ground during landing. In addition, as shown in Figure 2, the frame body 101 is also equipped with a receiver 105 that receives operation information transmitted from a control controller 200 operated by the pilot, a detection device that detects the attitude and speed of the aircraft, a flight controller 106 that controls the attitude and speed of the aircraft based on the detection results of these detection devices, a power supply unit 107 that supplies electricity to the receiver 105, the flight controller 106, and the rotor blades 103, etc.

[0021] The power generation device 1 comprises a generator 10, an engine 50 that rotates the generator 10, and a tank 60 that contains fuel supplied to the engine 50. The engine 50 is, for example, a jet engine. The generator 10 and the engine 50 are connected in series to the tank 60 by piping 70. The liquid fuel contained in the tank 60 is used as a cooling medium to cool the generator 10, and after the generator 10 has been cooled, a portion of it is used to drive the engine 50. The fuel that is not used to drive the engine 50 is returned to the tank 60. In this way, the fuel contained in the tank 60 circulates in the order of generator 10 and then engine 50.

[0022] The rotor blade 103 includes a propeller 103a and a motor 103b that rotates the propeller 103a. The motor 103b is attached to the tip of a horizontal arm 102 and rotates using electricity from a power supply 107. According to this embodiment, twelve horizontal arm 102s extend from the frame body 101, and when the frame body 101 is viewed from above, twelve rotor blades 103 are arranged at the vertices of a regular dodecagon.

[0023] Figure 3 is a side view showing a unit connecting the generator 10 and the engine 50. The generator 10 generates electricity by rotating a spindle 12a (see Figure 4), as will be described in detail later. The electricity generated by the generator 10 is stored in the battery of the power supply unit 107. The engine 50 has a combustor that generates high-temperature gas by burning a mixture of fuel supplied from the tank 60 and compressed air supplied from the compressor, and a turbine that rotates using the high-temperature gas refined in the combustor. A rotating shaft 52 extends from the central axis of this turbine. The generator 10 and the engine 50 are positioned facing each other so that the central axis of the spindle 12a (see Figure 4) of the generator 10 and the central axis of the rotating shaft 52 of the engine 50 coincide, and the two are connected by a connecting member 55, and the spindle 12a (see Figure 4) and the rotating shaft 52 are also connected. As a result, the rotation of the turbine in the engine 50 causes the rotating shaft 52 to rotate, and this rotation is transmitted to the spindle 12a (see Figure 4), causing the spindle 12a to rotate. This causes the generator 10 to generate electricity.

[0024] Then, when the pilot operates the control controller 200, electricity is supplied from the power supply unit 107 to the motor 103b, causing the propeller 103a to rotate and the drone 100 to fly. While the drone 100 is flying, the flight controller 106 controls the rotation of the 12 rotor blades 103 based on the operation information transmitted from the control controller 200 and the speed and attitude information of the drone 100, so that the drone 100 moves through the air in response to the pilot's controller operations.

[0025] Figure 4 is a perspective view showing the external appearance of the generator 10, and Figure 5 is an exploded perspective view showing the components of the generator 10. The generator 10 comprises a power generation unit 12, an inner casing 14, an outer casing 15, a front cover 16, a rear cover 17, packings 18 and 19, a cooling medium supply joint 20, and a cooling medium discharge joint 21. In Figures 4 and 5, for the convenience of the following explanation, the side facing the engine 50 will be referred to as the front, and the opposite side as the rear. Also, in Figure 4, the outer casing 15 is depicted as transparent to show its interior.

[0026] In Figure 5, the power generation unit 12 comprises a spindle 12a, a rotor 12b, and a stator 12c. The spindle 12a extends in the front-rear direction, with its front end rotatably supported by the front cover 16 and its rear end rotatably supported by the rear cover 17. It is connected to the rotating shaft 52 in the engine 50 and is the rotating shaft to which the rotation of the rotating shaft 52 is transmitted.

[0027] The rotor 12b is a cylindrical member with permanent magnets arranged on its outer circumference and is fixed to the spindle 12a. The stator 12c is a cylindrical member with coils arranged on it and is fixed inside the inner casing 14. The power generation unit 12 is constructed by arranging the rotor 12b inside the stator 12c, and the central axis of the spindle 12a, the central axis of the rotor 12b, and the stator 12c coincide.

