Composite propeller

Abstract

The utility model provides a composite propeller, and belongs to the field of power propulsion. The composite propeller comprises a main propeller, a plurality of auxiliary propellers and a revolute pair. The auxiliary propellers are distributed around the main propeller, the auxiliary propellers are connected with the main propeller through revolute pairs, the main propeller can drive the auxiliary propellers to revolve when rotating around the main propeller, and the auxiliary propellers can rotate while revolving to jointly provide propelling force of the composite propeller. The concept of the composite propeller provided by the utility model provides a new choice for the design of the propeller.

Description

Technical Field

[0001] The utility model belongs to the field of power propulsion, and in particular relates to a composite propeller. Background Art

[0002] A propeller is a device that converts rotational power into propulsion by rotating the blades in a fluid. Propeller technology is becoming more and more mature and is widely used in the fields of aviation, shipping and energy. In recent years, the UAV industry has developed rapidly, and UAVs are increasingly used in civil and military fields, playing an increasingly important role. As one of the hot spots in UAV design, multi-rotor aircraft has the characteristics of simple structure and good maneuverability. It has a broad market prospect and has developed particularly rapidly in recent years. Propellers are the most important source of propulsion for UAVs. The market has increasingly higher requirements for the efficiency and performance of propellers. Traditional propeller technology has reached a bottleneck, and a new propulsion technology is urgently needed.

[0003] The rotor of a helicopter can be regarded as a special type of propeller, which can provide directional control in addition to lift. The helicopter rotor rotates continuously, and the air flows over the upper surface of the blade, the flow tube becomes thinner, the flow rate increases, and the pressure decreases; when the air flows over the lower surface of the blade, the flow tube becomes thicker, the flow rate slows down, and the pressure increases. In this way, a pressure difference is formed between the upper and lower surfaces of the blade, and an upward pulling force is generated on the blade. By controlling the inclination of the rotor cone in the forward, backward, left and right directions, forces in different directions can be obtained. However, the rotor mechanism design of existing helicopters is too complicated, and there are a series of problems such as heavy structural weight, low reliability, and high noise. Designing a propeller with vector control capability is very beneficial to improving the performance of the aircraft.

[0004] During the rotation process, the propeller acts against the fluid to change the flow, so that the flow field forms a pressure difference on the upper and lower surfaces of the propeller, thereby generating propulsion. In this process, the blades are affected by the fluid resistance, which will form a torque in the opposite direction of rotation on the propeller, that is, the anti-torque. This anti-torque will eventually be transmitted to the fuselage and needs to be offset by other external forces. The propellers of multi-rotor drones need to rotate in different directions to offset the torque. The helicopter is equipped with a small vertically rotating rotor at the tail, called the tail rotor, which applies a horizontal force to balance the anti-torque of the rotor. In addition, there are some coaxial twin-propeller designs, but these designs either make the mechanism more complicated or require the addition of more power devices, resulting in an increase in weight and cost. Designing a thrust device without anti-torque can solve a major difficulty in aircraft design. Utility Model Content

[0005] In order to solve at least one of the above problems, the utility model provides a composite propeller, including a main propeller, a plurality of auxiliary propellers and a rotating pair.

[0006] The auxiliary propellers are distributed around the main propeller, and the auxiliary propellers are connected to the main propeller via a rotating pair.

[0007] The number of the secondary propellers is not limited, and preferably, the number of the secondary propellers can be three.

[0008] The utility model provides a composite propeller, which is characterized in that the auxiliary propeller rotates along with the main propeller, that is, the auxiliary propeller revolves around the center of the main propeller.

[0009] The auxiliary propeller can generate propulsion force when interacting with the fluid during its rotation.

[0010] When the secondary propeller is in orbit, the incoming flow in the forward direction of the secondary propeller acts on the secondary propeller, which can generate a gain in the propulsion force of the secondary propeller.

[0011] The incoming flow in the forward direction of the auxiliary propeller refers to the movement of the auxiliary propeller relative to the air, and does not specifically refer to a certain direction as the forward direction.

[0012] The various propulsion forces generated by the auxiliary propeller are transmitted to the main propeller through the rotating pair.

[0013] When the main propeller rotates, it interacts with the fluid, causing the flow field to form a pressure difference between the upper and lower surfaces of the propeller, thereby generating propulsion.

[0014] The propulsion force generated by the rotation of the main propeller and the propulsion force generated by the auxiliary propeller together constitute the propulsion force of the composite propeller.

