Wind propulsion device

Abstract

To improve aerodynamic characteristics. [Solution] The wind-powered propulsion device of the embodiment is a wind-powered propulsion device installed on a moving body that generates a propulsive force by receiving wind, and comprises a rotating body that is rotatable around a rotation axis and has a frame that is formed in an annular shape around a rotation axis, and a plurality of blades that are fixed to the frame and are provided such that imaginary straight lines connecting their respective ends in a direction perpendicular to the rotation axis are parallel, and the plurality of blades include a central blade whose imaginary straight line connecting its respective ends passes through the center of the frame.

Description

Technical Field

[0001] The present invention relates to a wind propulsion device.

Background Art

[0002] Patent Document 1 discloses a sailing ship provided with vertical wings that rotate around a vertical axis in a windmill shape, a propeller is connected to the vertical axis, and it can be propelled based on wind power. The trailing edge of the vertical wing is connected to a wire extending from an axis eccentric in the downwind direction with respect to the axis of rotation of the leading edge of the vertical wing. The vertical wing is configured to be swingable around the axis of rotation of the leading edge of the vertical wing. Patent Document 2 discloses a wind power generator including a main shaft extending in the vertical direction, an upper bearing provided at the upper part of the main shaft, a lower bearing provided at the lower part of the main shaft, a frame connected to the main shaft via the upper bearing and the lower bearing, blades attached to the main shaft, a motor shaft core connected to the main shaft via the lower bearing, and a generator connected to the motor shaft core.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] In a sailing ship provided with vertical wings that rotate around a vertical axis extending in the vertical direction as in Patent Document 2, for the purpose of propelling based on wind power as in Patent Document 1, in order to reduce the drag of the axis of rotation, a cylinder may be provided at the central part. If the cylinder is made too thick to increase strength and rigidity, the aerodynamic characteristics consisting of lift and rotational force will deteriorate. Note that the aerodynamic characteristics are the combined lift (force perpendicular to the wind, Magnus force) and rotational force (power generation energy, forward rotation speed, no-load rotation speed).

[0005] The present invention has been made to solve the above problems and aims to provide a wind-powered propulsion device that can improve aerodynamic characteristics. [Means for solving the problem]

[0006] As a means of solving the above problems, an embodiment of the present invention has the following configuration. (1) An embodiment of the present invention is a wind-powered propulsion device installed on a moving body that generates a propulsive force by receiving wind, comprising a rotating body having a frame formed in an annular shape around a rotation axis and rotatable around the rotation axis, and a plurality of blades each fixed to the frame and provided such that imaginary straight lines connecting their respective ends in a direction perpendicular to the rotation axis are parallel, wherein the plurality of blades include a central blade whose imaginary straight line connecting its respective ends passes through the center of the frame.

[0007] This configuration improves aerodynamic characteristics compared to having nothing in the center of the frame or having a cylinder in the center, by providing a central wing at the center of the frame.

[0008] (2) In the wind propulsion device described in (1) above, the central blade may have a closed cross section when viewed in cross-section that intersects the axial direction along the rotation axis.

[0009] (3) In the wind propulsion device described in (1) above, the frame is made of a rigid body, and the plurality of blades may be made of something other than a rigid body.

[0010] (4) In the wind propulsion device described in (1) or (2) above, the central wing may include a central column provided at the center of the frame when viewed from the axial direction along the rotation axis, and a resin wing body provided so as to cover the central column.

[0011] (5) In the wind propulsion device described in (1) or (2) above, the central wing may include, when viewed from the axial direction along the rotation axis, a central column provided at the center of the frame, a pair of support columns provided at both ends of the imaginary straight line, and a wing body composed of the pair of support columns and the central column and a cloth stretched over them.

[0012] (6) In the wind propulsion device described in (1) or (2) above, the central wing may include a pair of support columns provided at both ends of the imaginary straight line when viewed from the axial direction along the rotation axis, and a wing body made of cloth stretched between the pair of support columns.

[0013] (7) In the wind propulsion device described in any of (1) to (6) above, the blades other than the central blade among the plurality of blades may be curved radially outward with respect to the imaginary straight line.

[0014] (8) In the wind propulsion device described in any of (1) to (7) above, the rotating body may further have a propeller-shaped beam portion whose both ends are connected to the inner circumference of the frame portion and which connects the plurality of blades to each other.

[0015] (9) In the wind propulsion device described in any of (1) to (8) above, the plurality of blades may be arranged such that both ends are located on a virtual circle centered on the rotation axis.

[0016] (10) In the wind propulsion device described in any of (1) to (9) above, the plurality of blades may be arranged such that they are symmetric with respect to a center line that passes through the center of the frame and is parallel to the imaginary straight line when viewed from the axial direction along the rotation axis.

[0017] (11) In the wind propulsion device described in any of (1) to (10) above, the plurality of blades may be arranged such that, when viewed from the axial direction along the rotation axis, the blades pass through the center of the frame and are symmetric with respect to a center line perpendicular to the imaginary straight line.

[0018] (12) In the wind propulsion device according to any one of (1) to (11) above, when viewed from the axial direction along the rotation axis, among the plurality of blades, the ones on the center side of the frame portion may be provided such that the length of the virtual straight line is 1 / 2 or more of the diameter of the frame portion.

[0019] (13) In the wind propulsion device according to any one of (1) to (12) above, the plurality of blades may be in a shape twisted so that a first virtual straight line connecting both ends of each of the plurality of blades at a first position on the rotation axis and a second virtual straight line connecting both ends of each of the plurality of blades at a second position different from the first position on the rotation axis intersect when viewed from the axial direction along the rotation axis.

Advantages of the Invention

[0020] According to the present invention, the aerodynamic characteristics can be improved.

