Patent Publication Number: US-2018030887-A1

Title: Multi-shaft power source unmanned flight equipment

Description:
TECHNICAL FIELD 
     The present invention belongs to the technical field of unmanned aerial vehicles, and particularly relates to multi-shaft power source unmanned flight equipment. 
     BACKGROUND OF THE INVENTION 
     Unmanned aerial vehicles (UAVs) are unmanned airplanes mainly remotely controlled by radio or controlled by their own programs. 
     The UAVs in the prior art are mostly electric ones and mainly adopt batteries, electronic speed controllers, motors, flight controllers, propellers and the like as main devices, and the flight of the UAVs is controlled by changing the rotating speeds of the propellers. However, the duration of the electric UAVs is very short due to the limitation of battery energy density, so the UAVs have the defect of poor endurance; and the method of prolonging the duration by simply increasing the quantity of batteries also greatly reduces the loading capacity of the UAVs. 
     SUMMARY OF THE INVENTION 
     The present invention provides multi-shaft power source unmanned flight equipment, which is provided with a power device, burns a combustion material injected in the power device to generate mechanical kinetic energy, and then provides power for the rotation of rotors, thereby replacing the traditional electric flight mode of supplying power by batteries or prolonging the duration by increasing the quantity of batteries, and at least having the technical characteristics of long duration and strong loading capacity. 
     The present invention provides multi-shaft power source unmanned flight equipment, including a frame, a plurality of rotor sets and a power device, wherein each rotor set includes a plurality of rotors, and each rotor set is rotatably fixed on the frame, so that the rotors in each rotor set can rotate relative to the frame; the power device is fixed on the frame, and correspondingly movably connected with each rotor set respectively, so that mechanical transmission can be realized between the power device and each rotor set; and the rotors in each rotor set correspondingly connected with the power device are driven to rotate via mechanical kinetic energy generated by burning a combustion material injected in the power device. 
     Optionally, the multi-shaft power source unmanned flight equipment further includes a belt transmission device, which is fixed on the frame and correspondingly movably connects the power device with each rotor swing set, thereby realizing mechanical transmission between the power device and each rotor set via the belt transmission device. 
     Optionally, the quantity of the rotor sets is m, and the m is an even number more than or equal to 2; and the m rotor sets include m/2 first rotor sets and m/2 second rotor sets, the m/2 first rotor sets are respectively movably connected with the power device, the m/2 second rotor sets are respectively movably connected with the power device, and the mechanical transmission between the m/2 first rotor sets and the power device is independent from that between the m/2 second rotor sets and the power device. 
     Optionally, the power device includes a first power source, a second power source and a starter, wherein the first power source is provided with a first shaft, and the m/2 first rotor sets are respectively movably connected with the first shaft; the second power source is provided with a second shaft, and the m/2 second rotor sets are respectively movably connected with the second shaft; the starter is movably connected with the first shaft and the second shaft respectively, and is used to start the first shaft and the second shaft to rotate; the started rotating first shaft compresses the combustion material injected in the first power source to generate mechanical kinetic energy, the mechanical kinetic energy drives the first shaft to rotate continuously, and then the first shaft drives each rotor in the m/2 first rotor sets to rotate; and the started rotating second shaft compresses the combustion material injected in the second power source to generate mechanical kinetic energy, the mechanical kinetic energy drives the second shaft to rotate continuously, and then the second shaft drives each rotor in the m/2 second rotor sets to rotate 
     Optionally, the first power source further includes a first shaft gear; the second power source further includes a second shaft gear; the power device further includes a starter gear; the first shaft gear is sleeved on the first shaft and rotates synchronously with the first shaft, and the second shaft gear is sleeved on the second shaft and rotates synchronously with the second shaft; and the starter gear is connected with the starter, the starter drives the starter gear to rotate, and the starter gear is correspondingly engaged with the first shaft gear and the second shaft gear respectively. 
     Optionally, the first shaft and the second shaft are parallel, and have opposite rotating directions. 
     Optionally, the multi-shaft power source unmanned flight equipment further includes a first belt transmission device and a second belt transmission device, wherein the first belt transmission device is fixed on the frame and correspondingly movably connected with the m/2 first rotor sets respectively; the second belt transmission device is fixed on the frame and correspondingly movably connected with the m/2 second rotor sets respectively; the first belt transmission device is sleeved on the first shaft, and the rotation of the first shaft drives the first belt transmission device to carry out transmission so as to drive each rotor in the m/2 first rotor sets to rotate; and the second belt transmission device is sleeved on the second shaft, and the rotation of the second shaft drives the second belt transmission device to carry out transmission so as to drive each rotor in the m/2 second rotor sets to rotate. 
