Single-motor ornithopter

Abstract

This utility model discloses a single-motor ornithopter, including a fuselage, a wing, and a tail fin mounted on the fuselage. A two-stage reduction gearbox is mounted on the fuselage, and a wing pivot connector and a rhomboid frame are mounted externally on the two-stage reduction gearbox. The two-stage reduction gearbox includes a primary reduction shaft system and a secondary reduction shaft system. The wing pivot connectors are symmetrically arranged on both sides of the secondary large gear, and the rhomboid frames are positioned between the sides of the wing pivot connectors. The sides of the rhomboid frames are rotatably connected to the sides of the wing pivot connectors. Each wing pivot connector is rotatably equipped with a swing fork, and each swing fork is rotatably connected to the secondary large gear on the same side via a single-plate revolute joint, causing the swing fork to swing left and right as the secondary large gear rotates. This utility model features a modular design for easy assembly and an optimized shaft system design to ensure no displacement of the shaft system and no lateral oscillation of the gears, thus improving the flight stability of the ornithopter.

Description

Technical Field

[0001] This utility model relates to the field of biomimetic flapping-wing robot technology, and in particular to a single-motor flapping-wing robot. Background Technology

[0002] Ornithopter aircraft are a type of aircraft that achieve flight by mimicking the flapping of birds' or insects' wings. Unlike traditional fixed-wing aircraft or rotary-wing UAVs, ornithopter aircraft rely on regular wing flapping to generate lift and thrust, thereby achieving hovering, forward movement, turning and other flight maneuvers. This flight mode has strong biomimetic characteristics and has become a hot topic in aerodynamics, bionics and UAV research in recent years. Among them, single-motor ornithopter aircraft usually achieve synchronous flapping of the wings with a single rotary actuator and mechanical transmission. This technical route aims to obtain usable lift and thrust and better stability with fewer actuators and electronic components, and the core lies in the selection of the transmission mechanism. However, the development of single-motor ornithopter aircraft still has certain defects: (1) Many existing ornithopter mechanism designs do not consider modularity and simple design, making it difficult to achieve quick and convenient disassembly and assembly; (2) Existing ornithopter mechanisms and transmission designs are too redundant and complex, resulting in a heavy fuselage and affecting flight efficiency; (3) Most existing designs do not consider the shaft positioning design of the ornithopter transmission mechanism, making it difficult to ensure the stability of the mechanism during operation.

[0003] For example, CN117284513A discloses a single-motor driven multimodal flapping wing aircraft. A single motor drives the wheel via a two-stage gear system, transmission shaft, and linkage, and works in conjunction with a spatial five-link system to achieve a 3D flapping trajectory around an ellipse at the wingtip. A single servo motor drives the tail fin to provide directional control, achieving a minimal actuator configuration in conjunction with the aforementioned single-motor main drive. However, during flight, the electromagnet right-angle connecting shaft design requires "coaxial movable connection" with the drive wheel, drive rod, and other multi-hole locations. This structure poses risks regarding loosening under vibration loads, gap evolution, and long-term durability, easily introducing micro-backlash and phase errors, affecting the accuracy and efficiency of the flapping trajectory. Therefore, there is an urgent need for a single-motor flapping wing aircraft with a modular design for easy assembly and optimized shaft system design, especially axial positioning design, to ensure no shaft displacement and lateral gear wobbling, thereby improving flight stability. Utility Model Content

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and to provide a single-motor flapping wing aircraft with a modular design for easy assembly and optimized design of the shaft system, especially the axial positioning design, to ensure that there is no displacement of the shaft system and lateral sway of the gears, thereby improving flight stability.

