A flexible virtual dihedral semi-hinge rotor

Abstract

The application discloses a flexible virtual skew-axis semi-hinge rotor, which is arranged on an aircraft and comprises blades, a hub, a connecting module, a limiting and fastening device and a driving device. The connecting module is a flexible virtual skew-axis hinge, which adopts a skew-axis type composite hinge structure and is arranged between the hub and the driving device. The waist region of the X-shaped structure of the flexible virtual skew-axis hinge is arranged through cross three-dimensional weaving and multi-layer laying. The hinge shaft center of the flexible virtual skew-axis hinge is designed to be at a certain angle with the blade span direction. The hub is a symmetric structure with a concave middle part and two U-shaped side parts. The symmetric centers of the two U-shaped structures are coplanar with the hinge shaft of the flexible virtual skew-axis hinge, and the U-shaped structures are used for mounting and fixing the blades. The limiting device at the lower part of the hub is used for adjusting and limiting, so as to control the swing angle of the blades. The flexible virtual skew-axis semi-hinge rotor can self-recover balance and self-adapt to airflow changes, so as to offset torsion and vibration. The flexible virtual skew-axis semi-hinge rotor has the advantages of simple structure, no bearing, no friction, maintenance-free, self-damping, reduced vibration and high reliability.

Description

Technical Field

[0001] This application belongs to the field of aviation propulsion systems, and in particular relates to a flexible virtual slant-axis semi-hingeless rotor. Background Technology

[0002] Traditional seesaw-type or semi-hingeless rotors mostly use a double-ear metal hinge shaft structure, which has the following drawbacks: metal hinges require a lubrication system, are prone to wear after long-term use, and have high maintenance costs; moving parts are prone to noise and vibration, increasing metal fatigue; metal materials are prone to corrosion in humid environments, requiring surface plating or replacement with materials such as titanium alloys, increasing processing costs; the hinges have poor adaptability to dusty environments, and dust intrusion can easily lead to hinge shaft wear and failure; the structural design is complex, with many types of parts, making it difficult to achieve miniaturization. Utility Model Content

[0003] To address the shortcomings and problems of existing rotor technology, a technical solution is proposed to realize the function of a seesaw rotor by a virtual slanted hinge flexible rotor. By applying new materials to optimize the mechanical hinge structure of the seesaw propeller, a flexible virtual slanted axis semi-hingeless rotor with a simple structure, dynamic balancing of blade forces, adaptive adjustment of angle of attack, and reduced vibration is provided.

[0004] To solve the above technical problems, the technical solution adopted in this application is: a flexible virtual slant-axis semi-hingeless rotor, which is set on the upper end of the drive device of the aircraft, including blades, hub, connecting module, limiting and fastening, and drive device. The connecting module is a flexible virtual slant-axis hinge, which adopts a slant-axis composite hinge structure, and can flap, oscillate and change pitch within a small range, combining the functions of flapping hinge, oscillation hinge and pitch-changing hinge. The flexible virtual slant-axis hinge is installed between the hub and the drive device, including an upper seat, a lower base, a middle flexible virtual hinge and a damping block. The middle flexible virtual hinge connects the upper seat and the base through a middle X-shaped structure.

[0005] Furthermore, the flexible virtual oblique axis hinge X-shaped structure is configured as a biomimetic geometric shape optimized with a wasp waist. The X-shaped structure has a waist region that contracts in the middle and an outer contour that expands at both ends, and the virtual hinge axis of the flexible virtual oblique axis hinge is formed at the X intersection of the X-shaped structure.

[0006] Furthermore, the axis of the flexible virtual hinge is designed with a slant angle θ relative to the spanwise direction of the blade. The slant angle θ is an acute angle on the leading edge of the blade, so that the blade angle of attack decreases when the blade flaps upward and increases when the blade flaps downward, enabling the rotor to dynamically balance the blade force, self-recover balance, adaptively adjust the angle of attack, and reduce vibration; the slant angle θ is preferably 45°.

[0007] Furthermore, the flexible virtual oblique axis hinge employs various composite materials with different properties, different laying processes, or a combination of both, to ensure that the flexible virtual oblique axis hinge design exhibits high rigidity and minimal deformation in directions other than the axis of the flexible virtual hinge when twisted. The hinge area of ​​the X-shaped structure of the flexible virtual oblique axis hinge uses flexible resin fiber material, which has significant elasticity and can twist along the oblique axis, achieving the composite hinge function of the flexible virtual oblique axis chain. The surface layer of the flexible virtual oblique axis hinge uses flexible resin fiber woven fabric laid at ±45° cross-lay, while the internal reinforcement layer uses flexible resin fiber woven fabric strips laid in an "X" shape cross-lay to enhance the hinge structure strength and improve the shear and tear resistance of the flexible hinge. The central part uses flexible resin fiber unidirectional tape, laid symmetrically in a "C" shape, three-dimensionally crossing through the X-shaped hinge area to enhance the tensile and shear strength of the hinge. After the "X" shaped cross-lay and the "C" shaped symmetrical lay, the hollow area is filled with a short-cut fiber mixture to ensure the rigidity of the hub structure.