     Optionally, the first belt transmission device includes a first transmission shaft, m/2 second transmission shafts, a first conveying belt, a first motor and a second motor, wherein the first transmission shaft includes a first fixed end and a first bevel gear end, and the first bevel gear end is of a bevel gear structure; each second transmission shaft includes a third bevel gear end and a fourth bevel gear end, and both the third bevel gear end and the fourth bevel gear end are of a bevel gear structure; the first conveying belt includes a first sleeved end and a second sleeved end; the first motor is fixed on the first shaft and rotates synchronously with the first shaft, and the first conveying belt is sleeved on the first motor via the first sleeved end; the second motor is fixed at the first fixed end and rotates synchronously with the first transmission shaft, and the first conveying belt is sleeved on the second motor via the second sleeved end; the m/2 first rotor sets correspond to the m/2 second transmission shafts one by one, and are correspondingly engaged with the m/2 fourth bevel gear ends of the m/2 second transmission shafts via the bevel gear structures respectively; and the m/2 second transmission shafts are distributed symmetrically by taking the first transmission shaft as a central vertical shaft, the m/2 third bevel gear ends of the m/2 second transmission shafts are engaged with the first bevel gear end to convert the vertical rotation of the first transmission shaft to the transverse rotation of the second transmission shafts, and then each rotor in the m/2 first rotor sets is driven to rotate by the transverse rotation of the second transmission shafts; 
     and/or 
     the second belt transmission device includes a third transmission shaft, m/2 fourth transmission shafts, a second conveying belt, a third motor and a fourth motor, wherein the third transmission shaft includes a second fixed end and a fifth bevel gear end, and the fifth bevel gear end is of a bevel gear structure; each fourth transmission shaft includes a sixth bevel gear end and a seventh bevel gear end, and both the sixth bevel gear end and the seventh bevel gear end are of a bevel gear structure; the second conveying belt includes a third sleeved end and a fourth sleeved end; the third motor is fixed on the second shaft and rotates synchronously with the second shaft, and the second conveying belt is sleeved on the third motor via the third sleeved end; the fourth motor is fixed at the second fixed end and rotates synchronously with the third transmission shaft, and the second conveying belt is sleeved on the fourth motor via the fourth sleeved end; the m/2 second rotor sets correspond to the m/2 fourth transmission shafts one by one, and are correspondingly engaged with the m/2 seventh bevel gear ends of the m/2 fourth transmission shafts via the bevel gear structures respectively, the m/2 fourth transmission shafts are distributed symmetrically by taking the third transmission shaft as a central vertical shaft, the m/2 sixth bevel gear ends of the m/2 fourth transmission shafts are engaged with the fifth bevel gear end to convert the vertical rotation of the third transmission shaft to the transverse rotation of the fourth transmission shafts, and then each rotor in the m/2 second rotor sets is driven to rotate by the transverse rotation of the fourth transmission shafts. 
     Optionally, the quantity of rotors in each rotor set is n, and the n is an integer more than or equal to 2. 
     Optionally, the m is 4. 
     Advantages 
     In the multi-shaft power source unmanned flight equipment provided by the present invention, power is provided for flight of the unmanned flight equipment by the power device with oil drive characteristics, i.e., the power device is fixed on the frame of the unmanned flight equipment, the power device is correspondingly movably connected with each rotor set respectively, so that mechanical transmission can be realized between the power device and each rotor set, and mechanical kinetic energy is generated by burning a combustion material (e.g., a gas combustion material, a liquid combustion material, a gas-liquid mixed combustion material, etc.) pre-injected in the power device to drive the rotors in each rotor set correspondingly connected with the power device to rotate. The unmanned flight equipment replaces the traditional electric unmanned aerial vehicle adopting electric modes such as batteries, electronic speed controllers and the like to supply power and provide power for the rotation of the rotors, and the unmanned flight equipment does not need to prolong the duration by increasing the quantity of batteries along with the reduction of the loading capacity of the unmanned aerial vehicle, and has the characteristics of long duration and strong loading capacity. 
    
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
       To illustrate the technical solutions in the embodiments of the present invention or in the prior art more clearly, a brief introduction on the accompanying drawings which are needed in the embodiments is given below. Apparently, the accompanying drawings in the description below are merely some of the embodiments of the present invention, based on which other drawings may be obtained by those of ordinary skill in the art without any creative effort. 
         FIG. 1  is a schematic diagram  1  of an overall structure of multi-shaft power source unmanned flight equipment provided by an embodiment of the present invention; 
         FIG. 2  is a schematic diagram  2  of the overall structure of the multi-shaft power source unmanned flight equipment provided by the embodiment of the present invention; 
         FIG. 3  is a schematic diagram  3  of the overall structure of the multi-shaft power source unmanned flight equipment provided by the embodiment of the present invention; 
         FIG. 4  is a schematic diagram of an overall structure of a power device provided by an embodiment of the present invention; 
         FIG. 5  is a front view of the overall structure of the power device provided by the embodiment of the present invention; 
         FIG. 6  is a front view of the exploded structure of the power device provided by the embodiment of the present invention; 
         FIG. 7  is a front view of a partial structure of a first belt transmission device provided by an embodiment of the present invention; 
         FIG. 8  is a sectional view of the partial structure of the first belt transmission device provided by the embodiment of the present invention; 
         FIG. 9  is a front view of a partial structure of a second belt transmission device provided by an embodiment of the present invention; 
         FIG. 10  is a sectional view of the partial structure of the second belt transmission device provided by the embodiment of the present invention; 
         FIG. 11  is a front view of an overall structure of a variable pitch device provided by an embodiment of the present invention; and 
         FIG. 12  is a schematic diagram of the overall structure of the variable pitch device provided by the embodiment of the present invention 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     The present invention provides multi-shaft power source unmanned flight equipment, wherein power is provided for flight of the unmanned flight equipment by a power device with oil drive characteristics, i.e., the power device is fixed on a frame of the unmanned flight equipment, the power device is correspondingly movably connected with each rotor set respectively, so that mechanical transmission can be realized between the power device and each rotor set, and mechanical kinetic energy is generated by burning a combustion material (e.g., a gas combustion material, a liquid combustion material, a gas-liquid mixed combustion material, etc.) pre-injected in the power device to drive rotors in each rotor set correspondingly connected with the power device to rotate. The unmanned flight equipment replaces the traditional electric unmanned aerial vehicle adopting electric modes such as batteries, electronic speed controllers and the like to supply power and provide power for the rotation of the rotors, and the unmanned flight equipment does not need to prolong the duration by increasing the quantity of batteries along with the reduction of the loading capacity of the unmanned aerial vehicle, and has the characteristics of long duration and strong loading capacity. 
