Unmanned aerial vehicle rotor wing with super-hydrophobic microstructure on surface and forming method of unmanned aerial vehicle rotor wing

Abstract

The invention relates to an unmanned aerial vehicle rotor wing with a super-hydrophobic microstructure on the surface and a forming method thereof, aiming at the unmanned aerial vehicle rotor wing, the unmanned aerial vehicle rotor wing comprises a porous curved plate, and the surface of the porous curved plate is densely covered with holes and is used as a core material of the rotor wing; the micron-sized rough surface structure layer is made of a thermoplastic composite material, covers the surface of the porous curved plate and serves as a surface layer of the rotor wing; the reinforcing body is made of a thermoplastic composite material, the holes of the porous curved plate are filled with the reinforcing body, and the reinforcing body and the micron-sized rough surface structure layer are integrally formed. The forming method for the rotor wing of the unmanned aerial vehicle comprises the following steps that S1, stamping and shaping operation is executed, and S2, cleaning operation is executed; s3, executing surface activation treatment operation; s4, injection molding operation is executed, and a micro mold is used for wrapping the porous curved plate subjected to the previous operation; and a carbon fiber grid layer or a glass fiber grid layer is wound and fixed on the surface of the porous curved plate. The unmanned aerial vehicle rotor surface solid-liquid separation device is beneficial to unmanned aerial vehicle rotor surface solid-liquid separation and ice prevention.

Description

Technical Field

[0001] The present invention relates to the field of unmanned aerial vehicle (UAV) rotors, and in particular to a UAV rotor with a super-hydrophobic microstructure on the surface.

[0002] The invention also relates to a method for forming the rotor of the UAV. Background Art

[0003] With the booming development of the low-altitude economy, drones are increasingly used in many fields, such as logistics distribution, agricultural plant protection, aerial photography and mapping. Under the general framework of the low-altitude economy, the frequency of drone flights and the complexity of the operating environment have increased significantly. When drones fly in low temperature or humid environments, the rotor surface is prone to ice, which will change the aerodynamic characteristics of the rotor, increase the weight and mass distribution of the rotor, and thus affect the flight performance and controllability of the drone. The shedding of ice may also damage other parts of the drone, increasing the risk of flight.

[0004] Existing deicing technologies include electric deicing, liquid anti-icing and pneumatic deicing. Electric deicing has high efficiency, but high energy consumption and complex system; liquid anti-icing has low energy consumption, but short action time and low anti-icing efficiency; pneumatic deicing system has low energy consumption, but limited installation locations, and may cause aerodynamic losses and reduce the fatigue life of the rotor. Summary of the invention

[0005] The purpose of the present invention is to provide a UAV rotor with a super-hydrophobic microstructure on the surface, which has a self-cleaning function. It utilizes the super-hydrophobic structure to achieve solid-liquid separation, which is beneficial to the anti-icing of the rotor. It also has a sandwich structure filled with reinforcing materials to improve stiffness and strength and stabilize the super-hydrophobic structure of the surface layer.

[0006] Another object of the present invention is to provide a method for forming the above-mentioned drone rotor with a super-hydrophobic microstructure on the surface, which is convenient for manufacturing the required drone rotor.

[0007] Regarding the technical topic of drone rotors with super-hydrophobic microstructures on the surface, it includes: The porous curved panel, which has dense holes on its surface, serves as the core material of the rotor; A micron-scale rough surface structure layer, which is made of thermoplastic composite material and coated on the surface of the porous curved panel, serves as the surface layer of the rotor; The reinforcement body is made of thermoplastic composite material and filled in the holes of the porous curved panel. The reinforcement body is integrally formed with the micron-level rough surface structure layer.

[0008] As a further improvement of the UAV rotor, a carbon fiber mesh layer or a glass fiber mesh layer is wound and fixed on the surface of the porous curved panel.