[0015] During the rotation of the auxiliary propeller, the blades are affected by the fluid resistance, which will form a torque opposite to the rotation direction. The torque is transmitted to the main propeller through the rotating pair, causing the main propeller to rotate in the opposite direction.

[0016] The resultant torque of the counter-torques generated by all the auxiliary propellers is equal in magnitude to the counter-torque generated by the main propeller, but opposite in direction, and can cancel each other out.

[0017] The utility model provides a composite propeller, characterized in that the main propeller and the auxiliary propeller rotate in opposite directions. Various torques generated by the composite propeller in the rotation direction can offset each other and will not be transmitted to external connecting objects.

[0018] It should be noted that the above-mentioned feature means that the composite propeller has the advantage of not generating external reverse torque compared to ordinary propellers. However, in certain circumstances, such as when the composite propeller is still in speed regulation and has not reached a stable state, or when other torques in the direction of rotation are required to be provided by the composite propeller, the torques generated by the main propeller and the auxiliary propeller may not be completely offset.

[0019] Furthermore, different auxiliary propellers can generate different thrusts by controlling the rotation speeds of different auxiliary propellers respectively, so that their combined force does not pass through the center of the compound propeller, thereby providing a tilt torque perpendicular to the direction of rotation, so that the compound propeller has the ability of vector control.

[0020] It should be noted that the propulsion force described in the present invention refers to the force generated by the propeller parallel to the direction of rotation, which may be expressed as lift, thrust, pull or similar expressions in different scenarios.

[0021] It should be noted that the torque and counter-torque described in the present invention refer to the moment in the propeller's rotation direction, including driving torque and fluid counter-torque, etc. In the absence of special instructions, torque is often expressed as moment.

[0022] The fluid counter-torque on the main propeller refers to the counter-torque in the rotation direction formed by combining the horizontal resistance directly on the main propeller itself and the horizontal resistance transmitted by other parts.

[0023] It should be noted that the tilting moment described in the present invention refers to a moment perpendicular to the rotation direction.

[0024] It should be noted that the positive and negative mentioned in the present invention are to distinguish two opposite directions. Generally, combined with the context, it can be judged that the first mentioned or more normal one is positive, and the opposite one is negative, rather than the positive and negative of a certain coordinate system or a specific direction.

[0025] Generally, as a propeller, under different motion states, it will be subjected to various forces and moments like ordinary propellers, such as gravity, etc., which will not be elaborated here.

[0026] The utility model provides a composite propeller, wherein all or part of the rotating pairs can be powered rotating pairs.

[0027] The powered rotating pair means that the rotating pair can not only constrain the relative rotation between the main propeller and the auxiliary propeller, but also provide power to drive the relative rotation.

[0028] The power rotating pair can be a device that can provide power, such as an electric motor or a combustion engine.

[0029] The utility model provides a composite propeller, which is characterized in that the powered rotating pair provides two torques in opposite directions, which act on the main propeller and the auxiliary propeller respectively, so that the main propeller and the auxiliary propeller rotate relative to each other.

[0030] The driving torque acts on the secondary propeller, driving the secondary propeller to rotate, thereby interacting with the fluid.

[0031] The fluid counter-torque applied to the auxiliary propeller increases with the increase of the rotation speed. When the magnitude of the fluid counter-torque is equal to the magnitude of the driving torque but the direction is opposite, the auxiliary propeller reaches stability in the rotation direction and maintains a stable rotation speed.

[0032] By increasing or decreasing the driving torque, the rotation speed of each auxiliary propeller can be regulated.

[0033] The driving counter torque drives the main propeller to rotate in the opposite direction, thereby interacting with the fluid. At the same time, the auxiliary propeller is driven by the main propeller to generate revolution.

[0034] The fluid counter-torque applied to the main propeller increases with the increase of the rotation speed. When the magnitude of the fluid counter-torque is equal to the sum of all driving counter-torques but the direction is opposite, the main propeller reaches stability in the rotation direction and maintains a stable rotation speed.

[0035] Similarly, when the driving torque becomes smaller, the opposite change will occur until a new balance is reached.

[0036] The utility model provides a composite propeller, which is characterized in that the propulsion force of the composite propeller is controlled by controlling the rotation speed of the powered rotating pair. When the propulsion force needs to be increased, the rotation speed of each rotating pair is increased at the same time; when the propulsion force needs to be reduced, the rotation speed of each rotating pair is reduced at the same time.