[0028] The inner casing 14 is a flange-shaped member having a cylindrical portion 14a capable of housing the stator 12c, and a ring-shaped flange portion 14b extending radially from one edge of the cylindrical portion 14a.

[0029] Figure 6 is a perspective view showing the external appearance of the inner casing 14. The flange portion 14b has a stepped portion 14c at the edge of the opening formed on the inside. This stepped portion 14c is formed by the front surface of the flange portion 14b and a ring-shaped bottom surface formed at a lower position relative to this front surface. The diameter of the opening formed in the center of this ring-shaped bottom surface coincides with the inner diameter of the cylindrical portion 14a.

[0030] A groove 14d is formed on the side surface of the cylindrical portion 14a in the inner casing 14. The groove 14d extends linearly along the central axis direction of the cylindrical portion 14a. In this embodiment, 24 grooves 14d are formed and are arranged at equal intervals in the circumferential direction. Here, one specific groove 14d in the groove 14d is referred to as the first specific groove 140, and the groove 14d located on the opposite side of the first specific groove 140 is referred to as the second specific groove 141. The first specific groove 140 and the grooves 14d, 14d on both sides are connected at their front ends. These two adjacent grooves 14d, 14d and the grooves 14d, 14d further next to them are connected at their rear ends. The grooves 14d, 14d further next to them are connected at their front ends. In this way, the grooves 14d are formed to meander from the first specific groove 140 toward both sides in the circumferential direction. Furthermore, the second specific groove 141 and the grooves 14d, 14d adjacent to it are connected at their rear ends.

[0031] Projections 14e are formed on the bottom surface of grooves 14d other than the first specific groove 140 and the second specific groove 141. The projections 14e have a rhombic columnar shape at the bottom surface, with multiple short diagonals of the rhombus arranged at equal intervals along the longitudinal direction of the groove 14d. In addition, triangular prism-shaped projections 14f extend from the wall surface of grooves 14d other than the first specific groove 140 and the second specific groove 141 toward the space between adjacent projections 14e, 14e. The upper surfaces of projections 14e and projections 14f are included in the cylindrical surface which includes the outer circumferential surface of the cylindrical portion 14a.

[0032] In Figure 5, the outer casing 15 has a cylindrical portion 15a whose outer diameter is approximately equal to the outer diameter of the flange portion 14b of the inner casing 14 and which can accommodate the cylindrical portion 14a inside, a front joint mounting portion 15b that protrudes radially in a rectangular prism shape from the front end on the side surface of the cylindrical portion 15a, and a rear joint mounting portion 15c that protrudes radially in a rectangular prism shape from the rear end on the side surface of the cylindrical portion 15a. The central part of the outer circumference of the cylindrical portion 15a is formed in a concave shape. The front joint mounting portion 15b and the rear joint mounting portion 15c are positioned point-symmetrically with respect to the center of the outer casing 15.

[0033] The front joint mounting portion 15b has a cylindrical through hole 15d that extends from the top surface toward the inner surface of the cylindrical portion 15a. The rear joint mounting portion 15c has a cylindrical through hole 15e that extends from the top surface toward the inner surface of the cylindrical portion 15a.

[0034] The front cover 16 is a cover that closes the front opening of the outer casing 15. The front cover 16 has a hole formed therein for inserting the front end of the spindle 12a. The rear cover 17 is a cover that closes the rear opening of the outer casing 15. The packing 18 is a ring-shaped member positioned at the stepped portion 14c and sealing the space between the stator 12c and the inner casing 14. The packing 18 is a ring-shaped member that seals the space between the rear cover 17 and the outer casing 15.

[0035] Then, the rotor 12b is inserted into the inner casing 14 to house the stator 12c, and the inner casing 14 is then housed inside the outer casing 15. At this time, the flange 14b of the inner casing 14 is brought into contact with the front end of the outer casing 15, and the outer casing 15 is positioned relative to the inner casing 14 such that the through hole 15d faces the first specific groove 140 and the through hole 15e faces the second specific groove 141. At this time, the central axis of the spindle 12a, the central axis of the inner casing 14, and the central axis of the outer casing 15 coincide.