[0005] To achieve the above objectives, this utility model is implemented through the following technical solution:

[0006] A single-motor flapping-wing aircraft includes a fuselage, a wing, and a tail fin mounted on the fuselage. A two-stage reduction gearbox is mounted on the fuselage. Externally, the two-stage reduction gearbox includes a wing pivot connector and a rhomboid frame. The two-stage reduction gearbox comprises a motor, a primary large gear, and a secondary large gear. A primary drive gear meshes with the primary large gear on the motor's output shaft. Secondary small gears are rigidly connected coaxially to both sides of the primary large gear, and each secondary small gear meshes with a secondary large gear. The wing pivot connectors are symmetrically positioned on both sides of the secondary large gears. The rhomboid frame is positioned between the sides of the wing pivot connectors, and the sides of the rhomboid frame are rotatably connected to the sides of the wing pivot connectors. Each wing pivot connector is rotatably equipped with a swing fork, and each swing fork is rotatably connected to the secondary large gear on the same side via a slotted joint, causing the swing fork to swing left and right as the secondary large gear rotates. A wing connector, connected to the wing, is fixedly mounted on the wing pivot connector.

[0007] Furthermore, the bottom surface of the tail fin is provided with a vertical wing, the front end of the tail fin is rotatably connected to the fuselage through a tail fin connector, the tail fin connector is provided with a servo for controlling the swing of the vertical wing, the rear end of the top rod of the vertical wing is provided with a vertical wing swing member, the vertical wing swing member is slidably engaged with the arc-shaped rod on the rear side of the tail fin, and the trailing edge of the tail fin is arc-shaped.

[0008] Furthermore, a first central shaft is coaxially arranged at the center of the secondary large gear. The middle part of the first central shaft is fixed to the machine body through two carbon plate hole thickening parts. Each carbon plate hole thickening part is fitted with a flange bearing on its outer side. Each flange bearing abuts against the secondary large gear on the same side through a graphite gasket and a bushing.

[0009] Furthermore, the first-stage large gear and the second-stage small gear are coaxially provided with a second central shaft. The two ends of the second central shaft are mounted on the shaft fixing parts outside the machine body through flange bearings. A sleeve is provided between the second-stage small gear and the flange bearing to abut against the inner ring of the flange bearing.

[0010] Furthermore, the swing fork is rotatably connected to the wing shaft connector via concentric knurled pins and flange sleeves.

[0011] Furthermore, the two ends of the wing pivot connector are rotatably connected to the diamond frame via pins, sleeves, and flange bearings, and the pins are made of Teflon material.

[0012] Furthermore, a pin cover is fixedly provided on the side of the rhomboid frame and is rotatably connected to the side end of the wing pivot connector.

[0013] Compared with the prior art, the present invention has the following beneficial effects:

[0014] This invention employs a two-stage gear reduction system, consisting of a primary reduction shaft system centered on a primary large gear and a secondary reduction shaft system centered on a secondary large gear. Axial positioning has been optimized to ensure no axial displacement of the flapping-wing aircraft and no lateral oscillation of the gears, thus guaranteeing the stability of the transmission mechanism during flight. The fuselage, secondary reduction gearbox, wings, and tail are all modularly designed, facilitating assembly, modular manufacturing, and replacement. The combination of the tail and vertical wing provides pitch stability during flight and allows for control of fuselage turning by adjusting the vertical wing's oscillation. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the structure of this utility model;

[0016] Figure 2 This is a schematic diagram of the structure of the two-stage reduction gearbox in this utility model;

[0017] Figure 3 for Figure 2 Side view;

[0018] Figure 4 This is a schematic diagram of the connection structure between the motor and the first-stage large gear in this utility model;

[0019] Figure 5 This is a diagram showing the internal structure of the secondary large gear in this utility model;

[0020] Figure 6 This is a diagram showing the internal structure of the primary gear in this utility model;

[0021] Figure 7 This is a top view of the linkage mechanism in this utility model;

[0022] Figure 8 for Figure 7 A cross-sectional view along the DD direction;

[0023] Figure 9 This is a structural diagram showing the connection between the wing pivot connector and the rhomboid frame in this utility model.

