A rotor based on a flexible blade

Abstract

The present invention discloses a rotor based on flexible blades. A plurality of blades are evenly spaced on a rotor shaft. The blades are made of flexible materials, and high-strength tensile ropes are arranged therein. The blades reduce the interference of lift changes in the advancing area and the retreating area of the blades during forward flight and gust interference through deformation; a winglet mechanism is inserted and fixed at the wingtip of the blade, and a winglet is installed on the winglet mechanism. The winglet is arranged parallel to the blade; the winglet has an angle of attack relative to the blade chord line, which is used to provide a torsional moment for the blade to have an angle of attack. By adopting the above rotor, the unmanned aerial vehicle is less affected by the wind, flies more stably, has clear imaging during shooting, and is also more convenient for shipboard operation and storage.

Description

Technical Field

[0001] The present invention relates to the technical field of multi-rotors, and in particular to a rotor based on flexible blades. Background Art

[0002] A multi-rotor is an aircraft capable of vertical takeoff and landing, and has broad application prospects in military and civilian fields. Stability is one of the key indicators for measuring the flight performance of rotor unmanned aerial vehicles.

[0003] Currently, all the rotors of multi-rotor unmanned aerial vehicles are rigid blades. When flying forward, there is a speed difference in the airflow between the advancing area and the retreating area of the blade, resulting in different lift forces during one rotation of the blade. In the state of high-speed rotation, it will inevitably lead to the vibration of the whole unmanned aerial vehicle. Gusts of wind will also cause the unmanned aerial vehicle to vibrate or even become unstable. In scenarios with high requirements for flight attitude stability, the vibration of the whole aircraft will cause the unmanned aerial vehicle to malfunction. For example, for unmanned aerial vehicles used in fields such as aerial photography and firefighting, vibration is likely to cause unclear imaging. During the forward flight of the aircraft, the vibration of the rigid rotor caused by the wind force is likely to cause fatigue damage to the blade, and even cause the multi-rotor to become unstable and damaged. When the rigid rotor encounters obstacles such as tree branches during flight, the buffer is small and the blade is easily damaged. The rigid rotor occupies a large space and is not convenient for shipborne use, storage, and transportation. Summary of the Invention

[0004] To overcome the above deficiencies, the present invention proposes a rotor based on flexible blades. The blades can reduce the vibration of the whole unmanned aerial vehicle caused by the advancing area and the retreating area of the forward flight blades and gusts of wind through deformation, and improve flight stability.

[0005] To achieve the above object, the present invention proposes the following technical solutions:

[0006] A rotor based on flexible blades, wherein a plurality of blades are arranged on a rotor shaft. The blades are made of flexible materials, and high-strength tensile ropes are arranged therein. The blades reduce the interference of lift force changes caused by the advancing area and the retreating area and gust interference through deformation; a winglet mechanism is fixed at the wing tip of the blade, and a winglet is installed on the winglet mechanism. The winglet is arranged parallel to the blade; the winglet has an angle of attack relative to the chord line of the blade, and when the winglet rotates with an angle of attack, it is used to provide a torsional moment for the blade so that the blade has an angle of attack when rotating.

[0007] Preferably, the number of the winglets is two, and the winglets are symmetrically installed on both sides of the blade.

[0008] Preferably, a balance weight is further arranged on the winglet mechanism, and the balance weight and the winglet are installed on both sides of the blade.

[0009] The present invention adopts the above-mentioned rotor. The flexible blades reduce the interference of lift changes caused by the advancing area and the retreating area and the flight interference of gusts to the aircraft through deformation. Moreover, the rotor composed of flexible blades can bend up and down in the rotation plane, reducing the rotor diameter in the static state of the rotor, which is beneficial for shipborne use and storage and transportation. Description of the Drawings

[0010] Figure 1 It is a schematic structural diagram of the unmanned aerial vehicle rotor according to an embodiment of the present invention;

[0011] Figure 2 It is a first schematic structural diagram of the winglet mechanism in an embodiment of the present invention;

[0012] Figure 3 It is a second schematic structural diagram of the winglet mechanism in an embodiment of the present invention;

[0013] Figure 4 It is a schematic diagram of the curve groove in another embodiment of the present invention.

[0014] Reference Signs

[0015] 1, winglet mechanism; 2, blade; 3, rotor shaft; 4, winglet; 5, winglet frame; 6, balance weight; 7, curve groove. Detailed Embodiments

[0016] The technical solutions of the present invention will be further described below in conjunction with the drawings and embodiments.