[0009] Regarding the technical topic of the molding method, it specifically includes the following steps: S1: Perform stamping and shaping operations to produce porous curved panels as the core material of the UAV rotor; S2: performing a cleaning operation, placing the porous curved panel executed in step S1 into a cleaning machine for cleaning; S3: performing a surface activation treatment operation, placing the porous curved panel executed in step S2 into a plasma surface treatment device for surface activation treatment; S4: Perform injection molding operation, use a micro mold to cover the porous curved panel that has completed the previous step of operation, reserve a gap between the porous curved panel and the inner wall of the cavity of the micro mold, and the inner wall of the cavity of the micro mold is distributed with micron-level depressions. Inject the thermoplastic composite material into the micro mold through an injection molding machine, and open the mold after pressure holding and cooling; obtain a drone rotor with a micron-level rough surface structure.

[0010] As a further improvement of the forming method, the porous curved panel is made of stainless steel plate.

[0011] As a further improvement of the forming method, in S2, the porous curved panel is washed and then dried by a hot air dryer; In S3, the surface activation treatment operation is performed under an inert gas atmosphere.

[0012] As a further improvement of the forming method, in step S1, in the stamping and shaping operation, the porous curved panel is processed into the contour shape of the finished UAV rotor by using a stamping die, but the contour size is smaller than that of the finished UAV rotor, so as to reserve space for the surface layer to be filled by the core material.

[0013] As a further improvement of the molding method, the cleaning machine in S2 is an ultrasonic cleaning machine.

[0014] As a further improvement of the forming method, the previous step operation in S4 is: A1: Perform carbon fiber or glass fiber winding operation, use a winding machine to wind carbon fiber filaments or glass fiber filaments on the porous curved panel after executing step S3, and fix them by bonding with an adhesive; the specific operation method is to perform fiber filament winding operation and adhesive brushing operation in a cycle, and the fiber filaments are wound in two layers at two angles to form a mesh layer.

[0015] As a further improvement of the molding method, the UAV rotor finished product includes two pairs of UAV rotor blades and a rotor shaft ring therebetween. In step S4, the porous curved panel is supported in the cavity of the micro-mold by friction fixing in which a limit pin or a limit protrusion is filled in the rotor shaft ring, so as to reserve space required for injection molding of the surface layer on the surface of the cavity. When a limit pin is used, the limit pin passes through the micro-mold and is sealed at the passing position. When a limit protrusion is used, the limit protrusion is fixed in the cavity of the micro-mold.

[0016] As a further improvement of the molding method, the thermoplastic composite material is made of nylon as the base material and one or two of glass fiber and carbon fiber as the reinforcing material.

[0017] The present invention is conducive to improving the strength of UAV rotors at low cost, realizing rotor anti-icing more conveniently, simplifying the rotor forming process of professional UAVs and realizing mass production, which is of great significance for promoting the efficient, safe and extensive application of UAVs in various fields of low-altitude economy.

[0018] Compared with the prior art, the present invention has the following advantages: Compared with the molding of traditional UAV rotors, the present invention uses a stainless steel porous curved panel and winds glass fiber or carbon fiber as the core material reinforcement in the sandwich structure, and glass fiber or carbon fiber is also added to the thermoplastic composite material as a reinforcement material, so that the mechanical properties of the UAV rotor are more excellent; because the thermoplastic composite material completely covers the core material, the resulting product has good appearance quality; and because the core material is a stainless steel porous curved panel with a certain number of holes, after injection molding, the thermoplastic composite material and the core material have stronger bonding performance and are not easy to peel off, making the entire sandwich structure more solid. Since the micro-injection molding method is adopted, the present invention can obtain the super-hydrophobic microstructure of the rotor surface at one time, and more conveniently achieve the goal of hydrophobic anti-icing; compared with coating the hydrophobic material on the rotor surface, the surface microstructure obtained by injection molding is not easy to fall off or fail, and the anti-icing effect is more durable. Injection molding also has the advantages of simple process, easier to obtain complex-shaped rotors, and mass production. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 is a schematic diagram of a stainless steel porous curved panel having a rotor profile shape.

[0020] Figure 2 It is a partial enlarged view of a stainless steel porous curved panel wrapped with glass fiber or carbon fiber.

[0021] Figure 3 This is a schematic diagram of the drone rotor.