     A clear and complete description of the technical solutions in the embodiments of the present invention will be described below, in combination with the accompanying drawings in the embodiments of the present invention, to support the technical problems to be solved by the present invention. Apparently, the embodiments described are merely a part, but not all, of the embodiments of the present invention. All of other embodiments, obtained by those of ordinary skill in the art based on the embodiments of the present invention, fall into the protection scope of the present invention. The keyword “and/or” involved in the embodiments expresses situations of “and” and “or”, in other words, A and/or B mentioned in the embodiments of the present invention expresses situations of A and B and A or B, and describes three states between A and B, e.g., A and/or B expresses: only including A but not including B, only including B but not including A, and including A and B. 
     Meanwhile, in the embodiments of the present invention, when one component is referred to be “fixed” on another component, it can be directly fixed on the other component or there can be an intermediate component. When one component is referred to be “connected” to another component, it can be directly connected to the other component or there may be an intermediate component. When one component is referred to be “arranged” on another component, it can be directly arranged on the other component or there may be an intermediate component. The terms “vertical”, “horizontal”, “left”, “right” and similar expressions used in the embodiments of the present invention are just for the purpose of description, rather than limiting the present invention. 
     Referring to  FIGS. 1-2 , an embodiment of the present invention provides multi-shaft power source unmanned flight equipment, at least including a frame  1 , a plurality of rotor sets  2  and a power device  3 . Each rotor set  2  includes a plurality of rotors  21 , and each rotor set  2  is rotatably fixed on the frame  1 , so that the rotors  21  in each rotor set  2  can rotate relative to the frame  1 ; and the power device  3  is fixed on the frame  1 , and correspondingly movably connected with the each rotor set  2  respectively, so that mechanical transmission can be realized between the power device  3  and each rotor set  2 . Mechanical kinetic energy is generated by burning a combustion material pre-injected in the power device  3  to drive the rotors  21  in each rotor set  2  correspondingly connected with the power device  3  to rotate. 
     Specifically, the frame  1  in the embodiment of the present invention is a supporting platform for the overall structure of the unmanned flight equipment, and is used for supporting the plurality of rotor sets  2 , the power device  3  and the like fixedly mounted on the unmanned flight equipment. Each of the plurality of rotor sets  2  is rotatably fixed on the frame  1 , wherein how each rotor set  2  is rotatably fixed on the frame  1  is not limited by the embodiment of the present invention, the rotor set  2  can be directly fixed on the frame  1 , so that the rotor set  2  can rotate relative to the frame  1 , certainly, the rotor set  2  can be movably fixed on the frame  1  via a separate movable device, so that the rotor set  2  can rotate relative to the frame  1 , and all situations finally enabling the rotors  21  in each rotor set  2  to rotate relative to the frame  1  are applicable to the present invention. 
     There may be multiple rotor sets  2  in the embodiment of the present invention, and it could be understood that since each rotor set  2  includes a plurality of rotors  21 , the more the rotor sets  2  are, the more the rotors  21  are. The quantity of the rotor sets  2  in the embodiment of the present invention may be m, and the m is an even number more than or equal to 2. The quantity m of the rotor sets  2  is limited to an even number more than or equal to 2 mainly based on the overall structural layout of the unmanned flight equipment provided by the embodiment of the present invention, thereby improving the stability of the equipment in the flight process. For example, the m rotor sets  2  may be equally divided into first sets and second sets, i.e., include m/2 first rotor sets and m/2 second rotor sets, the m/2 first rotor sets are respectively movably connected with the power device  3 , the m/2 second rotor sets are respectively movably connected with the power device  3 , and the mechanical transmission between the m/2 first rotor sets and the power device is independent from that between the m/2 second rotor sets and the power device. The m/2 first rotor sets and the m/2 second rotor sets are symmetrically distributed on two sides of the power device  3  serving as a central symmetric point. 
     In combination with  FIG. 2  and referring to  FIGS. 3-6 , the power device  3  at least includes a first power source  32 , a second power source  33  and a starter  34 . The first power source  32  is provided with a first shaft  321 , and the m/2 first rotor sets are respectively movably connected with the first shaft  321 . The second power source  33  is provided with a second shaft  331 , and the m/2 second rotor sets are respectively movably connected with the second shaft  331 . The starter  34  is movably connected with the first shaft  321  and the second shaft  331  respectively, and is used to start the first shaft  321  and the second shaft  331  to rotate. It should be noted that the first shaft  321  of the first power source  32  is used for driving the m/2 first rotor sets to rotate, and the second shaft  331  of the second power source  33  is used for driving the m/2 second rotor sets to rotate. 
     Specifically, the starter  34  serving as a starting component starts the first shaft  321  and the second shaft  331  to rotate firstly, the started rotating first shaft  321  compresses the combustion material injected in the first power source  32 , the combustion material is exploded and burnt, the thermal energy is converted into mechanical kinetic energy, the first shaft  321  is driven to rotate continuously under the impact of rapidly expanding air pressure, and then the first shaft  321  drives each rotor in the m/2 first rotor sets to rotate, thereby entering a normal cyclic driving program of the first power source  32 , the first shaft  321  and the m/2 first rotor sets. The started rotating second shaft  331  compresses the combustion material injected in the second power source  33 , the combustion material is exploded and burnt, the thermal energy is converted into mechanical kinetic energy, the second shaft  331  is driven to rotate continuously under the impact of rapidly expanding air pressure, and then the second shaft  331  drives each rotor in the m/2 second rotor sets to rotate, thereby entering a normal cyclic driving program of the second power source  33 , the second shaft  331  and the m/2 second rotor sets. It should be noted that after the starter  34  serving as a starting component in the embodiment of the present invention starts the first shaft  321  and the second shaft  331  to rotate, the starter  34  is automatically separated from the first shaft  321  and the second shaft  331  and stops working, and the energy inside the first power source  32  and the second power source  33  themselves is converted into thermal energy and mechanical energy to provide power for the rotation of the first shaft  321  and the second shaft  331 . 