[0008] The damping blocks of the flexible virtual oblique axis hinge are bonded to both sides of the X-shaped structure of the flexible virtual oblique axis hinge, and the outer periphery is covered with flexible resin fiber woven fabric at ±45° cross-lay, thereby significantly increasing the damping characteristics of the flexible virtual oblique axis hinge.

[0009] The limiting and fastening of the flexible virtual slant-axis semi-hingeless rotor includes a limiting device and a fastening assembly. The limiting device is located at the lower part of the rotor hub and is used to limit the extreme angle of rotor hub swing. The fastening assembly includes a blade bolt assembly, a rotor hub bolt assembly, and a drive bolt assembly. The fastening assembly is a bolt assembly to prevent loosening and can effectively prevent bolts from coming loose. Furthermore, the fastening assembly uses thread-locking adhesive, locking washers, or lock nuts to prevent loosening.

[0010] The rotor hub of the flexible virtual slant-axis semi-hingeless rotor is configured as a U-shaped structure with a concave center and symmetrically extended sides. The center of symmetry of the U-shaped structures on both sides is on the same plane as the hinge axis of the flexible virtual slant-axis hinge, so that the change in the angle of attack of the blades on the left and right sides is equal in magnitude and opposite in direction, thus avoiding vibration. The blades are fixedly installed on the U-shaped structures on both sides. Preferably, the rotor hub adopts a high-strength composite material structure with embedded bushings. The bushings are embedded in the fastening holes to improve the contact strength, and can better reduce weight, avoid fatigue cracks, improve service life, and ensure reliability.

[0011] Furthermore, the hub bolt group secures the hub to the upper seat of the connecting module, and preferably the hub bolt group has a bolt set number of 4 or more; the drive bolt group secures the connecting module to the drive device, and preferably the drive bolt group has a bolt set number of 4 or more; the blade bolt group secures the blade to the U-shaped structures on both sides of the hub, and preferably each blade bolt group has a bolt set number of 2 or more.

[0012] The angle between the axis of the flexible virtual hinge and the blade slant angle affects the self-restoring balance capability of the rotor in this application. A larger angle results in a faster response and recovery, while a smaller angle results in a slower response and recovery. Generally, a 45° angle is designed. In the triangular balance of mechanical simplification, natural flight quality, and overall performance, a 45° slant angle is the globally optimal solution. Increasing the angle (>45°) is suitable for special UAVs with extreme agility requirements, but it requires bearing the risks of stability collapse, speed limitation, and structural imbalance. Decreasing the angle (<45°) is only used for specific scenarios that optimize hovering visibility (such as aerial photography UAVs), but it limits maneuverability and high-speed capability. Therefore, the slant angle θ of agile aircraft is 45-80°, preferably 50°; the slant angle θ of hovering optimization aircraft is 10-45°, preferably 30°.

[0013] Beneficial effects: 1. The core component of the flexible virtual slant-axis semi-hingeless rotor of this application, the flexible virtual slant-axis hinge, adopts a biomimetic geometric X-shaped structure, which adapts to airflow changes, counteracts torque and vibration, and reduces energy loss; 2. The flexible virtual slant-axis semi-hingeless rotor of this application has a simple structure, high reliability, and reduces manufacturing and maintenance costs; 3. The flexible hinge of the flexible virtual slant-axis semi-hingeless rotor of this application is frictionless, maintenance-free, bearingless, and dustproof, making it well-suited for dusty environments; 4. The flexible hinge of the flexible virtual slant-axis semi-hingeless rotor of this application uses flexible resin composite material, and also uses specially woven fabric strips cross-laid, which is lightweight, high-strength, fatigue-resistant, corrosion-resistant, and has inherent damping characteristics, which can reduce vibration and extend the service life of the entire system; 5. The flexible virtual slant-axis semi-hingeless rotor of this application is suitable for high-speed and complex airflow environments. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of a flexible virtual slanted axis semi-hingeless rotor structure.

[0015] Figure 2 This is an enlarged schematic diagram of the intermediate structure of a flexible virtual slanted-axis semi-hingeless rotor.