[0024] Figure 10 This is a structural diagram showing the connection between the wing pivot connector and the swing fork in this utility model.

[0025] Figure 11 This is a schematic diagram of the wing structure in this utility model;

[0026] Figure 12 This is a schematic diagram of the tail fin structure in this utility model.

[0027] Figure label:

[0028] 1-Two-stage reduction gearbox; 2-Fuselage; 3-Wing; 4-Tail; 5-Vertical wing; 6-Servo; 7-Tail wing connector; 8-Vertical wing swing component; 11-Motor; 12-First-stage drive gear; 13-First-stage large gear; 14-Second-stage small gear; 15-Second-stage large gear; 16-First central shaft; 17-Flange bearing; 18-Carbon plate hole thickening component; 19-Graphite gasket; 20-Nylon gasket; 21-Second central shaft; 22-Sleeve; 23-Shaft fixing component; 24-Swing fork; 25-Wing pivot connector; 26-Wing connector; 27-Knurled pin; 28-Flange sleeve; 29-Rhomboid frame; 30-Pin; 31-Pin cover. Detailed Implementation

[0029] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0030] like Figures 1 to 12 As shown, a single-motor flapping-wing aircraft includes a fuselage 2, a wing 3 and a tail fin 4 mounted on the fuselage 2. A two-stage reduction gearbox is mounted on the fuselage 2. A wing pivot connector 25 and a diamond-shaped frame 29 are externally mounted on the two-stage reduction gearbox. The two-stage reduction gearbox includes a motor 2, a primary large gear 13, and a secondary large gear 15. A primary drive gear 12 meshes with the primary large gear 13 on the output shaft of the motor 2. Secondary small gears 14 are rigidly connected coaxially on both sides of the primary large gear 13. Each secondary small gear 14 is connected to a secondary large gear 15. Gears 15 mesh; the wing pivot connectors 25 are symmetrically arranged on both sides of the secondary large gear 15, and the rhomboid frames 29 are arranged between the sides of the wing pivot connectors 25. The sides of the rhomboid frames 29 are rotatably connected to the side ends of the wing pivot connectors 25. Each wing pivot connector 25 is rotatably provided with a swing fork 24. Each swing fork 24 is rotatably connected to the secondary large gear 15 on the same side through a straight rotating joint, so that the swing fork 24 swings left and right as the secondary large gear 15 rotates. A wing connector 26 connected to the wing 3 is fixedly provided on the wing pivot connector 25.

[0031] like Figure 12As shown, the bottom surface of the tail fin 4 is provided with a vertical wing 5. The front end of the tail fin 5 is rotatably connected to the fuselage 2 via a tail fin connector 7. A servo 6 for controlling the swing of the tail fin 4 is provided on the tail fin connector 7. A vertical wing swing member 8 is provided at the rear end of the top rod of the vertical wing 5. The vertical wing swing member 8 is in sliding engagement with the arc-shaped rod on the rear side of the tail fin 4. The trailing edge of the tail fin 5 is arc-shaped. The combination of the tail fin 4 and the vertical wing 5 can provide stability for flight pitch and can also control the turning of the fuselage 2 by adjusting the swing of the vertical wing 5. The tail fin 4 is connected to the fuselage 2 via the tail fin connector 7, which not only makes it easy to remove the tail fin 4, but also allows the servo 6 to be removed directly. Compared with most tail fin mechanisms that arrange the drive in the fuselage and then drive it through a transmission mechanism, the modular design of this patent facilitates assembly and replacement.

[0032] The vertical wing 5 is directly driven by the servo motor 6, but its relatively long length leads to a significant cantilever effect. To address this, the trailing edge of the tail wing 4 is designed as an arc, with its center being the rotation center of the servo motor 6. This allows the vertical wing 5 to be connected to the trailing edge of the tail wing 4 via a vertical wing swing mechanism, enabling a sliding fit between the two. The vertical wing swing mechanism serves both to support the tail wing membrane and to support the rotation of the vertical wing.