[0037] The rotation speeds of the different auxiliary propellers are not completely the same, and the rotation directions may also be different. By controlling the different auxiliary propellers to produce different rotation speeds, a tilting moment perpendicular to the rotation direction can be generated.

[0038] In particular, by controlling the powered rotating pair in a specific direction to increase or decrease the speed, and controlling the powered rotating pair in the opposite direction to decrease the speed, the auxiliary propellers in different directions can have different speeds, thereby generating a tilting torque perpendicular to the direction of rotation, thereby achieving the effect of vector control.

[0039] It should be noted that the increase in speed has a direction, that is, if the auxiliary propeller is rotating forward, then increasing the speed (such as increasing from 5 to 10) means increasing the absolute value of the speed, but if the auxiliary propeller is rotating backward, then increasing the speed (such as increasing from -10 to -5) will actually reduce its absolute value. Similarly, the change from reverse rotation to forward rotation (such as increasing from -5 to 5) is also called an increase. Similarly, the reduction in speed also has a direction.

[0040] The utility model provides a composite propeller, which is characterized in that by periodically adjusting the rotation speed of each auxiliary propeller so that the rotation speed of each auxiliary propeller increases when reaching a specific direction and decreases when reaching the opposite direction, a tilting torque can be formed as a whole.

[0041] In particular, when some of the rotating pairs are unpowered rotating pairs, or some of the powered rotating pairs do not provide power due to failure or other reasons, the auxiliary propeller corresponding to the rotating pair is not directly controlled by the rotating pair, but will revolve under the drive of the main propeller, and at the same time interact with the fluid, and then passively rotate.

[0042] M represents the moment, Q represents the horizontal resistance, L represents the pulling force, D represents the resistance, β represents the secondary propeller angle of attack, r represents the position of the blade element point, C represents the horizontal resistance, L represents the auxiliary propeller lift coefficient, C D represents the secondary propeller drag coefficient, β 2 represents the main propeller angle of attack, C L2 represents the main propeller lift coefficient, C D 2 represents the main propeller drag coefficient, Ω represents the auxiliary propeller angular velocity, V represents the revolution linear velocity, θ represents the relative angle between the auxiliary propeller and the main propeller, r 0 represents the radius of the auxiliary propeller, R represents the radius of the main propeller, c represents the chord length of the auxiliary propeller, v 0 is the rising speed, v 1 is the axial induced speed of the secondary propeller, v 2 is the circumferential induced velocity of the secondary propeller, v 3 is the circumferential induced velocity of the main propeller, ρ represents the fluid density, n is the number of blades of the auxiliary propeller, and N is the number of blades of the main propeller. The expression of the auxiliary propeller torque obtained is related to θ. Since the relative angle between the main propeller and the auxiliary propeller changes in real time, the torque is also constantly changing. Here, the integral averaging method is adopted. Since the overall force and torque of the composite propeller are balanced, the torque generated by the rotation of the main propeller and the torque generated by the auxiliary propeller can offset each other.

[0043] Reference Figure 6 Flow direction and force analysis and Figure 8 The relative position of the main propeller and the auxiliary propeller, the auxiliary propeller flow velocity can be expressed as

[0044]

[0045] The above formula can also be used to derive the small propeller angle β

[0046]

[0047] The pull and resistance of the auxiliary propeller can be expressed as the following formula. It should be noted that the pull direction is perpendicular to the blade direction, and the resistance direction is opposite to the blade direction, not completely vertical.

[0048]

[0049]

[0050]

[0051]

[0052] The pull and resistance of a single blade can be obtained by integration. The pull or resistance of multiple blades of the main propeller and the auxiliary propeller are accumulated to obtain the pull and resistance of the main propeller and the auxiliary propeller respectively.

[0053] The final propulsion force is

[0054] T=Lcosβ-Dsinβ

[0055] The above formula can be applied to the main propeller blades and auxiliary propeller blades to obtain the main propeller blade propulsion force T 主桨桨叶 and the auxiliary propeller blade thrust T 副桨桨叶

[0056] The horizontal resistance of the auxiliary propeller blade is a combination of the horizontal component of the pulling force and the horizontal component of the resistance. The torque it is subjected to is obtained by integrating the horizontal resistance over the lever arm, and the following expression is obtained after simplification.

[0057]

[0058] The auxiliary propeller blade torque is related to the relative position of the auxiliary propeller and the main propeller. For the convenience of calculation, the integration and averaging method is adopted here.

[0059]

[0060] The main propeller torque is expressed as follows.