     How the starter  34  starts the first shaft  321  and the second shaft  331  to rotate is not limited by the embodiment of the present invention, a mechanical transmission relation may be directly established between the starter  34  and the first shaft  321  and between the starter  34  and the second shaft  331 , for example, a plurality of teeth are arranged on the side walls of the first shaft  321  and the second shaft  331 , a rotating shaft of the starter  34  is directly engaged with the plurality of teeth on the side walls of the first shaft  321  and the second shaft  331 , and then the first shaft  321  and the second shaft  331  are driven to rotate by the rotation of the rotating shaft of the starter  34 . As another example, a mechanical arm capable of respectively rotating around the first shaft  321  or the second shaft  331  is respectively arranged on the side walls of the first shaft  321  and the second shaft  331 , the two mechanical arms are respectively connected with the starter  34 , the starter  34  drives the two mechanical arms to act respectively, and then the two mechanical arms correspondingly drive the first shaft  321  or the second shaft  331  connected therewith to rotate. 
     As another example, a first shaft gear  322  may be directly added in the first power source  32 , a second shaft gear  332  is added in the second power source  33 , and a starter gear  31  is added in the power device. The first shaft gear  322  is sleeved on the first shaft  321  to rotate synchronously with the first shaft  321 , and the second shaft gear  332  is sleeved on the second shaft  331  to rotate synchronously with the second shaft  331 . Meanwhile, the starter gear  31  is connected with the rotating shaft of the starter  34 , the starter  34  drives the starter gear  31  to rotate, and the starter gear  31  is correspondingly engaged with the first shaft gear  322  and the second shaft gear  332  respectively to ensure that the first shaft gear  322  and the second shaft gear  332  can rotate synchronously in the rotating process of the starter gear  31 . Certainly, the connection mode between the first shaft gear  322  and the first shaft  321  and the connection mode between the second shaft gear  332  and the second shaft  331  may be diverse, for example, the first shaft gear  322  and the first shaft  321  may be connected by welding, and the second shaft gear  332  and the second shaft  331  may be connected by welding. As another example, the first shaft gear  322  and the first shaft  321  may be integrated, and the second shaft gear  332  and the second shaft  331  may also be integrally connected. In the embodiment of the present invention, the connection modes are available as long as they can achieve the technical effects that the first shaft gear  322  rotates synchronously with the first shaft  321  and the second shaft gear  332  rotates synchronously with the second shaft  331 . Similarly, in the presence of the two shaft gears (the first shaft gear  322  and the second shaft gear  332 ), there may be two starter gears  31  and even two starters  34 . That is, the first shaft gear  322  is matched with one starter gear  31  and one starter  34 , and the second shaft gear  332  is matched with the other starter gear  31  and the other starter  34 , or the first shaft gear  322  is matched with one starter gear  31 , the second shaft gear  332  is matched with the other starter gear  31 , and one starter  34  simultaneously starts the two starter gears  31  to rotate, etc., and all situations finally enabling the first shaft  321  and the second shaft  331  to be driven to rotate are applicable to the present invention. 
     Altogether, as mentioned above, how the starter  34  starts the first shaft  321  and the second shaft  331  to rotate is not limited by the embodiment of the present invention, at least the three starting structures and modes described above may be adopted, certainly, other starting structures and modes not limited to the embodiment of the present invention may also be adopted, are applicable to the present invention as long as the starter can normally start the first shaft  321  and the second shaft  331  to rotate, and are thus not redundantly described herein. However, it is worth mentioning that the first shaft  321  and the second shaft  331  in the embodiment of the present invention are parallel and have opposite rotating directions. 
     Further, as for the power device  3 , in order to simplify the design of the internal structure and reduce the industrial manufacturing cost, the first power source  32  may be a first single-cylinder engine, and the second power source  33  may be a second single-cylinder engine. The power device  3  may further include a connecting plate  35 . 
     The first single-cylinder engine is provided with the first shaft  321 , and the combustion material is injected in the cylinder of the first single-cylinder engine; the second single-cylinder engine is provided with the second shaft  331 , and the combustion material is injected in the cylinder of the second single-cylinder engine; the first single-cylinder engine penetrates through the connecting plate  35  via the first shaft  321 , and the second single-cylinder engine penetrates through the connecting plate  35  via the second shaft  331 , so that the connecting plate  35  connects the first single-cylinder engine with the second single-cylinder engine into a whole. 
     Meanwhile, the power device  3  further includes a first carburetor  36  and a second carburetor  37 , the first carburetor  36  is connected with the oil inlet of the first single-cylinder engine, and the second carburetor  37  is connected with the oil inlet of the second single-cylinder engine. In this case, the combustion material (e.g., liquid combustion material) in different states is converted into a gas combustion material under the action of the first carburetor  36  and/or the second carburetor  37 , which is prepared for explosion and burning of the combustion material in the first single-cylinder engine and/or the second single-cylinder engine. It could be understood that the combustion material in the cylinder of the first single-cylinder engine is injected via the first carburetor  36 , and the combustion material in the cylinder of the second single-cylinder engine is injected via the second carburetor  37 . 