Brief Description of the Drawings

[0021] [Figure 1] It is a perspective view of the wind propulsion system of the first embodiment. [Figure 2] It is a diagram showing an example of the functional configuration of the wind propulsion system of the first embodiment. [Figure 3] It is a diagram showing an example of the flow of energy etc. in the wind propulsion system together with a comparative example. [Figure 4] It is a perspective view of the wind propulsion device of the first embodiment. [Figure 5] It is a perspective view of the first position of the plurality of blades in the wind propulsion device of the first embodiment as viewed from above. [Figure 6] It is a perspective view of the second position of the plurality of blades in the wind propulsion device of the first embodiment as viewed from above. [Figure 7] It is a comparison diagram of the effects (lift force, drag force, rotational force) of the number of blades. [Figure 8] It is a comparison diagram of the effects (lift force, drag force, rotational force) of the blade shape. [Figure 9] It is a comparison diagram of the effects (lift force, drag force, rotational force) of the central blade. [Figure 10] This is a perspective view of the wind propulsion device according to the second embodiment. [Figure 11] This is a schematic diagram showing the central wing of a wind power propulsion device according to the second embodiment. [Figure 12] This is a schematic diagram showing the central wing of a wind propulsion device according to the third embodiment. [Figure 13] This is a view of the wind propulsion device of the fourth embodiment, seen from the vertical direction. [Modes for carrying out the invention]

[0022] Hereinafter, embodiments of the wind propulsion device and wind propulsion system of the present invention will be described with reference to the drawings. In the following description, expressions indicating relative or absolute arrangements such as "parallel," "orthogonal," "center," and "coaxial" will not only mean such arrangements strictly, but will also include states in which the components are relatively displaced with tolerances or angles and distances that allow the same function to be obtained. In the drawings used in the following description, the scale of each component has been appropriately changed in order to make each component recognizable.

[0023] <Wind power propulsion system> Figure 1 is a perspective view of the wind power propulsion system 100 according to the first embodiment. Figure 2 is a diagram showing an example of the functional configuration of the wind power propulsion system 100 according to the first embodiment. Referring together to Figures 1 and 2, the wind power propulsion system 100 is installed on a ship 2 (an example of a mobile body) and comprises a wind power propulsion device 1 that generates thrust by receiving wind, and a wind turbine sail control device 140 (an example of a wind power control device) that controls the wind power propulsion device 1.

[0024] The wind power propulsion system 1 includes a wind turbine sail body 111 that is rotatable around a rotation axis RC (see Figure 4) that extends vertically from the hull 3. The wind power propulsion system 1 further includes an electric motor 41 that rotates the wind turbine sail body 111. The wind turbine sail body 111 includes an assembly 4 that includes a plurality of plate-shaped blades 10A to 10I that are integrally connected and rotatable around the rotation axis.

[0025] The wind propulsion device 1 has a frame portion 21 formed in an annular shape around a rotation axis RC, and comprises rotating bodies 20A and 20B that can rotate around the rotation axis RC, and a plurality of blades 10A to 10I that are fixed to the frame portion 21 and arranged so that the imaginary lines connecting their respective ends in a direction perpendicular to the rotation axis RC are parallel (see Figure 4). The plurality of blades 10A to 10I include a central blade 10A whose imaginary line connecting its respective ends passes through the center of the frame portion 21. The rotating bodies 20A and 20B having the frame portion 21 and the plurality of blades 10A to 10I constitute an assembly 4.

[0026] The wind power control device 140 includes a speedometer 65 that acquires the moving speed of the ship 2, a detection unit 7 that acquires wind condition information including the current wind speed and wind direction in the area where the ship 2 is located, a calculation unit 126 that calculates the relative wind direction applied to the wind power propulsion device 1 based on the acquired moving speed of the ship 2 and wind condition information, and a rotation control unit 40 that controls the electric motor 41 according to the calculated relative wind direction to adjust the rotation speed of the wind turbine sail body 111. The wind power propulsion device 1 that constitutes the wind power propulsion system 100 functions as a wind turbine sail that propels the ship 2 by receiving wind and generating lift.

[0027] The wind power propulsion system 100 includes a wind power propulsion device 1 comprising the wind turbine sail body 111, detection unit 7, receiving unit 8, and rotation control unit 40 described above; a remote control device 120 comprising an operating unit 121 operated to control the propulsion speed of the ship 2, and a determination unit 134 that determines the target thrust of the wind power propulsion device 1 and the target thrust of the propeller 51 driven by the prime mover 50 attached to the ship 2 according to the operating position of the operating unit 121; a wind turbine sail control device 140 that controls the rotation speed of the wind turbine sail body 111 around the rotation axis according to the target thrust of the wind power propulsion device 1; and a prime mover control device 150 that controls the rotation speed of the prime mover 50 according to the target thrust of the propeller 51. The wind power propulsion system 100 constitutes a system (ship integrated propulsion system) that integrates and controls two types of propulsion: propulsion by the wind power propulsion device 1 and propulsion by the propeller 51 driven by the prime mover 50.

[0028] The vessel 2 is equipped with a remote control device 120, a prime mover 50, a shaft 52, a propeller 51, a shaft horsepower meter 55, a detection system 60, a speedometer 65, and a prime mover control device 150. The vessel 2 does not necessarily have to be operated by a crew. For example, the vessel 2 may be an autonomously operated vessel.

[0029] The remote control device 120 executes a program (hereinafter referred to as the "ship control program") that controls the operation of the ship 2. The remote control device 120 functions as a device comprising a general control unit 130, an operation unit 121, a communication unit 122, an output unit 123, a calculation unit 126, and a storage unit 124 by executing the ship control program. The remote control device 120 includes a general control unit 130 that controls the operation of each functional unit of the remote control device 120.

[0030] The central control unit 130 includes a processor 131, such as a CPU (Central Processing Unit), connected by a bus, and a memory 132. The processor 131 reads the ship control program stored in the storage unit 124 and stores the read ship control program in the memory 132. The processor 131 executes the ship control program stored in the memory 132.

[0031] The control unit 130 communicates with the prime mover control unit 150, for example, by controlling the operation of the communication unit 122. The control unit 130 acquires information input via, for example, the operation unit 121. The control unit 130 records information generated by, for example, the execution of the ship control program in the storage unit 124. The control unit 130 acquires the rotational speed of the prime mover 50, for example. The control unit 130 outputs the acquired rotational speed to the prime mover control unit 150, for example. In the following description, the actual rotational speed value of the prime mover 50 acquired (determined) by the control unit 130 is also referred to as the "actual rotational speed".

[0032] The control unit 121 is a handle for controlling the speed and direction of the vessel 2. The control unit 121 accepts input from the crew. By operating the control unit 121, the crew inputs either the target engine speed or the engine direction of rotation, or both, to the remote control device 120. The target engine speed is the target rotational speed of the prime mover 50. The engine direction of rotation is the direction of rotation of the prime mover 50. The direction of rotation of the prime mover 50 is either forward or reverse. The direction of travel of the vessel 2 when the direction of rotation of the prime mover 50 is forward is opposite to the direction of travel of the vessel 2 when the direction of rotation of the prime mover 50 is reverse.

[0033] The control unit 121 outputs the target rotational speed indicated by the crew's operation to the control unit 130. The control unit 121 also outputs information indicating the engine rotation direction indicated by the crew's operation (hereinafter referred to as "rotation direction information") to the control unit 130. Note that the control unit 121 does not necessarily have to be operated by a crew member. For example, if the ship 2 is operating autonomously, the control unit 121 may be operated by the control unit 130 in accordance with the ship control program.