[0061]

[0062] The main propeller and auxiliary propeller moments can cancel each other out.

[0063] M 主桨 =NM 副桨

[0064] The propulsive force on the composite propeller as a whole is as follows.

[0065] T 总 =NT 副桨 +T 主桨 =NnT 副桨桨叶 +T 主桨

[0066] The beneficial effects of the utility model are as follows:

[0067] 1. The utility model proposes a new concept of composite propeller, which provides a new choice for the design of propeller.

[0068] 2. The composite propeller provided by the utility model can offset the reverse torque by itself, providing a new solution to the torque problem of the aircraft, and helping to improve the performance of the aircraft.

[0069] 3. The composite propeller provided by the utility model has vector control capability, which helps to improve the performance of aircraft, marine vehicles, etc.

[0070] 4. The composite rotation scheme proposed in the utility model improves the aerodynamic efficiency of the propeller and reduces energy consumption. BRIEF DESCRIPTION OF THE DRAWINGS

[0071] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings in the following description are only embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0072] Figure 1 The effect diagram of the composite propeller in a specific embodiment of the utility model

[0073] Figure 2 The auxiliary propeller and the rotating auxiliary propeller in a specific embodiment of the utility model are provided.

[0074] Figure 3 A main propeller in a specific embodiment provided by the utility model

[0075] Figure 4 The main propeller size in a specific embodiment of the utility model is

[0076] Figure 5 The dimensions of the composite propeller in a specific embodiment of the utility model are as follows:

[0077] Figure 6 A cross-sectional force diagram of a composite propeller blade in a specific embodiment of the utility model

[0078] Figure 7 A schematic diagram of the lateral flow in a specific embodiment of the utility model

[0079] Figure 8 Definition of the auxiliary propeller coordinate system in a specific embodiment provided by the utility model

[0080] Fig. 9 Counterclockwise deflection for composite propeller

[0081] Fig.10 Clockwise deflection for composite propeller

[0082] In the figure, 01 is the main propeller, 02 is the auxiliary propeller, 03 is the rotary pair, and 04 is the installation position. DETAILED DESCRIPTION

[0083] In order to make the technical problems, technical solutions and beneficial effects to be solved by the utility model clearer, the utility model is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the utility model and are not used to limit the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the utility model.

[0084] It should be noted that the specific dimensions, including length, height, distance, angle, etc., the specific quantity and the specific material appearing below are a feasible method provided to facilitate specific implementation, and they can be adjusted according to actual needs.

[0085] It should be understood that the structural design described in the present invention is to serve the function. Different structural designs can be used according to different usage scenarios while satisfying the basic functions. A structurally feasible method proposed below is for the convenience of those skilled in the art. According to the introduction of the present invention, the required verification composite propeller structure can be manufactured without creative work. It should be noted that similar numbers and letters represent similar items in the following figures, so once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0086] The materials, dimensions and methods of application of the present invention need to be determined according to the actual design, and only one specific embodiment is given here for illustration.

[0087] See also Figure 1 The utility model provides a composite propeller, comprising a main propeller 01, three auxiliary propellers 02, three rotating pairs 03, and a mounting position 04.

[0088] The mounting position is located in the middle of the main propeller and is used to mount the composite propeller on the fuselage.

[0089] The auxiliary propellers are evenly distributed around the main propeller at an angle of 120 degrees to each other. The auxiliary propellers are connected to the main propeller via a rotating pair, and the auxiliary propellers can rotate relative to the main propeller.

[0090] When the main propeller rotates around the mounting position, it drives the auxiliary propeller to revolve, and the auxiliary propeller can rotate while revolving.

[0091] The secondary propellers have the same rotation direction, and the rotation direction of the secondary propellers is opposite to that of the main propellers.

[0092] In some embodiments, the number of motors may be different from the number of secondary propellers.

[0093] In some embodiments, when the number of secondary propellers is another number, ie, not three, preferably, the degree between each secondary propeller is 360° divided by the number of secondary propellers.

[0094] In this embodiment, the composite propeller has a symmetrical structure, the geometric center coincides with the center of gravity of the propeller, and the three auxiliary propellers are completely equivalent. Given the same power of the three motors acting as rotating pairs, the resultant force of the lift of the three auxiliary propellers is on the same straight line as the geometric center of the composite propeller, so that the propeller as a whole maintains a stable posture without shaking.

[0095] In some embodiments, the distribution of the secondary propellers may also use other degrees of uneven distribution.

[0096] The mounting position is a hole, and the propeller is fixed to the body by bolts.