     It should be noted that the connecting plate  35  connects the first single-cylinder engine with the second single-cylinder engine into a whole to form a double-shaft aero-engine (the power device  3 ) in the embodiment of the present invention, wherein the connecting plate  35  may include a first hood  351  and a second hood  352 . The first hood  351  and the second hood  352  are detachably connected with each other, an accommodating space  353  is formed between the first hood  351  and the second hood  352 , and the first shaft gear  322 , the second shaft gear  332  and the starter gear  31  are placed in the accommodating space  353 . Moreover, the starter  34  penetrates through the first hood  351  or the second hood  352  to be connected with the starter gear  31 . 
     It could be understood that the first shaft  321  of the first single-cylinder engine is sleeved with the first shaft gear  322 , and the second single-cylinder engine is sleeved with the second shaft gear  332 . The starter  34  starts the first shaft gear  322  and the second shaft gear  332  to rotate first via the starter gear  31 , then the first shaft  321  and the second shaft  331  are driven to rotate (the rotating directions of the both are opposite), the started rotating first shaft  321  compresses the combustion material injected in the cylinder of the first single-cylinder engine, the combustion material is exploded and burnt, the thermal energy is converted into mechanical kinetic energy, the first shaft  321  is driven to rotate continuously under the impact of rapidly expanding air pressure, and then the first shaft  321  drives each rotor in the m/2 first rotor sets to rotate, thereby entering a normal cyclic driving program of the first single-cylinder engine, the first shaft  321  and the m/2 first rotor sets. The started rotating second shaft  331  compresses the combustion material injected in the second power source  33 , the combustion material is exploded and burnt, the thermal energy is converted into mechanical kinetic energy, the second shaft  331  is driven to rotate continuously under the impact of rapidly expanding air pressure, and then the second shaft  331  drives each rotor in the m/2 second rotor sets to rotate, thereby entering a normal cyclic driving program of the second single-cylinder engine, the second shaft  331  and the m/2 second rotor sets. It is worth mentioning that the internal principles of the first single-cylinder engine and the second single-cylinder engine (e.g., the started rotating first shaft  321  compresses the combustion material injected in the cylinder of the first single-cylinder engine, the combustion material is exploded and burnt, the thermal energy is converted into mechanical kinetic energy, the first shaft  321  is driven to rotate continuously under the impact of rapidly expanding air pressure) are the working principles of engines in the prior art, and are thus not redundantly described herein. The present invention is innovative in how the first single-cylinder engine and the second single-cylinder engine form a double-cylinder opposite double-output-shaft engine via the connecting plate  35 , the starter  34  and/or the starter gear  31  and in that the double-cylinder opposite double-output-shaft engine is applied to oil driven variable pitch multi-rotor flight equipment, so that the equipment is simple in structure, reliable and portable and simultaneously has the technical features of long duration and high loading capacity. 
     Further, in order to cool the power device  3  provided by the embodiment of the present invention in time and avoid the influence of too high temperature on its normal use, the embodiment of the present invention preferably includes an air cooling system  38 . The air cooling system  38  is fixed on the first power source  32  and the second power source  33 , so that external cold air is sucked into the power device  3  via the air cooling system  38  and then flows through the first power source  32  and/or the second power source  33  to cool the first power source  32  and/or the second power source  33 . 
     Specifically, continuously referring to  FIGS. 4-5 , the air cooling system  38  may include a cover  381 , a first centrifugal fan  382  and a second centrifugal fan  383 . The first centrifugal fan  382  is movably connected with the first shaft  321 , and the first shaft  321  drives the first centrifugal fan  382  to rotate; the second centrifugal fan  383  is movably connected with the second shaft  331 , and the second shaft  331  drives the second centrifugal fan  383  to rotate. Besides, the first centrifugal fan  382 , the second centrifugal fan  383 , the first power source  32  and the second power source  33  are arranged in the cover  381 , and the rotating first centrifugal fan  382  and/or the second centrifugal fan  383  drive the cold air to flow in the cover  381  to cool the first power source  32  and/or the second power source  33 . 
     In the embodiment of the present invention, the first centrifugal fan  382  and the second centrifugal fan  383  are used for sucking in fluid in the axial directions thereof and then throwing out the fluid in the circumferential directions by using the centrifugal force thereof, it could be understood as throwing into the cover  381 , and the first power source  32  and the second power source  33  are thus air-cooled. Normal operation of the first power source  32  and the second power source  33  is prevented from being influenced by too high temperature in the cover  381  due to long working time and continuous heat emission of the first power source  32  and the second power source  33 , and the characteristic of high safety performance is achieved. 
     Certainly, in the embodiment of the present invention, there are two power sources, e.g., the first power source  32  and the second power source  33 . There are also two centrifugal fans matched with the power sources, e.g., the first centrifugal fan  382  and the second centrifugal fan  383 . There are also two shafts matched with the power sources, e.g., the first shaft  321  and the second shaft  331 . However, the specific quantity of the power sources is not limited. In other words, designing three, four, five or more power sources according to actual operating requirements is also applicable to the present invention, as long as three, four, five or more centrifugal fans and shafts corresponding to the power sources are also designed. The remaining structures are adaptively modified, and these modifications fall into the protection scope of the present invention. 