[0034] The communication unit 122 includes a communication interface for connecting the remote control device 120 to the shaft horsepower meter 55, the detection system 60, the speedometer 65, and the prime mover control device 150. The communication unit 122 communicates with the shaft horsepower meter 55, the detection system 60, the speedometer 65, and the prime mover control device 150, for example, via either wired or wireless communication. The communication unit 122 transmits information such as target rotational speed, actual rotational speed, and rotational direction to the prime mover control device 150.

[0035] The output unit 123 includes a display device such as a CRT (Cathode Ray Tube) display, a liquid crystal display, or an organic EL (Electro-Luminescence) display, as well as an output device such as a speaker or other audio output device. The output unit 123 may also be configured as an interface for connecting these output devices to the device. The output unit 123 outputs information related to the remote control device 120. For example, the output unit 123 outputs the operation results of the operation unit 121.

[0036] The calculation unit 126 is configured to include a processor such as a CPU (Central Processing Unit) connected by a bus (an example of a processing unit). The calculation unit 126 calculates various information related to the remote control device 120. For example, the calculation unit 126 calculates the relative wind direction on the wind propulsion device 1 based on the acquired moving speed of the ship 2 and wind condition information.

[0037] The memory unit 124 is configured using a storage device such as a magnetic hard disk drive or a semiconductor storage device. The memory unit 124 stores various information related to the remote control device 120. The memory unit 124 pre-stores, for example, a ship control program. The memory unit 124 stores, for example, information generated by the execution of the ship control program. The memory unit 124 stores, for example, a history of operations performed by the crew on the control unit 121. The memory unit 124 stores, for example, a history of the actual rotational speed of the prime mover 50.

[0038] The prime mover 50 is the engine that generates the propulsion force for the ship 2. The prime mover 50 converts the energy contained in the fuel into power. The type of fuel and the mechanism of operation of the prime mover 50 can be anything as long as it can convert the energy contained in the fuel into power. The prime mover 50 is, for example, a two-stroke diesel engine. The prime mover 50 may also be, for example, a four-stroke diesel engine or a gas engine. For the sake of simplicity, the ship 2 will be described below using the example of the prime mover 50 being a two-stroke engine.

[0039] The shaft 52 rotates due to the power generated by the prime mover 50. The rotational speed of the shaft 52 is proportional to the rotational speed of the prime mover 50. By rotating, the shaft 52 transmits the power generated by the prime mover 50 to the propeller 51.

[0040] The propeller 51 rotates due to the power generated by the prime mover 50. The rotation of the propeller 51 generates thrust that moves the ship 2.

[0041] The shaft horsepower meter 55 measures the power generated by the prime mover 50. The shaft horsepower meter 55 measures the power generated by the prime mover 50 by detecting the torsional strain occurring in the shaft 52 using either an electrical method, an optical method, or both.

[0042] The detection system 60 includes a sensor for detecting the rotational speed of the prime mover 50. The detection device may include, for example, a proximity sensor. The proximity sensor may be configured to output an ON signal when metal is located within a certain distance and an OFF signal when metal is not located within a certain distance. In this case, the proximity sensor outputs an ON signal when a convex portion of the irregularities on the surface of the shaft 52 is located within the detection range, and an OFF signal when a concave portion is located within the detection range. The detection system 60 may detect the rotational speed of the prime mover 50 based on such changes in the output of the proximity sensor and information obtained in advance indicating the spacing of the irregularities on the shaft 52.

[0043] The detection system 60 is not limited to proximity sensors; it may also include other types of devices. For example, the detection system 60 may include an encoder, a sensor for detecting engine noise, or a sensor for detecting engine vibration.

[0044] The speedometer 65 measures the speed of the vessel 2. The speedometer 65 measures the speed using, for example, the Doppler effect. Specifically, the speed measured by the speedometer 65 is the speed relative to the water.

[0045] The engine control device 150 controls the operation of the engine 50. The engine control device 150 determines the fuel injection amount and fuel injection timing based on the actual rotational speed acquired by the determination unit 134. The engine control device 150 controls the operation of the engine 50 so that the fuel injection amount is injected at the determined timing. The engine control device 150 controls the operation of the engine 50 by executing a fuel input amount calculation process, a fuel input control process, and a rotation direction control process.

[0046] The fuel input amount calculation process is a process that calculates the amount of fuel to be input to the prime mover 50 (hereinafter also referred to as "fuel input amount") using a predetermined input amount calculation function based on the target rotational speed and the actual rotational speed. The input amount calculation function is a function that uses the target rotational speed and the actual rotational speed as explanatory variables and the fuel input amount as the dependent variable. The prime mover control device 150 calculates the fuel input amount by executing the fuel input amount calculation process.

[0047] The fuel injection control process controls the degree to which a valve attached to the fuel injection pipe is opened and closed so that the amount of fuel calculated by the fuel injection amount calculation process is injected into the prime mover 50. The fuel injection pipe is a pipe that connects the prime mover 50 to a fuel tank (not shown), and is the pipe through which fuel flows from the fuel tank to the prime mover 50. The prime mover control device 150 injects the amount of fuel from the fuel tank into the prime mover 50 by executing the fuel injection control process.

[0048] The rotation direction control process is a process that controls the rotation direction of the prime mover 50 to the engine rotation direction. The rotation direction control process is a process that switches the rotation direction of the prime mover 50 between forward and reverse rotation by, for example, operating the clutch of the prime mover 50. The prime mover control device 150 controls the rotation direction of the prime mover 50 to the engine rotation direction by executing the rotation direction control process.

[0049] The direction of the torque output by the prime mover 50 corresponds to the direction of rotation of the prime mover 50. Therefore, the direction of the torque when the prime mover 50 is rotating in the forward direction is opposite to the direction of the torque when the prime mover 50 is rotating in the reverse direction. In addition, the power generated by the prime mover 50 is the value obtained by multiplying the magnitude of the torque output by the prime mover 50 by the rotational speed of the prime mover 50.

[0050] The central control unit 130 further comprises an acquisition unit 133 and a determination unit 134. The acquisition unit 133 acquires the detection results from the detection system 60 via the communication unit 122. The determination unit 134 acquires the power measured by the shaft horsepower meter 55 via the communication unit 122. The acquisition unit 133 acquires the ship speed measured by the speedometer 65 via the communication unit 122. The acquisition unit 133 acquires the amount of fuel input calculated by the prime mover control device 150 via the communication unit 122. The acquisition unit 133 acquires the target rotational speed and rotational direction information output by the operation unit 121 via the communication unit 122.