[0016] Figure 3 A schematic diagram of the flexible virtual slant-axis hinge structure of a flexible virtual slant-axis semi-hingeless rotor.

[0017] Figure 4 Layup diagram of flexible virtual slant-axis hinge X-type structure for flexible virtual slant-axis semi-hingeless rotor.

[0018] Figure 5 This is a cross-sectional view of the internal features of the flexible virtual slant-axis hinge of a flexible virtual slant-axis semi-hingeless rotor.

[0019] Figure 6 This is a schematic diagram of the slant axis angle of a flexible virtual slant axis semi-hingeless rotor.

[0020] The diagram is labeled as follows: 100-blade, 101-blade leading edge, 102-blade span; 200-hub, 201-U-shaped structure, 202-concave center, 203-hub insert; 300-connecting module / flexible virtual inclined axis hinge, 301-upper seat, 302-flexible virtual hinge, 303-base, 304-damping block, 305-flexible resin fiber woven strip; 306-flexible resin fiber unidirectional belt; 307-flexible resin fiber strip; 308-chopped fiber mixture; 309-hinge shaft, 310-hinge insert; 400-limiting and fastening, 401-blade bolt assembly, 402-hub bolt assembly, 403-drive bolt assembly, 404-limiting device; 500-drive device. Implementation

[0021] The technical solution of this application will be clearly and completely described below with reference to the accompanying drawings and embodiments. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0022] In the description of this application, it should be noted that the terms "center", "upper", "lower", "left", "right", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only used to simplify the description of this application and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0023] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0024] like Figure 1 , Figure 2 As shown, the flexible virtual slant-axis semi-hingeless rotor of this application is installed on the upper part of the aircraft, including blades 100, hub 200, connecting module 300, limit and fastening 400, and drive device 500. The connecting module 300 of the flexible virtual slant-axis semi-hingeless rotor is fixed to the upper end of the drive device 500 by a group of drive bolts 403. The flexible virtual slant-axis semi-hingeless rotor is driven to rotate around the axis by the rotation of the drive device 500.

[0025] Furthermore, such as Figure 3 As shown, the connecting module 300 is a flexible virtual oblique axis hinge, employing an oblique axis composite hinge structure. It is installed between the propeller hub 200 and the drive device 500, and includes an upper seat 301, a central flexible virtual hinge 302, a base 303, and a damping block 304. The central flexible virtual hinge 302 connects the upper seat 301 and the base 302 via a central X-shaped structure. The X-shaped structure is designed with a biomimetic geometric shape optimized to resemble a wasp waist. This X-shaped structure has a constricted waist region in the middle and an expanded outer contour at both ends. The X-shaped structure guides the load along this path, reducing local stress concentration.

[0026] Furthermore, such as Figure 4 , Figure 5 As shown, the waist region of the X-structure of the flexible virtual hinge 302 uses a metal-free flexible resin composite material, which increases the elastic deformation of the flexible hinge and completely solves the problem of metal corrosion.

[0027] Furthermore, the surface of the X-shaped hinge area of ​​the flexible virtual hinge 302 is covered with flexible resin fiber woven fabric strips 307 at ±45°, and the interior is a reinforcing layer covered with flexible resin fiber woven fabric strips 305 in an “X” shape, which strengthens the hinge structure and improves the shear resistance and tear resistance of the flexible hinge.

[0028] Furthermore, the X-shaped hinge area of ​​the flexible virtual hinge 302 is symmetrically laid in a "C" shape with flexible resin fiber unidirectional tape 306 through the hinge area to enhance the tensile and shear strength of the hinge.

[0029] Furthermore, the hollow areas after the “X”-shaped cross-laying and the “C”-shaped symmetrical laying are filled with short-cut fiber mixture 308 to ensure the structural rigidity of the connecting module 300.

[0030] Furthermore, the rubber damping element 304 is bonded to the outside of the X-shaped structure of the flexible virtual hinge 302, and flexible fiber woven strips 307 are laid in an "X" shape on the periphery to increase the overall bonding strength. The damping block 304 can significantly increase the damping characteristics of the flexible virtual hinge 302. Preferably, the damping block 304 is a rubber damping block.