[0036] Furthermore, a packing 18 is placed on the front side of the outer casing 15, and a packing 19 is placed on the rear side, and the front cover 16 and rear cover 17 are bolted to the outer casing 15. As a result, the front end of the spindle 12a protrudes from the center of the front cover 16, and the rear end of the spindle 12a protrudes from the center of the rear cover 17. Also, a hole is formed in the rear cover 17 through which the three-phase output terminals of the stator 12c pass, and the three-phase output terminals of the stator 12c protrude from the rear cover 17. Furthermore, various ring members are attached to the front cover 16 and rear cover 17 to stabilize the position of both ends of the spindle 12a. Then, by attaching the cooling medium supply fitting 20 to the front fitting mounting part 15b and the cooling medium discharge fitting 21 to the rear fitting mounting part 15c, the generator 10 shown in Figure 4 is assembled.

[0037] The cooling medium supply fitting 20 connects the front fitting mounting portion 15b to the piping 70 and is installed in the through hole 15d of the front fitting mounting portion 15b. The cooling medium discharge fitting 21 connects the rear fitting mounting portion 15c to the piping 70 and is installed in the through hole 15e of the rear fitting mounting portion 15c. The other end of the piping 70, one end of which is connected to the front fitting mounting portion 15b and the rear fitting mounting portion 15c, is connected to the tank 60. Alternatively, the other end of the piping 70, one end of which is connected to the rear fitting mounting portion 15c, may be connected to the fuel supply portion of the engine 50.

[0038] By housing the inner casing 14 inside the outer casing 15, the outer surface of the inner casing 14 and the inner surface of the outer casing 15 come into contact or close proximity. This creates a flow path between the inner casing 14 and the outer casing 15, from the through hole 15d of the front joint mounting portion 15b through the groove 14d to the through hole 15e of the rear joint mounting portion 15c. By supplying liquid fuel contained in the tank 60 as a cooling medium to this flow path, the power generation unit 12 inside the inner casing 14 can be cooled. In this way, the tank 60, the through hole 15d, the groove 14d, and the through hole 15e constitute a cooling unit for cooling the power generation unit 12.

[0039] Although not shown in the diagram, the cooling unit may include a pump that sends liquid fuel as a cooling medium from the tank 60 to the power generation unit 12, a control valve that controls whether to send fuel from the tank 60 to the engine 50 or to the power generation unit 12, and a controller that controls this control valve.

[0040] Furthermore, the generator 10 may also be equipped with an inverter that converts AC voltage to DC voltage in order to supply the electricity (AC voltage) generated by the power generation unit 12 to the motor 103b for propulsion of the drone 100, which is driven by DC voltage electricity. In this case, since the inverter also generates heat, a heat exchange unit may be provided in the inverter, and piping 70 may be connected to this heat exchange unit to supply liquid fuel and cool the inverter.

[0041] Figure 7 is an explanatory diagram showing the flow path of the cooling medium, where Figure 7(a) shows the side into which the cooling medium flows, and Figure 7(b) shows the side out which the cooling medium flows.

[0042] As shown in Figure 7(a), the cooling medium is supplied to the first specific groove 140 from the through hole 15d of the front joint mounting portion 15b (see Figure 5). The cooling medium supplied to the first specific groove 140 moves rearward along the central axis of the inner casing 14 and moves to the rear side of the adjacent grooves 14d, 14d. Furthermore, the cooling medium moves from the rear to the front side of the adjacent grooves 14d, 14d, meandering through the multiple protrusions 14e. Having moved from the rear to the front side of the adjacent grooves 14d, 14d, the cooling medium then moves from the front to the rear side of the next adjacent grooves 14d, 14d, meandering through the multiple protrusions 14e. In this way, the cooling medium reciprocates along the groove 14d in a direction along the central axis of the spindle 12a, and as shown in Figure 7(b), moves from the grooves 14d, 14d adjacent to the second specific groove 141 to the front end of the second specific groove 141. Then, the cooling medium moves to the rear end of the second specific groove 141 and is discharged to the outside of the generator 10 through the through hole 15e of the rear joint mounting portion 15c (see Figure 5).

[0043] As described above, according to this embodiment, fuel contained in the tank 60 is used as a cooling medium. The tank 60 and the front joint mounting portion 15b are connected by piping 70, and the engine 50, the rear joint mounting portion 15c, and piping 70 are connected. The fuel supplied from the tank 60 to the generator 10 as a cooling medium undergoes heat exchange through the wall surface of the groove portion 14d or the protrusion portion 14e, and the power generation unit 12 is cooled by cooling the groove portion 14d or the protrusion portion 14e.

[0044] Alternatively, fuel whose temperature has risen through heat exchange with the power generation unit 12 may be supplied to the engine 50. This improves the fuel vaporization efficiency.