     Preferably, the cover  381  in the embodiment of the present invention may include a first side wall  3811 , a second side wall  3812  and an air inlet plate  3813 . The air inlet plate  3813  is provided with a first air inlet  3813   a  and a second air inlet  3813   b , the end of the first side wall  3811  and the end of the second side wall  3812  are respectively fixedly connected with the air inlet plate  3813  to form the cover  381  with a U-shaped structure, and the first side wall  3811  is parallel to the second side wall  3812 . The first power source  32  and the second power source  33  are arranged in the U-shaped groove of the U-shaped structure, the rotating first centrifugal fan  382  drives the cold air to flow into the cover  381  via the first air inlet  3813   a , and the rotating second centrifugal fan  383  drives the cold air to flow into the cover  381  via the second air inlet  3813   b.    
     In the embodiment of the present invention, as for the mechanical transmission between the rotor sets  2  and the power device  3 , a belt transmission device  4  is fixed on the frame  1 , and correspondingly movably connects the power device  3  with each rotor set  2 , so that the mechanical transmission can be realized between the power device  3  and each rotor set  2  via the belt transmission device  4 . Specifically, in combination with  FIGS. 2-3  and referring to  FIGS. 7-10 , the belt transmission device  4  may be specifically divided into a first belt transmission device  41  and a second belt transmission device  42 . 
     The first belt transmission device  41  is fixed on the frame  1 , and is correspondingly movably connected with the m/2 first rotor sets respectively. The second belt transmission device  42  is fixed on the frame  1 , and is correspondingly movably connected with the m/2 second rotor sets respectively. One end of the first belt transmission device  41  is sleeved on the first shaft  321 , the other end of the first belt transmission device  41  is sleeved on rotor shafts of the rotors in the m/2 first rotor sets, and the rotation of the first shaft  321  drives the first belt transmission device  41  to carry out transmission so as to drive each rotor in the m/2 first rotor sets to rotate. One end of the second belt transmission device  42  is sleeved on the second shaft  331 , the other end of the second belt transmission device  42  is sleeved on the rotor shafts of the rotors in the m/2 second rotor sets, and the rotation of the second shaft  331  drives the second belt transmission device  42  to carry out transmission so as to drive each rotor in the m/2 second rotor sets to rotate. 
     More specifically, the first belt transmission device  41  at least may include a first transmission shaft  411 , m/2 second transmission shafts  412 , a first conveying belt  413 , a first motor  414  and a second motor  415 . The first transmission shaft  411  includes a first fixed end  4111  and a first bevel gear end  4112 , and the first bevel gear end  4112  is of a bevel gear structure. Each second transmission shaft  412  includes a third bevel gear end  4121  and a fourth bevel gear end  4122 , and both the third bevel gear end  4121  and the fourth bevel gear end  4122  are of a bevel gear structure. The first conveying belt  413  includes a first sleeved end  4131  and a second sleeved end  4132 . The first motor  414  is fixed on the first shaft  321  and rotates synchronously with the first shaft, and the first conveying belt  413  is sleeved on the first motor  414  via the first sleeved end  4131 . The second motor  415  is fixed at the first fixed end  4111  and rotates synchronously with the first transmission shaft  411 , and the first conveying belt  413  is sleeved on the second motor  415  via the second sleeved end  4132 . 
     Further, the m/2 first rotor sets correspond to the m/2 second transmission shafts  412  one by one, that is, one of the first rotor sets corresponds to one of the m/2 second transmission shafts  412 . The m/2 first rotor sets are correspondingly engaged with the m/2 fourth bevel gear ends  4122  of the m/2 second transmission shafts  412  via the bevel gear structures respectively, the m/2 second transmission shafts  412  are distributed symmetrically by taking the first transmission shaft  411  as a central vertical shaft, the m/2 third bevel gear ends  4121  of the m/2 second transmission shafts  412  are engaged with the first bevel gear end  4112  of the first transmission shaft  411  to convert the vertical rotation of the first transmission shaft  411  to the transverse rotation of the second transmission shafts  412 , and then each rotor  21  in the m/2 first rotor sets is driven to rotate by the transverse rotation of the second transmission shafts  412 . 
     The first belt transmission device  41  and the second belt transmission device  42  in the embodiment of the present invention are symmetrically distributed on two sides of the power device  3 , i.e., it could be understood that the first belt transmission device  41  is arranged on one side of the first shaft  321  and correspondingly carries out mechanical transmission with the first shaft  321 , and the second belt transmission device  42  is arranged on one side of the second shaft  331  and correspondingly carries out mechanical transmission with the second shaft  331 . 
     Similarly, the second belt transmission device  42  includes a third transmission shaft  421 , m/2 fourth transmission shafts  422 , a second conveying belt  423 , a third motor  424  and a fourth motor  425 . The third transmission shaft  421  includes a second fixed end  4211  and a fifth bevel gear end  4212 , and the fifth bevel gear end  4212  is of a bevel gear structure. Each fourth transmission shaft  422  includes a sixth bevel gear end  4221  and a seventh bevel gear end  4222 , and both the sixth bevel gear end  4221  and the seventh bevel gear end  4222  are of a bevel gear structure. The second conveying belt  423  includes a third sleeved end  4231  and a fourth sleeved end  4232 . The third motor  424  is fixed on the second shaft  331  and rotates synchronously with the second shaft  331 , and the second conveying belt  423  is sleeved on the third motor  424  via the third sleeved end  4231 . The fourth motor  425  is fixed at the second fixed end  4211  and rotates synchronously with the third transmission shaft  421 , and the second conveying belt  423  is sleeved on the fourth motor  425  via the fourth sleeved end  4232 . 