[0097] See also Figure 2 In this embodiment, the rotating pair can use an ordinary model aircraft motor, and the term "motor" will be used uniformly below.

[0098] In this embodiment, the auxiliary propeller may use a common model aircraft propeller.

[0099] See also Figure 3 The main propeller can be made by 3D printing or mold injection molding, and the specific shape can be optimized according to different usage scenarios.

[0100] See also Figure 4 and Figure 5 The specific dimensions of the composite propeller are: the diameter of the auxiliary propeller is 11.81cm, the chord length of the auxiliary propeller is 1.18cm, the radius of the main propeller is 15.7cm, the chord length of the main propeller is 3.60cm, the angle of attack of the main propeller is about 15 degrees, and the auxiliary radius of rotation is 1.22cm.

[0101] Here, the main force transmission of the composite propeller is located on the main propeller blades between the rotating pair and the main propeller axis. The lift generated by the high-speed rotation of the auxiliary propeller driven by the rotating pair is transmitted to the main propeller blades through the rotating pair, and then transmitted to the main propeller axis in the form of shear flow; the force and torque generated by the relative action of the main propeller and the fluid also act on the main propeller blades in the form of shear force from different directions, and finally transmitted to the installation position in the center of the main propeller, thereby providing propulsion for the body.

[0102] When the auxiliary propeller blades rotate at high speed, the counter-torque caused by resistance acts on the blade frame in the form of torque and tensile pressure through the revolving pair, and is balanced by the torque synthesized by the fluid resistance on the main propeller, and is basically not transmitted to the fuselage.

[0103] The theoretical model of the composite propeller is partially as follows.

[0104] The lift of the compound propeller is provided by three auxiliary propellers and the main propeller.

[0105] T 总 =3×[T 副桨 (θ,Ω,ω)+T 副桨 (θ+π,Ω,ω)]×k+T 主桨

[0106] The power required for the rotor is

[0107] P=6ΩQk

[0108] The lift, drag and pull are as follows, and can all be expressed as functions related to θ.

[0109]

[0110]

[0111]

[0112] Integrating the blade torque microelement yields

[0113]

[0114]

[0115] The drag, lift, horizontal resistance, and torque of the large propeller are similar.

[0116]

[0117]

[0118]

[0119] The final composite propeller overall torque is 0, refer to Figure 7 .

[0120] M 主桨 +3M 副桨 =0

[0121] In a specific embodiment of the present invention, the driving method of the composite propeller is as follows:

[0122] The auxiliary propeller is driven by the motor to rotate, thereby interacting with the fluid. The dynamic reaction torque drives the main propeller to rotate in the opposite direction. At the same time, the auxiliary propeller is driven by the main propeller to produce revolution.

[0123] When the propulsion force needs to be increased, the speed of all motors is increased at the same time; when the propulsion force needs to be reduced, the speed of all motors is reduced at the same time.

[0124] The utility model provides a driving method for a composite propeller, which also has a vector control function.

[0125] The utility model provides a driving method for a composite propeller, which relies on the periodic speed change of each rotating pair, that is, when a rotating pair approaches the desired direction of movement, its rotation speed is reduced, and the rotation speed reaches the lowest when it reaches the position of the desired direction of movement; when a rotating pair is away from the desired direction, its rotation speed is increased, and the rotation speed reaches the highest when it reaches the position in the opposite direction of the desired movement. For the composite propeller, the thrust in the desired opposite direction will always be greater than the thrust in the desired direction, so a tilt torque toward the desired direction will be formed as a whole, thereby realizing vector control.

[0126] See also Figure 7 When the pulling force of the auxiliary propeller in front of the y-axis (Ox-axis direction) is increased and the pulling force of the auxiliary propeller behind the y-axis is reduced, a positive rotation torque rotating around the y-axis will be generated on the xOz plane, which will increase the tilt angle of the composite propeller as a whole from zero, and the lifting direction will point to the positive direction of the Ox-axis. Since the overall resultant force will generate a component force in the negative direction of the Ox-axis, it will cause the whole to move backward.

[0127] See also Figure 8 When the pulling force of the auxiliary propeller behind the y-axis (negative direction of the Ox-axis) is increased and the pulling force of the auxiliary propeller in front of the y-axis is reduced, a reverse rotation torque rotating around the y-axis will be generated on the xOz plane, which will reduce the tilt angle of the composite propeller as a whole to zero and then increase, and the lifting direction will become the negative direction of the x-axis. Since the overall resultant force will generate a component force in the positive direction of the x-axis, it will brake the whole body backward and move forward.