[0051] The determination unit 134 performs rotational speed determination processing. The rotational speed determination processing is a process that determines one of the rotational speeds obtained from the detection system 60 as the actual rotational speed of the prime mover 50, based on at least one of the target rotational speed, state information which is information about the state of the prime mover 50, and the ship speed of the ship 2. Candidates for the actual rotational speed are, for example, the first rotational speed and the second rotational speed. The state information includes, for example, the amount of fuel being added. The state information also includes, for example, the power measured by the shaft horsepower meter 55.

[0052] The control unit 130 outputs the actual rotational speed determined by the determination unit 134 to the prime mover control device 150 via the communication unit 122. The control unit 130 outputs rotational direction information to the prime mover control device 150 via the communication unit 122. The control unit 130 outputs the target rotational speed to the prime mover control device 150 via the communication unit 122. The control unit 130 controls the operation of the output unit 123 to output information to the output unit 123.

[0053] <Flow of energy, etc., in wind power propulsion systems> Figure 3 shows an example of energy flow in the wind power propulsion system 100, along with a comparative example. In Figure 3, the flow of physical materials, the flow of information, and the flow of electricity (an example of energy flow) are indicated by various arrows.

[0054] As shown in Figure 3, in the comparative example (existing system), the wind force is first converted into rotational force to rotate the propeller. Therefore, in the comparative example, the propulsion efficiency is reduced due to the added force conversion. In contrast, the wind-powered propulsion system 100 of this embodiment treats the wind turbine sail as a propeller and uses the lift (Magnus force) generated by the wind-powered sail as the direct propulsion force. In other words, the wind-powered propulsion system 100 of this embodiment uses wind directly as the propulsion force. Therefore, the propulsion efficiency of the wind-powered propulsion system 100 of this embodiment is improved compared to the comparative example.

[0055] In this embodiment of the wind-powered propulsion system 100, wind is received by the wind turbine sail and converted into propulsion. For example, just as a sailing ship receives wind with its sails and converts it into propulsion, a wind turbine sailing ship also directly converts wind into propulsion with the wind turbine sail. The wind-powered propulsion system 100 of this embodiment is characterized by converting wind into propulsion as a sailing ship. Furthermore, in the wind-powered propulsion system 100 of this embodiment, the performance of the wind turbine sail as a sail is superior to that of a general rigid-wing sail.

[0056] <Electric motor> Referring to Figures 2 to 4, the rotation control unit 40 includes an electric motor 41 capable of rotating the wind turbine sail body 111. The electric motor 41 enables both the driving of the rotation of the wind turbine sail body 111 around the rotation axis, and the acceleration and deceleration of the rotation of the wind turbine sail body 111. In other words, the electric motor 41 enables both the driving of the rotation of the blades 10A to 10H around the rotation axis, and the acceleration and deceleration of the rotation of the blades 10A to 10H around the rotation axis.

[0057] <Brake part> The wind propulsion system 100 is further equipped with a braking unit 45 that brakes the rotation of the blades 10A to 10H around the rotation axis when the detection unit 7 detects a wind speed exceeding a threshold. The braking unit 45 reduces the rotation speed of the blades 10A to 10H around the rotation axis during strong winds, thereby reducing lift. Furthermore, by reducing lift during headwinds, induced drag can also be reduced.

[0058] <Energy Storage Section> The wind power propulsion system 100 further includes an energy storage unit 46 that stores the regenerative energy of the electric motor 41 generated when the rotation of the rotating shaft is decelerated. This allows the regenerative energy of the electric motor 41 stored in the energy storage unit 46 to be utilized. For example, the energy storage unit 46 may be configured to include a battery, a capacitor, or the like.

[0059] As mentioned above, while a windmill sail functions as a sail that converts wind power into propulsion, it also functions as a generator that can convert excess energy into electricity when the wind force exceeds the propulsion command. For example, the extracted electricity can be used for propulsion or for general purposes such as lighting.

[0060] <Acquisition part> The wind propulsion system 100 further includes an acquisition unit 133 that acquires the wind speed and direction of the currently occurring wind. The rotation control unit 40 increases the rotation speed of the blades 10A to 10H, which are rotated solely by the acquired wind, using the electric motor 41 if the rotation speed of the blades 10A to 10H, which are rotated only by the currently occurring wind, is below a threshold. For example, if the thrust that can be produced by a wind turbine sail rotating without energy supply using the wind speed and direction of the currently occurring wind is insufficient in response to a thrust command, the thrust can be amplified by increasing the speed with the power of the electric motor 41.

[0061] For example, the rotational speed thresholds for wings 10A to 10H (an example of a rotational speed threshold for wings) are calculated based on the thrust command. For example, the optimal rotational speed may be calculated from the thrust command, and based on the calculation result, the rotational speed of wings 10A to 10H may be increased by the electric motor 41.

[0062] <Relationship between wind turbine sail control and prime mover control> The thrust that a windmill sailing ship can generate without energy is limited. Therefore, the thrust that cannot be generated without energy can be supplemented by the drive mode of the windmill sail (rotation drive of blades 10A to 10H). For example, any thrust insufficient in the windmill sail drive mode can be supplemented by propeller 51 (propeller drive).

[0063] For example, the control unit 130 calculates the optimal rotational speed of the blades 10A to 10H around the rotation axis based on the received thrust command and the wind direction and wind speed detection results detected at the time of receiving the thrust command. For example, when controlling the rotational speed of the blades 10A to 10H, the q-axis current may be controlled by vector control, allowing for seamless control without distinction between driving and braking. For example, the control unit 130 may link the blades 10A to 10H with the propeller 51 and adjust the thrust ratio between the wind turbine sail and the propeller 51 to maximize energy efficiency.

[0064] As described above, the wind propulsion system 100 is a system that converts wind power into thrust. For example, when it receives a thrust command value from the remote control device 120, it calculates the optimal rotation speed of the blades 10A to 10H based on the wind direction and wind speed to produce that thrust. Then, it controls the electric motor 41 to achieve the calculated rotation speed. In this case, the rotation speed includes the direction of rotation. In the case of reverse rotation, it is controlled with a negative speed.

[0065] For example, if the natural thrust of the wind turbine sailboat is insufficient, the propeller 51 is also driven. Depending on the wind direction, if the wind power propulsion system 1 is more efficient than the propeller 51, the electric motor 41 is driven to increase its rotational speed and thus increase thrust. On the other hand, if the propeller 51 is more efficient than the wind power propulsion system 1, the wind power propulsion system 1 is left in a naturally starting state, and the propeller 51 is rotated to generate thrust. It is also possible to drive both the electric motor 41 of the wind power propulsion system 1 and the propeller 51.