[0022] Figure 4 yes Figure 3 Side view of the local microstructure of the surface indicated by mark 1.

[0023] Figure 5 It is a schematic diagram of the forming process of the UAV rotor.

[0024] Figure numerals: 1, UAV rotor; 1A, rotor shaft ring. DETAILED DESCRIPTION

[0025] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0026] In the description of the present invention, it should be noted that the orientations or positional relationships indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. are based on the orientations or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the devices or elements referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention; the terms "first", "second", and "third" are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance; in addition, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be a communication between the two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0027] Example 1 like Figure 1-Figure 4 As shown, a drone rotor with a super-hydrophobic microstructure on the surface comprises: The porous curved panel, which has dense holes on its surface, serves as the core material of the rotor; A micron-scale rough surface structure layer, which is made of thermoplastic composite material and coated on the surface of the porous curved panel, serves as the surface layer of the rotor; The reinforcement body is made of thermoplastic composite material and filled in the holes of the porous curved panel. The reinforcement body is integrally formed with the micron-level rough surface structure layer.

[0028] In this embodiment, a carbon fiber mesh layer or a glass fiber mesh layer is wound and fixed on the surface of the porous curved panel.

[0029] Example 2 like Figure 5 As shown, a method for forming a UAV rotor with a super-hydrophobic microstructure on the surface comprises the following steps: S1: Perform stamping and shaping operations to produce porous curved panels as the core material of the UAV rotor; S2: performing a cleaning operation, placing the porous curved panel executed in step S1 into a cleaning machine for cleaning; S3: performing a surface activation treatment operation, placing the porous curved panel executed in step S2 into a plasma surface treatment device for surface activation treatment; S4: Perform injection molding operation, use a micro mold to cover the porous curved panel that has completed the previous step of operation, reserve a gap between the porous curved panel and the inner wall of the cavity of the micro mold, and the inner wall of the cavity of the micro mold is distributed with micron-level depressions. Inject the thermoplastic composite material into the micro mold through an injection molding machine, and open the mold after pressure holding and cooling; obtain a drone rotor with a micron-level rough surface structure.

[0030] In this embodiment, the porous curved panel is made of stainless steel plate.

[0031] In this embodiment, in S2, the porous curved panel is dried by a hot air dryer after being cleaned; In S3, the surface activation treatment operation is performed under an inert gas atmosphere.

[0032] In this embodiment, in step S1, in the stamping and shaping operation, the porous curved panel is processed into the contour shape of the finished UAV rotor by using a stamping die, but the contour size is smaller than that of the finished UAV rotor, so as to reserve space for the surface layer to be filled by the core material.

[0033] In this embodiment, the cleaning machine in S2 is an ultrasonic cleaning machine.

[0034] In this embodiment, the previous step in S4 is: A1: Perform carbon fiber or glass fiber winding operation, use a winding machine to wind carbon fiber filaments or glass fiber filaments on the porous curved panel after executing step S3, and fix them by bonding with an adhesive; the specific operation method is to perform fiber filament winding operation and adhesive brushing operation in a cycle, and the fiber filaments are wound in two layers at two angles to form a mesh layer.

[0035] In this embodiment, the finished UAV rotor includes two pairs of UAV rotor blades and a rotor shaft ring therebetween. In step S4, the porous curved panel is supported in the cavity of the micro-mold by a friction fixation method in which a limit pin or a limit protrusion is filled in the rotor shaft ring, so as to reserve space required for injection molding of the surface layer on the surface of the cavity. When a limit pin is used, the limit pin passes through the micro-mold and is sealed at the passing position. When a limit protrusion is used, the limit protrusion is fixed in the cavity of the micro-mold.

[0036] In this embodiment, the thermoplastic composite material is made of nylon as a base material and one or two of glass fiber and carbon fiber as a reinforcing material.