[0017] As Figure 1 shown, for the rotor based on flexible blades, two flexible blades 2 are arranged on the rotor shaft 3. The blades 2 reduce the interference of lift changes and gusts through deformation. The material of the blades 2 is a flexible material such as rubber, polyurethane, polyvinyl chloride, or silicone. High-strength tensile ropes are arranged inside the blades 2 and fixed to the blade base material to bear the centrifugal force of the blades 2. The material of the ropes can be nylon, high-molecular polyethylene fiber ropes, steel wires, etc. Winglet mechanisms 1 are fixed at the wingtips of the blades 2.

[0018] As Figure 2 shown, the winglet frames 5 are fixed to the blades 2. Two winglets 4 are installed on the winglet mechanisms 1. The winglets 4 are arranged parallel to the blades 2 and symmetrically installed on the winglet frames 5 on both sides of the blades 2. The winglets 4 have an angle of attack relative to the chord line of the blades 2. This angle of attack can provide a torsional moment during the rotation of the rotor to make the flexible blades 2 have an angle of attack. The angle of attack of the blades 2 is positively correlated with the torsional moment provided by the winglets 4.

[0019] As Figure 3As shown, on the winglet mechanism 1, one of the winglets 4 can also be replaced by a balance weight 6. The balance weight 5 is used to balance the bending moment brought by the winglet 4 to the blade 2 in the rotation plane.

[0020] Working principle:

[0021] When the rotor rotates rapidly, the blade 2 unfolds under the action of centrifugal force and aerodynamic force; when the rotor stops, the blade 2 bends and droops under the action of gravity, and the rotor diameter is much smaller or slightly smaller than the unfolded state. During flight, when the blade 2 rotates, it is driven by the winglet 4 and generates an angle of attack, thereby driving the airflow downward and generating lift. During the forward flight of the UAV, the flexible rotor deforms under the action of wind force, is not easily fatigued and damaged, and can reduce vibration; when encountering gusts, the flexible rotor can effectively eliminate the influence of gusts through flexible deformation, thereby reducing the vibration of the aircraft and improving the clarity of shooting and imaging. Larger gusts can also well eliminate their influence and improve the stability and safety of the UAV. When the blade encounters an obstacle, it can reduce the degree of damage through deformation.

[0022] As Figure 4 shown is a schematic diagram of the curve groove of another embodiment of the present invention.

[0023] The winglet mechanism is relatively heavy and will have a large centrifugal force. In order to prevent the winglet mechanism from being thrown off from the flexible blade, in this embodiment, a steel wire rope is embedded in the blade base material. The fixing of the steel wire rope to the winglet frame 5 adopts a friction fixing method. The winglet frame 5 is in an upper and lower half type. Curved grooves with a circular cross-section are correspondingly arranged on the inner sides of the two half winglet frames. The diameter of the steel wire rope is slightly smaller than the circular cross-section of the curved groove 7. The steel wire rope is inserted into the curved groove 7 of the winglet frame 5, covered with the other half winglet frame, and the two half winglet frames are pressed and fixed with bolts. Since the steel wire rope has large elasticity, when the steel wire rope bends in the curved groove, there will be a large elastic force acting on the curved groove wall. When the winglet device gives a large centrifugal force to the frame, the friction force between the steel wire rope and the curved groove wall provides the pulling force. By setting multiple turns on the curve, a large static friction force can be provided, and the winglet mechanism is fixed firmly and is not easily loosened and fallen off.

[0024] The above are the specific implementation manners of the present invention, but the protection scope of the present invention should not be limited thereto. Any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention should be subject to the protection scope defined by the claims.

Claims

1. A rotor based on flexible blades, with several blades evenly spaced on the rotor shaft, characterized in that, The blade is made of a flexible material, and high-strength tensile ropes are arranged therein. The blade reduces gust interference through deformation. A winglet mechanism is fixed at the wingtip of the blade, and a winglet is installed on the winglet mechanism. The winglet is arranged parallel to the blade. The winglet is provided with an angle of attack relative to the blade chord line for providing a torsional moment for the blade to have an angle of attack. The number of the winglets is two, and the winglets are symmetrically installed on both sides of the blade. A balance weight is also installed on the winglet mechanism, and the balance weight and the winglet are installed on both sides of the blade.

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