[0066] For example, the rotational moment of a ship can be adjusted by arranging multiple windmill sails on the hull. For instance, multiple windmill sails can be arranged fore and aft on the hull, and the rotation speeds of the fore and aft windmill sails can be made different. This can generate a moment by making the forces acting on the ship in the lateral direction different for the fore and aft windmill sails.

[0067] <Rudder control section> Referring to Figure 2, the wind propulsion system 100 further includes a rudder control unit 125 that controls the rudder so as to turn in the opposite direction to the inertial force generated in the opposite direction to the direction in which the rotational speed of the blades 10A to 10H is changed by the rotation control unit 40. This allows the rudder to work in conjunction with the rudder to prevent the hull 3 from rotating, anticipating that torque will act on the hull 3 due to the aforementioned inertial force.

[0068] For example, when changing the rotational speed of the blades 10A to 10H by driving or braking, the rudder may be used in conjunction with the propulsion system. For example, when the electric motor 41 is in a free state and the blades 10A to 10H are rotating freely, it is not necessary to use the rudder in conjunction with the propulsion system. For example, if the brakes are applied or the propulsion system is driven to change the rotational speed of the blades 10A to 10H, torque will act on the hull 3, and the hull 3 may rotate. To prevent this, if only one wind propulsion system 1 is installed, it is advisable to anticipate that torque will act on the hull 3 and use the rudder in conjunction with the propulsion system to prevent the hull 3 from rotating.

[0069] <Wind propulsion device> Referring to Figures 1 and 2, the wind power propulsion device 1 is installed on the ship 2 and functions as a wind turbine sail that generates thrust by receiving wind. In the example shown in the figures, one wind power propulsion device 1 is installed on the forward part (bow) of the hull 3. Note that the installation configuration of the wind power propulsion device 1 (installation location, number of units, etc.) is not limited to the above and can be changed according to the design specifications.

[0070] <Windmill sail body> Figure 4 is a perspective view of the wind turbine sail body 111 in the wind power propulsion device 1 of the first embodiment. Referring also to Figure 4, the wind propulsion device 1 includes a wind turbine sail body 111 that can rotate around a rotation axis RC (a dashed line shown in Figure 4) that extends vertically from the hull 3. The wind turbine sail body 111 includes an assembly 4 consisting of rotating bodies 20A and 20B that can rotate around the axis RC, and a plurality of plate-shaped blades 10A to 10I that are fixed to the rotating bodies 20A and 20B, respectively.

[0071] The rotating bodies 20A and 20B have a frame portion 21 that is formed in an annular shape around a rotation axis RC, and are configured to be rotatable around the rotation axis RC. In the example shown in the figure, the rotating bodies 20A and 20B are composed of a lower plate 20A to which the lower ends of a plurality of wings 10A to 10I are fixed, and an upper plate 20B to which the upper ends of a plurality of wings 10A to 10I are fixed.

[0072] Multiple wings 10A to 10I are each fixed to the frame 21, and are positioned so that imaginary lines connecting their respective ends are parallel in a direction perpendicular to the rotation axis RC. Multiple wings 10A to 10I include a central wing 10A whose imaginary line connecting its respective ends passes through the center of the frame 21. Multiple wings 10A to 10I are positioned so that their ends lie on an imaginary circle centered on the rotation axis RC. The axial direction along the rotation axis RC is the vertical direction.

[0073] When viewed from the vertical, the wings 10A to 10I closest to the center of the frame 21 are positioned such that the length of the imaginary straight line is at least half the diameter of the frame 21. In the example shown, the wings 10A to 10I closest to the center of the frame 21 are those other than the outermost wing. The length of the imaginary straight line is the length from one end of the wing to the other, also known as the chord length. The outermost wing among the wings 10A to 10I may have a chord length of less than half the diameter of the frame 21 (an imaginary circle centered on the rotation axis RC). Note that the chord lengths of the wings 10A to 10I are not limited to the above and can be changed according to the design specifications.

[0074] In the example shown in the figure, the frame 21 (a virtual circle centered on the rotation axis RC) is a perfect circle when viewed from the vertical. Note that the shape of the virtual circle when viewed from the vertical is not limited to the above; it could be an ellipse, an oblong, or a closed ring formed by connecting curves.

[0075] The rotating bodies 20A and 20B have propeller-shaped beam sections 22 that are connected at both ends to the inner circumference of the frame section 21 and connect multiple blades 10A to 10I to each other. In the example shown in the figure, the beam section 22 passes through the center of the frame section 21 and is connected at both ends to the inner circumference of the frame section 21. One beam section 22 is provided on the lower plate 20A and one on the upper plate 20B. Note that the configuration of the beam sections 22 (number and arrangement, etc.) is not limited to the above and can be changed according to the design specifications.

[0076] The central wing 10A is positioned such that a virtual straight line connecting its two ends passes through the center of the frame 21. The central wing 10A has a closed cross-section in cross-sectional view (cross-sectional view intersecting the axial direction along the rotation axis RC). In the example shown in the figure, the central wing 10A has a hollow structure. However, the central wing 10A may also have a solid structure.

[0077] The central wing 10A comprises a central column 71 located at the center of the frame 21 when viewed from the vertical, and a resin wing body 70 that covers the central column 71. The central column 71 is located coaxially with the rotation axis RC. The wing body 70 is made of, for example, FRP (Fiber Reinforced Plastics). The wing body 70 may also be made of metal, wood, other resins, or a composite material of wood and resin.

[0078] In the example shown in the figure, the multiple wings 10A to 10I, including the central wing 10A, are made of FRP (fiber-reinforced plastic). Alternatively, the wings other than the central wing 10A may be made of fabric, with only the central wing 10A being constructed of FRP (fiber-reinforced plastic).

[0079] Of the multiple wings 10A to 10I, wings 10B to 10I, excluding the central wing 10A, are curved radially outward with respect to a virtual straight line. In other words, when viewed from the vertical, wings 10B to 10I outside the central wing 10A are formed in a camber shape that curves radially outward with respect to their respective virtual straight lines. In the example shown in the figure, the eight wings 10B to 10I, excluding the central wing 10A, are formed in a camber shape. Note that wings 10B to 10I other than the central wing 10A may have no camber (elliptical or thin shape).