[0037] Example 3 A method for molding a UAV rotor with a super-hydrophobic microstructure on the surface, which is used for injection molding a high-strength anti-icing UAV rotor, comprises the following steps: (1) Select a stainless steel porous curved panel as the reinforcing material. When manufacturing a small UAV rotor, a stainless steel porous curved panel with a thickness of 0.5 mm and a mesh size of R = 5 mm is selected; when manufacturing a large UAV rotor, a stainless steel porous curved panel with a thickness of 2 mm and a mesh size of R = 20 mm is selected. The stainless steel porous curved panel is placed in a stamping machine for shearing and stamping. The stainless steel porous curved panel is processed into a rotor core material with a shape consistent with the rotor and a size slightly smaller than the rotor through a stamping die. The porous curved panel is smaller than the finished rotor to reserve space for injection molding to form a surface layer.

[0038] (2) Clean the rotor core material formed by the stainless steel porous curved plate. Place the rotor core material in an ultrasonic cleaner and clean it in deionized water for 5 minutes to remove grease and dust on the surface. After cleaning, dry the rotor core material in a hot air dryer.

[0039] (3) The cleaned rotor core material is immediately subjected to surface activation treatment. The dried rotor core material is placed in a plasma treatment device and treated in an argon atmosphere for 30 seconds to introduce polar groups on the metal surface to increase the adhesion between the stainless steel porous curved panel and the thermoplastic composite material. (4) Winding the glass fiber or carbon fiber filaments onto the stainless steel porous curved panel. During the winding process, a dedicated winding device is used to ensure the uniformity and tightness of the glass fiber or carbon fiber filaments, but a certain gap is left to form a grid so that the thermoplastic composite material can pass through these gaps during subsequent injection molding. During the winding process, an appropriate adhesive such as epoxy resin structural adhesive is used to fix the glass fiber or carbon fiber filaments onto the stainless steel porous curved panel to ensure that the glass fiber or carbon fiber filaments will not fall off during the subsequent injection molding process.

[0040] (5) To avoid re-oxidation of the core material surface, the treated core material should be immediately injection molded. The core material is fixed in the micro mold cavity, and the inner surface of the cavity is evenly distributed with depressions with a spacing of 20 μm and a diameter of 10 μm. This mold can form papillae of corresponding size on the rotor surface to obtain the desired superhydrophobic microstructure.

[0041] The size of the core material is slightly smaller than the size of the mold cavity. After it is placed in the injection mold cavity, a certain gap is left between the stainless steel porous curved plate and the mold cavity. The purpose of this is that during the injection molding process, the thermoplastic composite material can surround and fill these gaps from all sides, so that the stainless steel porous curved plate is completely covered in the injection molded rotor. The appropriate fixing method can ensure good bonding between the stainless steel porous curved plate and the plastic matrix, while avoiding internal stress caused by differences in thermal expansion coefficients, thereby improving the mechanical properties and durability of the rotor.

[0042] Appropriate fixing methods can be achieved through the following solutions, such as using the limit pins and positioning holes in the mold design to assist in positioning the stainless steel porous curved plate, or designing a specific protrusion structure in the mold cavity to support the stainless steel porous curved plate to keep it in the appropriate position. In this embodiment, a limit protrusion is designed in the mold cavity to fix the core material. The position of the limit protrusion is Figure 3 It corresponds to 1A in the middle, so this is the rotor shaft hole, which is the part connected to the drone. It is a through hole itself and does not require filling material. The raised structure fills the rotor shaft hole and is fixed by friction.

[0043] (6) After the core material is fixed, the mold is closed and the screw of the injection molding machine moves forward to inject the molten nylon and glass fiber or carbon fiber short filament material into the mold cavity; the glass fiber or carbon fiber short filament is added with a feeder to control the amount of material added. The material flows in the cavity, fills the cavity and covers the stainless steel porous curved plate. During the pressure holding stage, a certain pressure is maintained to ensure that the material is fully filled and reduce the generation of bubbles. During the cooling stage, the cooling system inside the mold starts to work, so that the injection molded part is quickly cooled and solidified. Finally, the mold is opened and the molded rotor is taken out.