[0033] This invention employs a two-stage gear reduction system, consisting of a primary reduction shaft system and a secondary reduction shaft system. The primary drive gear 12 on the output shaft of motor 11 meshes with a primary large gear 13 to complete the primary reduction. The primary large gear 13 is rigidly connected coaxially to two symmetrical secondary small gears 14 on both sides, rotating synchronously. The secondary small gears 14 mesh with two symmetrical secondary large gears 15 to complete the secondary reduction. A linkage mechanism then converts the rotational motion output from the secondary reduction gearbox into flapping motion. Specifically, the rotation of the secondary large gear 15 drives the swing fork 24 to swing back and forth. When the swing fork 24 swings, it drives the wing pivot connector 25 to tilt and rotate up and down. The wing 3 further flaps via the wing connector 26, driven by the wing pivot connector 25. The wing 3 and fuselage 2 are connected by a pivot seat to achieve the flapping motion.

[0034] like Figure 5 As shown, a first central shaft 16 is coaxially arranged at the center of the secondary large gear 15. The middle part of the first central shaft 16 is fixed to the machine body 2 through two carbon plate hole thickening parts 18. Each carbon plate hole thickening part 18 is fitted with a flange bearing 17 on its outer side. Each flange bearing 17 abuts against the secondary large gear 15 on the same side through a graphite gasket 19. In this embodiment, the first central shaft 16 is a threaded pin. Bolts are fixedly connected to both sides of the threaded pin. The bolts are pressed onto the threaded pin by nylon gaskets 20, and the secondary reduction shaft system is fixed by the bolts.

[0035] The secondary reduction shaft system is the power output shaft system. Its structure is the opposite of the primary shaft system, adopting a "fixed in the middle, rotating at both ends" design to meet the needs of power output to both wings. The first central shaft 16 is fixed to the fuselage 2 through two carbon plate hole thickening parts 18. Two flange bearings 17 are fitted on the outer side of the carbon plate hole thickening parts 18. The flange bearings 17 abut against the secondary large gear 15 on the same side through graphite gaskets 18. The graphite gaskets 18 have a large contact area, which can provide effective support for the secondary large gear 15, thereby ensuring the stability and durability of the output shaft system. The outermost part uses two bolts to press all components onto the first central shaft 16 through nylon gaskets 20.

[0036] like Figure 6 As shown, the primary large gear 13 and the secondary small gear 14 are coaxially mounted on a second central shaft 21. Both ends of the second central shaft 21 are mounted on shaft fixing components 23 outside the machine body 2 via flange bearings 17. A sleeve 22 is provided between the secondary small gear 14 and the flange bearings 17, abutting against the inner ring of the flange bearings 17. In this embodiment, the second central shaft 21 is a threaded pin, and bolts at both ends of the shaft system lock the threaded pin to all intermediate components, ensuring the stability of the second central shaft 21.

[0037] The primary reduction shaft system adopts a "fixed at both ends, rotating in the middle" design. A threaded pin with internal threads serves as the second central shaft 21. Both ends are mounted on the shaft system fixing component 23 via two flange bearings 17. Between the two flange bearings 17 is a primary large gear 13 and two secondary small gears 14. The inner side of the secondary small gears 14 is rigidly connected to the primary large gear 13 as a whole via a groove and glue groove, while the outer side is held against the inner ring of the flange bearings 17 by two sleeves 22, used for precise axial positioning of the entire rotating part to prevent it from moving along the shaft.