[0080] In the example in Figure 4, assembly 4 has one stage, but the number of stages in assembly 4 can be changed according to the design specifications, and is not limited to the above. In the example in Figure 1, multiple assemblies 4A to 4C are provided along the vertical direction (for example, three). For example, if there are multiple assemblies 4, A and B, the rotating bodies 20A and 20B of assemblies 4A and 4B may be common. For example, the installation method of the rotating bodies 20A and 20B for multiple assemblies 4 can be changed according to the design specifications. Also, assemblies A and B of 4 may have the same shape, and the rotating bodies 20A and 20B may be bolted together or welded together.

[0081] Figure 5 is a perspective view from above of the first positions of the multiple blades 10A to 10I in the wind propulsion device of the first embodiment. Figure 6 is a perspective view from above of the second positions of the multiple blades 10A to 10I in the wind propulsion device of the first embodiment. In Figures 5 and 6, the upper frame and other components that constitute the assembly are omitted from the illustration.

[0082] Referring to Figures 5 and 6, the multiple wings 10A to 10I have a twisted shape such that, when viewed from the vertical, a first virtual straight line connecting the ends of each of the multiple wings 10A to 10I at a first position on the rotation axis RC (the dashed line shown in the figure) (shown as the first virtual straight line FL1 on the central wing 10A in the figure) and a second virtual straight line connecting the ends of each of the multiple wings 10A to 10I at a second position different from the first position on the rotation axis RC (shown as the second virtual straight line FL2 on the central wing 10A in the figure) intersect.

[0083] In the example shown in the figure, the nine blades are twisted such that a first virtual straight line FL1 at a first position on the rotation axis RC intersects with a second virtual straight line FL2 at a second position on the rotation axis RC when viewed from the vertical. In other words, the nine blades are twisted such that their cross-sections perpendicular to the vertical direction are the same at any position on the rotation axis RC. Note that the twisting pattern (shape, etc.) of the multiple blades 10A to 10I is not limited to the above and can be changed according to the design specifications.

[0084] <Comparison of the effects of the number of wings> Figure 7 is a comparative diagram of the effects of the number of blades (lift, drag, and rotational force). As shown in Figure 7, mesh (finite element model) shapes for 5-bladed, 7-bladed, 9-bladed, 11-bladed, and 13-bladed wind turbines were created, and the effects of the number of blades (lift, drag, and rotational force) were compared through analysis. As a result, it was confirmed that the optimal number of blades is found at the midpoint. Specifically, the maximum lift was achieved with 11 blades, the maximum drag with 7 blades, and the maximum rotational force with 11 blades. Note that the number of blades at which lift and drag are maximized will vary depending on conditions such as the size of the wind turbine sail and the thickness of the blades.

[0085] <Comparison of the effects of different airfoil shapes> Figure 8 is a comparative diagram of the effects of wing shapes (lift, drag, and rotational force). In Figure 8, a cylinder is shown at the center of rotation of the axis of rotation. As shown in Figure 8, elliptical wings, a first camber shape, and a second camber shape were each created using mesh (finite element models), and the effects of the wing shapes (lift, drag, and rotational force) were compared through analysis. The second camber shape has a more pronounced curvature than the first camber shape. As a result, it was confirmed that adding camber increases lift but decreases rotational force.

[0086] <Comparison of the effects of the central wing> Figure 9 is a comparative diagram of the effects of the central wing (lift, drag, and rotational force). As shown in Figure 9, mesh (finite element models) were created for shapes with no center, a central circle, a thin central wing, a thick central wing, and a central wing only, and the effects of the central wing (lift, drag, and rotational force) were compared through analysis. The analysis conditions were: size: diameter of the wind turbine sail body 4m, height 40m, wind speed: 10m / s, and fixed rotation of the wind turbine sail at 54rpm. As a result, it was confirmed that the thin central wing shape was optimal (maximum values ​​for lift, drag, and rotational force).

[0087] <Effects and Effects> As described above, the wind propulsion device 1 according to this embodiment is a wind propulsion device installed on a ship 2 that generates thrust by receiving wind. The wind propulsion device 1 has a frame portion 21 formed in an annular shape with a rotation axis RC, and comprises rotating bodies 20A and 20B that can rotate around the rotation axis RC, and a plurality of blades 10A to 10I that are fixed to the frame portion 21 and arranged so that the imaginary straight lines connecting their respective ends in a direction perpendicular to the rotation axis RC are parallel. The plurality of blades 10A to 10I include a central blade 10A whose imaginary straight line connecting its respective ends passes through the center of the frame portion 21.

[0088] With this configuration, by providing a central wing 10A at the center of the frame 21, the aerodynamic characteristics are improved compared to cases where there is nothing at the center of the frame 21 or where a cylinder is provided.

[0089] The central wing 10A according to this embodiment has a closed cross-section when viewed in cross-section. This configuration improves the rigidity of the central wing 10A compared to the case where it has an open cross-section.

[0090] The central wing 10A according to this embodiment comprises a central column 71 provided at the center of the frame portion 21 when viewed from the vertical direction, and a resin wing body 70 provided so as to cover the central column 71. This configuration allows for a more precise airfoil shape compared to when the central wing 10A is made of fabric, thus improving aerodynamic characteristics.

[0091] Of the multiple wings 10A to 10I according to this embodiment, wings 10B to 10I other than the central wing 10A are curved radially outward with respect to a virtual straight line. This configuration improves lift compared to the case where the wings other than the central wing 10A have no camber (elliptical shape).

[0092] The rotating bodies 20A and 20B according to this embodiment further have propeller-shaped beam portions 22 that are connected at both ends to the inner circumference of the frame portion 21 and connect a plurality of blades 10A to 10I to each other. This configuration improves aerodynamic characteristics compared to the case where multiple wings 10A to 10I are connected to each other by a horizontal bar.

[0093] The multiple wings 10A to 10I according to this embodiment are arranged such that both ends are located on a virtual circle centered on the rotation axis RC. This configuration improves thrust relative to the wing's occupied area.

[0094] In the wind propulsion device 1 according to this embodiment, when viewed from the vertical direction, the blades 10A to 10I on the central side of the frame 21 are arranged such that the length of the imaginary straight line is 1 / 2 or more of the diameter of the frame 21. This configuration significantly enhances the effect of accelerating and decelerating the wind at the front and rear, and the Magnus effect improves the thrust relative to the wing's occupied area.

[0095] The multiple wings 10A to 10I according to this embodiment have a twisted shape such that a first virtual straight line FL1 connecting the ends of each of the multiple wings 10A to 10I at a first position on the rotation axis RC and a second virtual straight line FL2 connecting the ends of each of the multiple wings 10A to 10I at a second position different from the first position on the rotation axis RC intersect when viewed from the vertical direction. With this configuration, the multiple wings 10A to 10I are twisted along the vertical direction, which allows for the generation of airflow along the vertical direction. Therefore, induced drag (e.g., the effect of aspect ratio) can be reduced, and consequently, propulsion efficiency can be improved.