[0044] Example 4 This embodiment is the molding of a small drone, and a stainless steel porous curved panel is selected as the reinforcing material, with a thickness of 0.5mm and a mesh size of R=5mm. The stainless steel porous curved panel is placed in a punching machine for shearing and punching, and the stainless steel porous curved panel is processed into a core material with a shape consistent with the rotor and a size slightly smaller than the rotor. The core material is placed in an ultrasonic cleaner for cleaning; the cleaned core material is dried by a hot air dryer; the dried core material is immediately treated in an argon atmosphere for 30 seconds using a plasma treatment device.

[0045] Nylon PA6 (15% glass fiber or carbon fiber is added by the feeder) is used as the injection material during injection molding to improve the strength and rigidity of the rotor. The surface of the injection mold cavity is evenly distributed with depressions with a spacing of 20μm and a diameter of 10μm, so that the surface of the injection molded product has a super-hydrophobic microstructure similar to a lotus leaf of corresponding size. In the injection molding process parameters, the barrel temperature is set to 280°C and the mold temperature is set to 70°C to ensure the fluidity and filling of the material. The injection pressure is set to 70MPa to ensure that the material can fully fill the microstructure of the mold. The holding time is set to 5s to ensure that the material is completely filled in the mold cavity. The cooling time is set to 15s to ensure that the rotor is completely cooled and solidified before opening the mold. Finally, open the mold and take out the molded rotor.

[0046] Example 5 This embodiment is suitable for the forming of large unmanned aerial vehicle rotors, and a stainless steel porous curved panel is selected as the reinforcing material, with a thickness of 5mm and a mesh size of R=20mm. The stainless steel porous curved panel is placed in a stamping machine for shearing and stamping, and the stainless steel porous curved panel is processed into a core material with a shape consistent with the rotor and a size slightly smaller than the rotor through a stamping die. The core material is placed in an ultrasonic cleaner for cleaning; the cleaned core material is dried by a hot air dryer; the dried core material is immediately treated in an argon atmosphere for 30 seconds using a plasma treatment device. Use a special winding equipment to evenly wind the glass fiber or carbon fiber filament onto the activated core material, and use epoxy resin structural adhesive as a binder to fix the glass fiber or carbon fiber on the metal mesh.

[0047] During injection molding, reinforced nylon PA6 (10% glass fiber or carbon fiber is added by the feeder) is used as the injection material to improve the strength and rigidity of the rotor. The surface of the injection mold cavity is evenly distributed with depressions with a spacing of 20μm and a diameter of 10μm, so that the surface of the injection molded product has a super-hydrophobic microstructure similar to a lotus leaf of corresponding size. In the injection molding process parameters, the barrel temperature is set to 280°C and the mold temperature is set to 70°C to ensure the fluidity and filling of the material. The injection pressure is set to 70MPa to ensure that the material can fully fill the microstructure of the mold. The holding time is set to 10s to ensure that the material is completely filled in the mold cavity. The cooling time is set to 25s to ensure that the rotor is completely cooled and solidified before opening the mold. Finally, open the mold and take out the molded rotor.

[0048] The tensile strength of the prepared UAV rotor reached 150 MPa and the elongation at break was 5%, showing good strength and toughness. The impact strength was 8 kJ / m, indicating that it has good energy absorption capacity when subjected to impact. The static contact angle of the rotor surface reached 150 degrees and the rolling angle was 10 degrees, indicating that it has excellent hydrophobic properties. When the rotor rotates at high speed, water droplets and ice layers can fall off quickly, indicating that its hydrophobic structure effectively promotes the de-icing of the rotor.

[0049] This embodiment demonstrates a method for forming a UAV rotor with a super-hydrophobic microstructure on the surface. This method embeds a stainless steel porous curved panel inside the rotor and winds glass fiber or carbon fiber as the core material, and adds glass fiber or carbon fiber to the injection molding material, so that various performances can be enhanced, and a super-hydrophobic microstructure is formed on the surface, which significantly improves the strength and anti-icing performance of the rotor. At the same time, the use of injection molding technology makes the production of the rotor more efficient and economical, and is suitable for large-scale production. The quality and performance of the rotor are ensured by reasonable injection molding process parameters.