[0128] Furthermore, for any symmetry axis in the plane where the composite propeller is located, increasing the power of the rotating pair on one side and reducing the power of the rotating pair on the other side will cause the composite propeller as a whole to tilt in the direction of less thrust. The overall resultant force will generate a component force in the direction of reducing the thrust of the rotating pair, and the component force causes the entire composite propeller to move in that direction.

[0129] It should be noted that the motor speed and the thrust of the compound propeller are not one-to-one corresponding, so feedback adjustment is required during control. Any required thrust can be corresponded to the basic speed of the motor, but the thrust of the compound propeller may be too large or too small due to actual conditions. At this time, it is necessary to judge through sensors or changes in the posture of the body. If the thrust is insufficient, the reference speed needs to be increased, and if the thrust is too large, the reference speed needs to be reduced. The feedback can use the PID algorithm.

[0130] On this basis, according to the needs of vector control, the direction and size of the required tilting torque are judged, the required thrust change is determined, and the maximum and minimum speeds in the cycle are determined. Then, when each auxiliary propeller orbits to a different position, a corresponding speed change is given according to the position, and the speed of the auxiliary propeller corresponding motor is obtained after adding the reference speed for output.

[0131] The utility model provides a driving method for a composite propeller, and the specific steps include:

[0132] 1. According to the thrust requirement, determine the speed of the auxiliary propeller according to the corresponding relationship;

[0133] 2. According to the sensor data, determine whether the thrust is too large or too small, and adjust the speed through negative feedback to make the thrust meet the requirements;

[0134] 3. According to the vector control requirements, determine the size and direction of the tilt torque, calculate the thrust change based on the size, and calculate the thrust and speed change required for the auxiliary propellers in different positions;

[0135] 4. Determine the required change in rotation speed based on the position of each auxiliary propeller at each moment;

[0136] 5. Each auxiliary propeller outputs the speed change after adding the reference speed.

[0137] The above description of the disclosed embodiments enables professionals and technicians in this field to implement or use the utility model. Obviously, the above embodiments of the utility model are only examples for clearly illustrating the utility model, and are not limitations on the implementation methods of the utility model. For ordinary technicians in the relevant field, other different forms of changes or modifications can be made on the basis of the above description. It is impossible to list all the implementation methods here. Any modification, equivalent replacement, improvement and other changes or changes made to the technical solution of the utility model within the spirit, principle and inventive concept of the utility model, the equivalent structure or control transformation made by the description and drawings of the utility model, or direct / indirect application in other related technical fields, should be included in the protection scope of the utility model. Therefore, the utility model will not be limited to the embodiments shown in this article, but will comply with the widest range consistent with the principles and novel features disclosed herein.

Claims

1. A composite propeller, comprising a main propeller, a plurality of auxiliary propellers and a rotating pair, characterized in that: The auxiliary propellers are distributed around the main propeller, and the auxiliary propellers are connected to the main propeller via the rotating pair. When the main propeller rotates around itself, it drives the auxiliary propellers to revolve, and the auxiliary propellers rotate while revolving.

2. A composite propeller according to claim 1, characterized in that: The propulsion of the compound propeller is generated by the main propeller and the auxiliary propeller.

3. A composite propeller according to claim 1, characterized in that: The number of the secondary propellers is three.

4. A composite propeller according to claim 1, characterized in that: The secondary propeller revolves while rotating, and uses the forward flow generated by the revolution to generate lift gain.

5. A composite propeller according to claim 1, characterized in that: The counter-torque generated by the rotation of the secondary propeller acts directly or indirectly on the main propeller through the revolving pair, thereby driving the rotation of the main propeller.

6. A composite propeller according to claim 1, characterized in that: The torques generated inside the composite propeller cancel each other out and will not be transmitted to external connections.

7. A composite propeller according to claim 1, characterized in that: There are multiple auxiliary propellers, and the rotational speeds of different auxiliary propellers are not exactly the same, thereby generating a tilting torque and having the ability of vector control.

8. The composite propeller according to claim 1, characterized in that: All or part of the revolving pairs are powered revolving pairs.

9. A composite propeller according to claim 8, characterized in that: The powered rotating pair drives the main propeller and the auxiliary propeller to rotate simultaneously.

10. The composite propeller according to claim 1, characterized in that: The rotating pair part is an unpowered rotating pair, which is driven by the main propeller to revolve and then rotate.

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