[0096] <Second Embodiment> The wind power propulsion device 201 according to the second embodiment will be described below. In the following description, parts having the same functions as those described in the first embodiment will be given the same names and reference numerals, and a detailed explanation of their functions will be omitted.

[0097] Figure 10 is a perspective view of the wind propulsion device 201 of the second embodiment. Figure 11 is a schematic diagram showing the central blade 210A of the wind propulsion device 201 of the second embodiment. Referring together to Figures 10 and 11, in the wind propulsion device 201 of the second embodiment, the central wing 210A comprises, when viewed from the vertical direction, a central column 71 provided at the center of the frame 21, a pair of support columns 72 provided at both ends of a virtual straight line, and a wing body 270 composed of a cloth stretched between the pair of support columns 72 and the central column 71.

[0098] The rotating bodies 20A and 20B may have both ends connected to the inner circumference of the frame 21 and may also be provided with a horizontal bar 222 (rod-shaped beam) that connects multiple wings 210A to 210I to each other. The rotating bodies 20A and 20B may also be provided with multiple wires 223 (tension structure) that are connected to the frame 21 and each support one of the multiple wings 210A to 210I. The wings 210B to 210I other than the central wing 210A may be made of fabric stretched over the frame 21 and the wires 223.

[0099] In the example shown in the figure, the central column 71 is formed in a cylindrical shape. The pair of support columns 72 are each formed in a cylindrical shape with a smaller diameter than the central column 71. The pair of support columns 72 are formed in the same shape as each other. The fabric of the central wing 210A is formed in a rhomboid shape when viewed from the vertical direction. Note that the configuration (number, configuration, shape, etc.) of the multiple wings 210A to 210I, including the central wing 210A, is not limited to the above and can be changed according to the design specifications.

[0100] The central wing 210A according to this embodiment comprises, when viewed from the vertical direction, a central column 71 provided at the center of the frame portion 21, a pair of support columns 72 provided at both ends of a virtual straight line, and a wing body 270 composed of a cloth stretched between the pair of support columns 72 and the central column 71. This configuration reduces manufacturing costs compared to when the central wing 210A is made of FRP.

[0101] <Third Embodiment> The wind propulsion device according to the third embodiment will be described below. In the following description, parts having the same functions as those described in the second embodiment will be given the same names and reference numerals, and a detailed explanation of their functions will be omitted.

[0102] Figure 12 is a schematic diagram showing the central blade 310A of the wind propulsion device of the third embodiment. As shown in Figure 12, in the wind propulsion device of the third embodiment, the central wing 310A comprises a pair of support columns 72 provided at both ends of a virtual straight line when viewed from the vertical direction, and a wing body 370 made of cloth stretched between the pair of support columns 72.

[0103] In the example shown in the figure, the central wing 310A does not have a central column 71. The pair of support columns 72 are formed in a cylindrical shape. The pair of support columns 72 are formed to be the same shape as each other. The fabric of the central wing 310A is formed in an I-shape (a single straight line) when viewed from the vertical direction. Note that the configuration (number, configuration, shape, etc.) of the multiple wings, including the central wing 310A, is not limited to the above and can be changed according to the design specifications.

[0104] The central wing 310A according to this embodiment comprises a pair of support columns 72 provided at both ends of a virtual straight line when viewed from the vertical direction, and a wing body 370 made of cloth stretched between the pair of support columns 72. This configuration reduces the weight and manufacturing cost of the wind propulsion system compared to a configuration where the central column 71 is located on the central wing 310A.

[0105] <Fourth Embodiment> The following describes the wind propulsion device 401 according to the fourth embodiment. In the following description, parts having the same functions as those described in the first embodiment will be given the same names and reference numerals, and a detailed explanation of their functions will be omitted.

[0106] Figure 13 is a view of the wind power propulsion device 401 of the fourth embodiment from the vertical direction. As shown in Figure 13, in the wind propulsion device 401 of the fourth embodiment, the multiple blades 410A to 410I are vertically extending blades. The frame 21 is made of a rigid body. The multiple blades 10A to 10I are made of materials other than a rigid body.

[0107] The frame 21 is made of a material with higher rigidity than the wings 10A to 10I. The frame 21 is made of, for example, metal, resin (e.g., FRP), wood, or a composite of at least two of these materials. The wings 10A to 10I are made of, for example, fabric.

[0108] Multiple wings 410A to 410I are arranged so as to be symmetric with respect to a center line CL1 that passes through the rotation center of the rotation axis RC and is parallel to the imaginary straight line when viewed from the vertical direction. Multiple wings 410A to 410I are arranged so as to be symmetric with respect to a center line CL2 that passes through the rotation center of the rotation axis RC and is perpendicular to the imaginary straight line when viewed from the vertical direction.

[0109] The frame 21 according to this embodiment is made of a rigid body. The multiple wings 410A to 410I are made of materials other than a rigid body. This configuration reduces manufacturing costs compared to a case where multiple wings 410A to 410I are made of rigid material (e.g., FRP).

[0110] The multiple wings 410A to 410I according to this embodiment are arranged so as to be symmetrical with respect to a center line CL1 that passes through the center of the frame portion 21 and is parallel to a virtual straight line when viewed from the vertical direction. With this configuration, the center of gravity does not change even when rotating, thus suppressing the centrifugal force acting on the ship 2.

[0111] The multiple wings 410A to 410I according to this embodiment are arranged such that, when viewed from the vertical direction, they pass through the center of the frame portion 21 and are symmetrical with respect to a center line CL2 that is perpendicular to the imaginary straight line. With this configuration, the characteristics of the thrust obtained remain unchanged regardless of the direction in which the wings rotate, allowing the aircraft to change its rotation direction to match the wind direction for propulsion.

[0112] <Variation> It should be noted that the technical scope of the present invention is not limited to the embodiments described above, and various modifications can be made without departing from the spirit of the invention.