     Similarly, the m/2 second rotor sets correspond to the m/2 fourth transmission shafts  422  one by one, that is, one of the m/2 second rotor sets corresponds to one of the m/2 fourth transmission shafts  422 . The m/2 second rotor sets are correspondingly engaged with the m/2 seventh bevel gear ends  4222  of the m/2 fourth transmission shafts  422  via the bevel gear structures respectively, the m/2 fourth transmission shafts  422  are distributed symmetrically by taking the third transmission shaft  421  as a central vertical shaft, the m/2 sixth bevel gear ends  4221  of the m/2 fourth transmission shafts  422  are engaged with the m/2 fifth bevel gear ends  4212  of the third transmission shaft  421  to convert the vertical rotation of the third transmission shaft  421  to the transverse rotation of the fourth transmission shafts  422 , and then each rotor  21  in the m/2 second rotor sets is driven to rotate by the transverse rotation of the fourth transmission shafts  422 . 
     In the embodiment of the present invention, the quantity of rotors in each rotor set  2  may be n, and the n is an integer more than or equal to 2. 
     Certainly, in the embodiment of the present invention, in order to better describe the mechanical transmission between the rotor sets  2  and the first belt transmission device  41  and between the rotor sets  2  and the second belt transmission device  42  in detail, m=3 and n=4 are taken as an example for further elaboration. Certainly, those skilled in the art could obviously understand that m=4 is merely a way to assume value, n=3 is also merely a way to assume value, and when the m is equal to an even number such as 6, 8, 10 or the like and the n is equal to an integer value such as 2, 4, 5, 6 or the like, they are also applicable to the present invention. 
     For example, when m=4 and n=3, there are totally four rotor sets  2  including two first rotor sets and two second rotor sets, and each rotor set  2  includes three rotors  21 . At the moment, the two rotor sets (first sets) in the four rotor sets are distributed on one side of the first transmission shaft  411 , and the other two rotor sets (second sets) in the four rotor sets are distributed on one side of the second transmission shafts  412 . Meanwhile, the first belt transmission device  41  includes two second transmission shafts  412 . Each second transmission shaft  412  includes a third bevel gear end  4121  and a fourth bevel gear end  4122 , and both the third bevel gear end  4121  and the fourth bevel gear end  4122  are of a bevel gear structure. Thus, the two first rotor sets correspond to the two second transmission shafts  412 , that is, one of the first rotor sets corresponds to one of the two second transmission shafts  412 . The two first rotor sets are correspondingly engaged with the two fourth bevel gear ends  4122  of the two second transmission shafts  412  via the bevel gear structures respectively; and the two second transmission shafts  412  are distributed symmetrically by taking the first transmission shaft  411  as a central vertical shaft, the two third bevel gear ends  4121  of the two second transmission shafts  412  are engaged with the first bevel gear end  4112  of the first transmission shaft  411  to convert the vertical rotation of the first transmission shaft  411  to the transverse rotation of the second transmission shafts  412 , and then the three rotors  21  in each of the two first rotor sets  2  are driven to rotate by the transverse rotation of the second transmission shafts  412 . 
     Similarly, the second belt transmission device  42  also includes two fourth transmission shafts  422 , wherein each of the two fourth transmission shafts  422  includes a sixth bevel gear end  4221  and a seventh bevel gear end  4222 , and both the sixth bevel gear end  4221  and the seventh bevel gear end  4222  are of a bevel gear structure. Thus, the two second rotor sets correspond to the two fourth transmission shafts  422  one by one, that is, one of the two second rotor sets corresponds to one of the two fourth transmission shafts  422 . The two second rotor sets are correspondingly engaged with the two seventh bevel gear ends  4222  of the two fourth transmission shafts  422  via the bevel gear structures respectively; and the two fourth transmission shafts  422  are distributed symmetrically by taking the third transmission shaft  421  as a central vertical shaft, the two sixth bevel gear ends  4221  of the two fourth transmission shafts  422  are engaged with the two fifth bevel gear ends  4212  of the third transmission shaft  421  to convert the vertical rotation of the third transmission shaft  421  to the transverse rotation of the fourth transmission shafts  422 , and then the three rotors  21  in each of the two second rotor sets  2  are driven to rotate by the transverse rotation of the fourth transmission shafts  422 . 
     It is worth mentioning that in the embodiment of the present invention, the first rotor sets  2  are as many as the second transmission shafts  412 , and the second rotor sets  2  are as many as the fourth transmission shafts  422 , but the quantity of the first rotor sets  2  and the quantity of the second rotor sets  2  may be different. In other words, whether the quantity of the first rotor sets  2  and the quantity of the second rotor sets  2  are same is not limited by the embodiment of the present invention, and they are available as long as the first rotor sets  2  are as many as the second transmission shafts  412  and the second rotor sets  2  are as many as the fourth transmission shafts  422 . Similarly, the first transmission shaft  411  is as many as the first shaft  321 , and the third transmission shaft  421  is as many as the second shaft  331 . However, the quantity of the first shaft  321  and the quantity of the second shaft  331  may be different, and their specific quantities are not limited in the present invention. In other words, according to the actual operating requirements, it is applicable to the present invention to design two, three, four or more first shafts  321 , two, three, four or more second shafts  331 , three, four or more first rotor sets  2  and three, four or more second rotor sets  2 , and as long as the corresponding quantity relations correspond to the above descriptions, these designs fall into the protection scope of the present invention. 