[0031] like Figure 4 , 6As shown, the narrowest part of the X-shaped span of the flexible virtual oblique axis hinge forms the hinge axis 309. The hinge axis 309 and the blade 100 are designed with a certain oblique axis angle θ in the span. The oblique axis angle θ is an acute angle on the blade leading edge 101 side, so that the blade 100 can reduce the angle of attack when flapping upward and increase the angle of attack when flapping downward, and has the function of self-recovering neutral position. The oblique axis angle θ is generally designed to be 45°. In the triangular balance of mechanical simplification, natural flight quality and full-line package performance, the 45° seesaw structure is the global optimal solution. Increasing the angle (>45°) is suitable for special UAVs with extreme agility requirements, but it is necessary to bear the risk of stability collapse, speed limitation and structural imbalance. Decreasing the angle (<45°) is only used for specific scenarios to optimize hovering vision (such as aerial photography UAVs), but the handling performance and high-speed capability are limited.

[0032] The limiting and fastening includes a limiting device 404 and a fastening assembly. The limiting device 404 is located at the lower part of the propeller hub 200 and can be adjusted to limit and control the maximum swing angle of the propeller blade 100 to prevent excessive deflection. The fastening assembly includes a blade bolt assembly 401, a hub bolt assembly 402, and a drive bolt assembly 403. Furthermore, the fastening assembly is a bolt assembly designed to prevent loosening and can effectively prevent the bolts from coming loose. Furthermore, the fastening assembly uses thread-locking adhesive, locking washers, or lock nuts to prevent loosening.

[0033] The propeller hub 200, such as Figure 1 , 2 As shown, the structure is a U-shaped structure with a concave center and symmetrically extended sides. The center of symmetry of the U-shaped structure at both ends is on the same plane as the hinge axis of the flexible virtual oblique axis hinge. The U-shaped structure is used to install and fix the blade 100, and two blade bolt groups 401 are provided to pass through the hub 200 and the blade 100 for fixation. When the hub 200 rotates around the axis, it drives the blade 100 fixed at both ends to rotate. The blade 100 flaps freely up and down in the plane of rotation. Due to the lateral airflow brought by the forward flight, the forward blade 100 (the side with higher airflow speed) flaps upward due to the increased lift, resulting in its effective attack... The angle decreases, thus reducing lift; the backward blade 100 (on the side with lower airflow velocity) flaps downward, increasing the angle of attack to compensate for the lift loss. This automatic flapping motion balances the aerodynamic lift difference on both sides by changing the geometric angle of the blade 100, reducing vibration and maintaining overall force equilibrium. Furthermore, when the blade 100 rotates, centrifugal force causes the blade 100 to extend outward, and the huge centrifugal force is always parallel to the plane of rotation. When the blade 100 flaps, the centrifugal force generates a restoring torque, which pulls the flapping blade 100 back to the plane of rotation, forming an equivalent spring and achieving self-balancing. Preferably, the hub 200 adopts a high-strength composite material structure with embedded bushings. Bushings are embedded in all fastening holes to improve contact strength, reduce weight, avoid fatigue cracks, improve service life, and ensure reliability.

[0034] Furthermore, the central recess 202 of the propeller hub 200 is provided with a plurality of fastening connection holes for connection and fastening. The fastening connection holes adopt a sleeve structure, and the propeller hub nest 203 is embedded in the central recess 202 of the propeller hub 200 to improve the contact strength of the connection and facilitate the passage of the propeller hub bolt group 402; furthermore, the number of fastening connection holes is greater than 4.

[0035] Furthermore, the upper seat 301 of the flexible virtual slant-axis hinge 300 is matched and installed in the concave 202 in the middle of the rotor hub 200; furthermore, the upper seat 301 is provided with a threaded hole that matches the rotor hub sleeve 203 in the concave 202 in the middle of the rotor hub 200, and the rotor hub bolt group 402 passes through the through hole of the rotor hub 200 and screws into the threaded hole of the upper seat 301 of the flexible virtual slant-axis hinge, thereby fixing the flexible virtual slant-axis hinge 300 and the rotor hub 200; the base 303 of the flexible virtual slant-axis hinge 300 is provided with a plurality of symmetrical through hole structures, which facilitates the passage of the drive bolt group 403 and screws into the upper end of the drive device 500, thereby fixing the flexible virtual slant-axis hinge 300 and the drive device 500; furthermore, the number of through holes in the base 303 is greater than 4; furthermore, the fastener connection hole of the flexible virtual slant-axis hinge 300 adopts a sleeve structure, and the hinge nest 310 is embedded in the flexible virtual slant-axis hinge 300, thereby improving the contact strength of the connection.

[0036] Furthermore, such as Figure 4 , 5 As shown, the flexible virtual hinge 302 of the flexible virtual inclined axis hinge 300 is provided with damping blocks 304 bonded on both sides and wrapped with flexible fiber woven fabric 307. While improving the bonding strength, it also increases the damping characteristics of the flexible hinge, which can also absorb vibration energy and reduce the vibration of the entire system. The blade 100 swings synchronously to change the airflow distribution and improve propulsion efficiency.