[0113] The following describes other examples (modifications) of mobile bodies to which the wind propulsion device of the above-described embodiment is installed. Ship sails, airplane wings, rotor blades, wind turbine blades, etc., are all similar in that they generate lift, and the present invention, which has the effect of generating electricity while generating a large lift (Magnus force), can be applied to them. For example, the configuration of the above-described embodiment can also be applied to mobile bodies that move at high speed (e.g., high-speed ships, automobiles, etc.). Furthermore, the wind propulsion device may be applied to the wings of an aircraft, or to airplanes, drones, flying cars, etc. If water resistance is to be ignored, a railway may be used. For example, a wind propulsion device may be installed on a railway running on a local line with low utilization. The mechanism of a windmill sail is not limited to wind and can be applied to other fluids. For example, a ship could be moved across an ocean current to generate electricity (ocean current power generation). Ocean currents are slower but denser than air. The Kuroshio Current moves at about 2 m / s, but considering that it is 1000 times denser than air, this is equivalent to a wind blowing at 20 m / s. In the case of ships, transmitting electricity is difficult, and there are limits to how much electricity can be stored. Therefore, it is possible to build factories that frequently use electricity on ships (factory ships). Examples include hydrogen production and electrolytic aluminum refining. In this case, electricity can be transported directly to the point of demand by ship. For example, wind-powered propulsion systems could be installed on railway containers. In this case, electricity could be supplied to refrigerated containers, eliminating the need to supply power from the pantograph. Furthermore, since the system can be electrically isolated from the railway, the risk of accidents can be reduced. It could also be used as a power source for the brakes of freight cars. Similarly, wind-powered propulsion systems could be installed on truck containers or ship containers.

[0114] Processing may be performed by recording a program for realizing the functions of the control unit according to the above embodiment on a computer-readable recording medium, having a computer system read the program recorded on this recording medium, and executing it. Furthermore, the term "computer system" as used herein may include an operating system (OS) or hardware such as peripheral devices. Furthermore, "computer-readable recording media" refers to writable non-volatile memory such as flexible disks, magneto-optical disks, ROM (Read Only Memory), and flash memory, portable media such as DVDs (Digital Versatile Discs), and storage devices such as hard disks built into computer systems.

[0115] Furthermore, "computer-readable recording media" also includes volatile memory (such as DRAM (Dynamic Random Access Memory)) within information processing devices or client computer systems that retain programs for a certain period of time when programs are transmitted via networks such as the Internet or communication lines such as telephone lines. Furthermore, the above program may be transmitted from a computer system that stores the program in a memory device or the like to another computer system via a transmission medium or by transmission waves within the transmission medium. Here, the "transmission medium" used to transmit the program refers to a medium that has the function of transmitting information, such as a network (communication network) like the Internet or a communication line (communication line) like a telephone line. Furthermore, the above program may be intended to implement some of the functions described above. Moreover, the above program may be a so-called differential file (differential program) that can implement the functions described above in combination with a program already recorded in the computer system.

[0116] Furthermore, it is possible to replace the components in the above-described embodiments with well-known components without departing from the spirit of the present invention. Also, the above-described modifications may be combined. Among the embodiments disclosed herein, those composed of multiple objects may be integrated, and conversely, those composed of a single object may be divided into multiple objects. Whether or not they are integrated, the invention can be constructed in a way that achieves its objective. In the embodiments disclosed herein, those in which multiple functions are provided in a distributed manner may have some or all of those multiple functions integrated into a single unit, and conversely, those in which multiple functions are integrated may have some or all of those functions provided in a distributed manner. Whether the functions are integrated or distributed, the configuration should be such that the objective of the invention can be achieved. [Explanation of symbols]

[0117] 1, 201, 401…wind propulsion device, 2…ship (moving body), 10A~10I, 210A~210I, 410A~410I…wing, 10A, 210A, 310A…central wing, 20A, 20B…rotating body, 21…frame, 22…beam, 70, 270, 370…wing body, 71…central column, 72…support column, CL1, CL2…centerline, FL1, FL2…virtual straight line, RC…rotation axis

Claims

1. A wind-powered propulsion device installed on a moving object that generates thrust by receiving wind, A rotating body having a frame portion formed in an annular shape around a rotation axis, and being rotatable around the rotation axis, The system comprises a plurality of wings, each fixed to the frame, such that a virtual straight line connecting each of their ends is parallel to the frame in a direction perpendicular to the axis of rotation, The plurality of wings include a central wing, the virtual straight line connecting each of its ends passing through the center of the frame. Wind propulsion device.

2. The central wing has a closed cross-section when viewed in a cross-sectional view intersecting the axial direction along the axis of rotation. The wind propulsion device according to claim 1.

3. The aforementioned frame is made of a rigid body, The aforementioned multiple wings are composed of materials other than rigid bodies. The wind propulsion device according to claim 1.

4. The central wing, when viewed from the axial direction along the axis of rotation, A central column is provided at the center of the frame, The system comprises a resin wing body provided to cover the central column, The wind propulsion device according to claim 1 or 2.

5. The central wing, when viewed from the axial direction along the axis of rotation, A central column is provided at the center of the frame, A pair of support columns are provided at both ends of the aforementioned imaginary straight line, The wing body comprises the pair of support columns and the cloth stretched over the central column, The wind propulsion device according to claim 1 or 2.

6. The central wing, when viewed from the axial direction along the axis of rotation, A pair of support columns are provided at both ends of the aforementioned imaginary straight line, The wing comprises a wing body made of cloth stretched over the pair of support struts, The wind propulsion device according to claim 1 or 2.

7. Of the plurality of wings, the wings other than the central wing are curved radially outward with respect to the virtual straight line. A wind propulsion device according to any one of claims 1 to 3.

8. The rotating body further has propeller-shaped beam sections connected at both ends to the inner circumference of the frame section and connecting the plurality of blades together. A wind propulsion device according to any one of claims 1 to 3.

9. The plurality of wings are arranged such that both ends are located on a virtual circle centered on the axis of rotation. A wind propulsion device according to any one of claims 1 to 3.

10. The plurality of wings are arranged such that, when viewed from the axial direction along the axis of rotation, they are symmetrical with respect to a center line that passes through the center of the frame and is parallel to the imaginary straight line. A wind propulsion device according to any one of claims 1 to 3.

11. The plurality of wings are arranged such that, when viewed from the axial direction along the axis of rotation, they pass through the center of the frame and are symmetric with respect to a center line perpendicular to the imaginary straight line. A wind propulsion device according to any one of claims 1 to 3.

12. Viewed from the axial direction along the rotation axis, the wings on the central side of the frame are arranged such that the length of the imaginary straight line is 1 / 2 or more of the diameter of the frame. A wind propulsion device according to any one of claims 1 to 3.

13. The plurality of wings are twisted in such a way that a first imaginary straight line connecting the ends of each of the plurality of wings at a first position on the axis of rotation intersects with a second imaginary straight line connecting the ends of each of the plurality of wings at a second position different from the first position on the axis of rotation when viewed from the axial direction along the axis of rotation. A wind propulsion device according to any one of claims 1 to 3.

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