[0050] The above contents are further detailed descriptions of the present invention in combination with specific preferred embodiments, and it cannot be determined that the specific implementation of the present invention is limited to these descriptions. For those skilled in the art of the present invention, several equivalent substitutions or obvious variations can be made without departing from the concept of the present invention, and the performance or use is the same, which should be regarded as belonging to the protection scope of the present invention.

Claims

1. A drone rotor with a super-hydrophobic microstructure on the surface, characterized in that include: The porous curved panel, which has dense holes on its surface, serves as the core material of the rotor; A micron-scale rough surface structure layer, which is made of thermoplastic composite material and coated on the surface of the porous curved panel, serves as the surface layer of the rotor; The reinforcement body is made of thermoplastic composite material and filled in the holes of the porous curved panel. The reinforcement body is integrally formed with the micron-level rough surface structure layer.

2. The UAV rotor with a super-hydrophobic microstructure on the surface according to claim 1, characterized in that A carbon fiber mesh layer or a glass fiber mesh layer is wound and fixed on the surface of the porous curved panel.

3. A method for forming a drone rotor with a super-hydrophobic microstructure on the surface, characterized in that The specific steps include: S1: Perform stamping and shaping operations to produce porous curved panels as the core material of the UAV rotor; S2: performing a cleaning operation, placing the porous curved panel executed in step S1 into a cleaning machine for cleaning; S3: performing a surface activation treatment operation, placing the porous curved panel executed in step S2 into a plasma surface treatment device for surface activation treatment; S4: Perform injection molding operation, use a micro mold to cover the porous curved panel that has completed the previous step of operation, reserve a gap between the porous curved panel and the inner wall of the cavity of the micro mold, and the inner wall of the cavity of the micro mold is distributed with micron-level depressions. Inject the thermoplastic composite material into the micro mold through an injection molding machine, and open the mold after pressure holding and cooling; obtain a drone rotor with a micron-level rough surface structure.

4. The method for forming a UAV rotor with a super-hydrophobic microstructure on the surface according to claim 3, characterized in that The porous curved panel is made of stainless steel plate.

5. The method for forming a drone rotor with a super-hydrophobic microstructure on the surface according to claim 4, characterized in that In S2, the porous curved panel is dried by a hot air dryer after being cleaned; In S3, the surface activation treatment operation is performed under an inert gas atmosphere.

6. The method for forming a drone rotor with a super-hydrophobic microstructure on the surface according to claim 3, characterized in that In step S1, in the stamping and shaping operation, the porous curved panel is processed into the contour shape of the finished UAV rotor by using a stamping die, but the contour size is smaller than that of the finished UAV rotor to reserve space for the surface layer to be filled by the core material.

7. The method for forming a drone rotor with a super-hydrophobic microstructure on the surface according to claim 3, characterized in that The cleaning machine in S2 is an ultrasonic cleaning machine.

8. The method for forming a drone rotor with a super-hydrophobic microstructure on the surface according to claim 3, characterized in that The previous operation in S4 is: A1: Perform carbon fiber or glass fiber winding operation, use a winding machine to wind carbon fiber filaments or glass fiber filaments on the porous curved panel after executing step S3, and fix them by bonding with an adhesive; the specific operation method is to perform fiber filament winding operation and adhesive brushing operation in a cycle, and the fiber filaments are wound in two layers at two angles to form a mesh layer.

9. The method for forming a drone rotor with a super-hydrophobic microstructure on the surface according to claim 6, characterized in that The finished UAV rotor includes two pairs of UAV rotor blades and a rotor shaft ring therebetween. In step S4, the porous curved panel is supported in the cavity of the micro-mold by a friction fixation method in which a limit pin or a limit protrusion is filled in the rotor shaft ring, so as to reserve space required for injection molding of the surface layer on the surface of the cavity. When a limit pin is used, the limit pin passes through the micro-mold and is sealed at the passing position. When a limit protrusion is used, the limit protrusion is fixed in the cavity of the micro-mold.

10. The method for forming a drone rotor with a super-hydrophobic microstructure on the surface according to claim 3, characterized in that The thermoplastic composite material is made of nylon as a base material and one or two of glass fiber and carbon fiber as a reinforcing material.

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