[0037] Working principle: During rotation, changes in airflow cause uneven force on the blades on both sides, causing the flexible virtual hinge 302 of the flexible virtual slant axis hinge 300 to undergo elastic deformation, triggering the flexible virtual slant axis semi-hingeless rotor to generate self-recovering mid-position flapping, dynamically adjusting the angle of attack to achieve torque balance, thereby counteracting torque and vibration.

[0038] The above description is merely a preferred embodiment of this application and is not intended to limit the scope of protection of this application. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application are included within the scope of protection of this application.

Claims

1. A flexible virtual slant-axis semi-hingeless rotor, mounted on an aircraft, comprising blades, a hub, a connecting module, a limiting and fastening mechanism, and a drive device, characterized in that: The connection module is a flexible virtual oblique axis hinge, which adopts an oblique axis composite hinge structure. The flexible virtual oblique axis hinge is installed between the propeller hub and the drive device and includes an upper seat, a base, a middle flexible virtual hinge and a damping block. The middle flexible virtual hinge connects the upper seat and the base through a middle X-shaped structure.

2. The flexible virtual slant-axis semi-hingeless rotor according to claim 1, characterized in that: The flexible virtual oblique axis hinge X-shaped structure is a biomimetic geometric optimization structural design. The X-shaped structure has a waist region that contracts in the middle and an outer contour that expands at both ends. The flexible virtual hinge of the flexible virtual oblique axis hinge is formed at the X intersection of the X-shaped structure.

3. A flexible virtual slant-axis semi-hingeless rotor according to claim 2, characterized in that: The axis of the flexible virtual hinge is designed to be at an oblique angle θ with respect to the span of the blade, and the oblique angle θ is an acute angle on the leading edge side of the blade.

4. A flexible virtual slant-axis semi-hingeless rotor according to claim 2, characterized in that: The flexible virtual oblique axis hinge uses a variety of composite materials and a variety of laying processes. The surface layer is made of flexible resin fiber woven fabric laid at ±45° cross-lay. The inner layer is a reinforcing layer made of flexible resin fiber woven fabric strips laid in an "X" shape with cross-lay. The central part uses flexible resin fiber unidirectional tape laid in a "C" shape with symmetrical cross-lay. The cross-lay passes through the X-shaped hinge area in three dimensions. After the "X" shaped cross-lay and the "C" shaped symmetrical cross-lay, the hollow area is filled with a mixture of short-cut fibers.

5. A flexible virtual slant-axis semi-hingeless rotor according to any one of claims 1-4, characterized in that: The damping block is bonded to both sides of the flexible virtual oblique axis hinge X-shaped structure, and the periphery is covered with flexible resin fiber woven fabric at ±45° cross-lay; furthermore, the damping block is a rubber damping block.

6. The flexible virtual slant-axis semi-hingeless rotor according to claim 1, characterized in that: The limiting and fastening includes a limiting device and a fastening assembly. The limiting device is located at the lower part of the propeller hub to limit the extreme angle of the propeller hub. The fastening assembly includes a blade bolt assembly, a propeller hub bolt assembly, and a drive bolt assembly. The fastening assembly is a bolt assembly to prevent loosening.

7. A flexible virtual slant-axis semi-hingeless rotor according to claim 1, characterized in that: The propeller hub is configured as a U-shaped structure with a concave center and symmetrically extended sides. The center of symmetry of the U-shaped structure on both sides is on the same plane as the hinge axis of the flexible virtual oblique axis hinge. The U-shaped structure is used to install and fix the propeller blade.

8. A flexible virtual slant-axis semi-hingeless rotor according to claim 6, characterized in that: The hub bolt group secures the hub to the upper seat of the connecting module, and the hub bolt group has a bolt assembly number of 4 or more. The drive bolt group secures the connecting module to the drive device, and the drive bolt group has a bolt assembly number of 4 or more. The blade bolt group secures the blade to the U-shaped structures on both sides of the hub, and each blade bolt group has a bolt assembly number of 2 or more.

9. A flexible virtual slant-axis semi-hingeless rotor according to claim 3, characterized in that: The slant angle θ is 45° in conventional aircraft; the slant angle θ is 45-80° in agile aircraft; and the slant angle θ is 10-45° in hovering-optimized aircraft.

10. A flexible virtual slant-axis semi-hingeless rotor according to any one of claims 1, 6, and 7, characterized in that: The propeller hub adopts a high-strength composite material structure with embedded bushings.

Images