[0045] When the drone 100 is in use, electricity is supplied from the power supply unit 107 to the stator 12c, which rotates the rotor 12b and thereby rotates the turbine of the engine 50. In other words, the power generation unit 12 is used as a starter motor. In this state, the engine 50 is driven, and once the turbine is rotating stably, the supply of electricity from the power supply unit 107 to the stator 12c is stopped, and the rotation of the rotor 12b is switched to the engine 50. This makes the drone 100 ready for flight.

[0046] As described above, this embodiment uses the fuel contained in the tank 60 as a cooling medium. Therefore, there is no need to separately prepare a cooling medium for the power generation device 1. This makes it possible to cool the power generation device 1 while also reducing its weight. With this configuration, it is possible to keep the total weight of the drone 100 low, and the flight distance and flight time of the drone 100 can be extended.

[0047] Furthermore, multiple grooves 14d, which serve as flow paths for the cooling medium, extend along the central axis of the spindle 12a. The cooling medium supplied from the front joint mounting portion 15b moves alternately from front to rear and rear to front, circulating around the side surface of the inner casing 14, and is discharged from the rear joint mounting portion 15c.

[0048] In the case where the flow path of the cooling medium is helical and extends in the direction of rotation of the spindle 12a, the cooling medium on the rear side of the power generation unit 12 is heated more than the front side, making it difficult to cool the rear side of the power generation unit 12. According to this embodiment, the cooling medium moves alternately from the front to the rear and from the rear to the front of the power generation unit 12, so that the cooling medium reaches both the front and rear sides of the power generation unit 12, allowing the power generation unit 12 to be cooled evenly. Furthermore, since the cooling medium can flow from the first specific groove 140 to the second specific groove 141 in both counterclockwise and clockwise directions, it is possible to shorten the path through which the cooling medium flows. This allows the power generation unit 12 to be cooled efficiently.

[0049] Furthermore, since the protrusion 14e is erected from the bottom surface of the groove 14d, the contact area between the cooling medium and the inner casing 14 around the power generation unit 12 can be increased. This allows the power generation unit 12 to be cooled more efficiently.

[0050] Although embodiments of the present invention have been described above, the embodiments of the present invention are not limited to those described above. For example, in the embodiments described above, the engine 50 is a jet engine, but it may be any other type of engine; in short, any engine that rotates a rotating shaft using an internal combustion engine is applicable. [Explanation of Symbols]

[0051] 1. Power generation equipment 10 Generators 11 spindles 12 Power Generation Section 12a Rotor 12b Stator 14. Inner casing 14a Cylindrical section 14b Tsubabe 14c Step section 14d Groove 14e Protrusion 14f Protrusion 15. Outer casing 15a Cylindrical section 15b Front joint mounting section 15c Rear joint mounting section 15d, 15e through hole 16 Front lid 17 Rear lid 18, 19 Packing 20 Cooling medium supply fitting 21 Cooling medium discharge fitting 50 engine 52 Rotation axis 55 Connecting member 60 tanks 70 Piping 100 Drones 101 Frame Body 102 Horizontal arm section 103 Rotary Wing 103a Propeller 103b Motor 104 Lower arm section 105 Receiver 106 Flight Controller 107 Power supply 140 First Specific Ditch Section 141 Second Specific Ditch Section 200 control controllers

Claims

1. A power generation device that generates electricity to supply power to the propulsion motor of a flying drone, A tank section for storing fuel, The drive unit is powered by the fuel supplied to the tank section, A power generation unit that generates electricity by transmitting the rotation of the rotating shaft of the drive unit, The system includes a cooling unit that cools the power generation unit by flowing a cooling medium through it, The power generation device is characterized in that the cooling medium is a liquid fuel contained in the tank.

2. The aforementioned power generation unit is A spindle that rotates due to the rotation of the aforementioned rotating shaft, A rotor that rotates due to the rotation of the spindle, A stator facing the rotor, The casing comprises the rotor and the stator, A channel is formed on the outer surface of the casing through which the cooling medium supplied by the cooling unit flows. The power generation apparatus according to claim 1, characterized in that the flow path reciprocates in a direction along the spindle.

3. A protrusion is formed in the aforementioned flow path. The power generation apparatus according to claim 2, characterized in that the cooling medium meanders within the flow path due to the protruding portion.

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