     In the embodiment of the present invention, with regard to the transmission between the rotor sets  2  and the second transmission shafts  412  or the fourth transmission shafts  422 , variable pitch devices  6  may be adopted for connecting, as shown in  FIG. 3 . It should be noted that the transmission between each rotor set  2  and each second transmission shaft  412  or fourth transmission shaft  422  is realized by one variable pitch device  6 , so for simplifying the description, only one variable pitch device  6  is elaborated in the embodiment of the present invention. For the transmission between the remaining rotor sets  2  and the corresponding second transmission shafts  412  or fourth transmission shafts  422 , reference may be directly made to the variable pitch device  6 . Continuously referring to  FIGS. 11-12 , the variable pitch device  6  at least includes a main shaft  61 , an up-down slider  62 , an anti-lock mechanism  63 , an actuator  64  and a force transfer arm  65 . The n rotors  21  are rotatably fixed on the main shaft  61 , the up-down slider  62  is sleeved on the main shaft  61 , the actuator  64  is movably connected with the anti-lock mechanism  63 , the anti-lock mechanism  63  is movably connected with the up-down slider  62 , and the actuator  64  drives the up-down slider  62  to slide up and down. The force transfer arm  65  is connected with the up-down slider  62  and the rotors  21  respectively, so that the up-down slider  62  drives the rotors  21  to rotate in the up-down sliding process to change the pitches of the rotors  21 . The anti-lock mechanism  63  includes a first rocker arm  631 , a second rocker arm  632  and a positioning block  633 . 
     Specifically, the up-down slider  62  is of a hollow structure (cylindrical hollow structure), and is sleeved on the outer wall of the main shaft  61  via the hollow structure; one end of the first rocker arm  631  is movably connected with the up-down slider  62 ; the other end of the first rocker arm  631  is movably connected with one end of the second rocker arm  632 ; the other end of the second rocker arm  632  is movably connected with the positioning block  633 ; and the positioning block  633  is fixed at the end of the second transmission shaft or the fourth transmission shaft. In practical operation, one end of the first rocker arm  631  is movably connected with the up-down slider  62 , so that the first rocker arm  631  can rotate by taking the connection part of the first rocker arm  631  and the up-down slider  62  as a center point; the other end of the first rocker arm  631  is movably connected with one end of the second rocker arm  632 , so that the first rocker arm  631  and the second rocker arm  632  can rotate by taking respective connection parts as center points; the other end of the second rocker arm  632  is movably connected with the positioning block  633 , so that the second rocker arm  632  can rotate by taking the connection part of the second rocker arm  632  and the positioning block  633  as a center point; the top of an actuator connecting arm  641  is movably connected with the side of the first rocker arm  631 ; the bottom of the actuator connecting arm  641  is connected with the actuator  64 ; that is, the actuator  64  can transfer actuator thrust to the first rocker arm  631  via the actuator connecting arm  641 , and then drives the first rocker arm  631  to swing. 
     In the embodiment of the present invention, in order to facilitate movable connection among the first rocker arm  631 , the second rocker arm  632  and the up-down slider  62  and realize relative rotation between every two, a first U-shaped part  6312  is preferably formed at one end of the first rocker arm  631 ; the first rocker arm  631  is sleeved outside the up-down slider  62  via the U-shaped notch of the first U-shaped part  6312 , and movably connected with the up-down slider  62  via the first U-shaped part  6312 ; a first raised part  6311  is formed at the other end of the first rocker arm  631 ; a first connecting hole is formed in the end of the first raised part  6311 ; the first raised part  6311  is movably connected with one end of the second rocker arm  632  via the first connecting hole; a second U-shaped part  6321  adapting to the first raised part  6311  in shape is formed at one end of the second rocker arm  632 ; the first raised part  6311  is placed inside the U-shaped notch of the second U-shaped part  6321  and movably connected with one end of the second rocker arm  632  via the second U-shaped part  6321 . A third U-shaped part  6322  is formed at the other end of the second rocker arm  632 ; a second raised part  6311   a  adapting to the U-shaped notch of the third U-shaped part in structure is formed at one end of the positioning block  633 ; a second connecting hole is formed in the end of the second raised part  6311   a ; and the second raised part  6311   a  is placed inside the U-shaped notch of the third U-shaped part  6322  and movably connected with the third U-shaped part  6322  at the other end of the second rocker arm via the second connecting hole. The actuator connecting arm  641  is of a crescent structure; at least one third connecting hole is formed in the top of the actuator connecting arm  641 ; the top of the actuator connecting arm  641  is movably connected with the side wall of the first rocker arm  631  via the third connecting hole; a fourth U-shaped part  651  is formed at the bottom of the actuator connecting arm  641 ; and the bottom of the actuator connecting arm  641  is connected with the actuator  64  via the fourth U-shaped part  651 . 
     In the embodiment of the present invention, the wing profile attack angles of the rotors  21  are changed via the variable pitch devices  6 , so that the wing profile lift force is changed to adjust the output power, the rotating speed of the rotors is maintained unchangeable, and vertical motion, roll motion and steering motion are realized by changing the pitches of the rotors  21 . Meanwhile, the folding mechanical motion mode among the up-down slider  62 , the first rocker arm  631  and the actuator connecting arm  641  and the folding mechanical motion mode among the up-down slider  62 , the first rocker arm  631  and the second rocker arm  632  overcome the situation that the rotors  21  are locked because the main shaft  61  cannot completely fall in the ascending and descending process in the presence of a too long actuator connecting arm  641  due to the limitation of the mechanical structure (straight bar shape) of an actuator connecting rod on positional space in the prior art, and simultaneously overcome the defect that the main shaft cannot ascend to an operating point in the ascending process in the presence of a too short actuator connecting arm  641 . 
     Obviously, various alterations and modifications can be made to the present invention by those skilled in the art without departing from the spirit and scope of the present invention. In case that these alterations and modifications of the present invention fall into the scope of the claims of the present invention and equivalent technologies thereof, the present invention is also intended to include these alterations and modifications.