[0038] like Figures 7 to 10 As shown, the swing fork 24 is rotatably connected to the wing pivot connector 25 via concentric knurled pins 27 and flange sleeves 28 to ensure synchronous swinging of the swing fork 24 and the wing pivot connector 25. Both ends of the wing pivot connector 25 are rotatably connected to the rhomboid frame 29 via pins 30, sleeves 22, and flange bearings 17. The pins 30 are made of Teflon. Although there is dry friction between the end face of the pin 30 and the fixed end face of the swing fork 24 due to the extremely low coefficient of friction of Teflon, this friction loss is completely acceptable. A pin cover 31 is fixedly provided on the side of the rhomboid frame 29, rotatably connected to the side end of the wing pivot connector 25. The pin cover 31 can limit the axial movement of the pin 30. The modular design facilitates assembly, and the stable support provided by the rhomboid frames on both sides ensures smooth and reliable movement of the mechanism.

[0039] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A single-motor ornithopter, comprising a fuselage (2), and a wing (3) and a tail fin (4) disposed on the fuselage (2), characterized in that: The fuselage is equipped with a two-stage reduction gearbox. The exterior of the two-stage reduction gearbox is fitted with a wing pivot connector (25) and a rhomboid frame (29). The two-stage reduction gearbox includes a motor (11), a primary large gear (13), and a secondary large gear (15). The output shaft of the motor (11) is equipped with a primary drive gear (12) that meshes with the primary large gear (13). Symmetrically coaxially rigidly connected to both sides of the primary large gear (13) are secondary small gears (14), each of which meshes with a secondary large gear (15). The wing pivot connector (25)... Symmetrically arranged on both sides of the secondary gear (15), the rhomboid frame (29) is arranged between the sides of the wing pivot connector (25), the side of the rhomboid frame (29) is rotatably connected to the side of the wing pivot connector (25), and each wing pivot connector (25) is rotatably provided with a swing fork (24). Each swing fork (24) is rotatably connected to the secondary gear (15) on the same side through a single rotating joint, so that the swing fork (24) swings left and right as the secondary gear (15) rotates. A wing connector (26) connected to the wing (3) is fixedly provided on the wing pivot connector (25).

2. The single-motor flapping-wing aircraft according to claim 1, characterized in that: The bottom surface of the tail wing (4) is provided with a vertical wing (5). The front end of the tail wing (4) is rotatably connected to the fuselage (2) through the tail wing connector (7). The tail wing connector (7) is provided with a servo (6) to control the swing of the vertical wing (5). The rear end of the top rod of the vertical wing (5) is provided with a vertical wing swing member (8). The vertical wing swing member (8) slides and engages with the arc-shaped rod on the rear side of the tail wing (4). The trailing edge of the tail wing (4) is arc-shaped.

3. A single-motor flapping-wing aircraft according to claim 1, characterized in that: The second-stage large gear (15) is coaxially provided with a first central shaft (16). The middle part of the first central shaft (16) is fixed to the machine body (2) through two carbon plate hole thickening parts (18). Each carbon plate hole thickening part (18) is fitted with a flange bearing (17) on its outer side. Each flange bearing (17) is abutted against the second-stage large gear (15) on the same side through a graphite gasket (19) and a bushing.

4. A single-motor flapping-wing aircraft according to claim 1, characterized in that: The first-stage large gear (13) and the second-stage small gear (14) are coaxially provided with a second central shaft (21). The two ends of the second central shaft (21) are mounted on the shaft fixing parts (23) outside the machine body (2) through flange bearings (17). A sleeve (22) is provided between the second-stage small gear (14) and the flange bearing (17) to abut against the inner ring of the flange bearing (17).

5. A single-motor flapping-wing aircraft according to claim 1, characterized in that: The swing fork (24) is rotatably connected to the wing pivot connector (25) via concentric knurled pins (27) and flange sleeves (28).

6. A single-motor flapping-wing aircraft according to claim 1, characterized in that: The two ends of the wing pivot connector (25) are rotatably connected to the rhomboid frame (29) via pins (30), sleeves (22) and flange bearings (17), and the pins (30) are made of Teflon material.

7. A single-motor flapping-wing aircraft according to claim 6, characterized in that: The side of the rhomboid frame (29) is fixedly provided with a pin cover (31) that is rotatably connected to the side end of the wing pivot connector (25).

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