A two-degree-of-freedom wing folding and unfolding mechanism and a design method thereof, and a two-degree-of-freedom wing aircraft

Abstract

The application discloses a two-degree-of-freedom wing folding and unfolding mechanism and a design method thereof and a two-degree-of-freedom wing aircraft, and belongs to the technical field of folding wing aircrafts, and solves the technical problems of complex structure and poor stability of the existing wing folding and unfolding mechanism. The wing folding and unfolding mechanism comprises a worm wheel, a support, a large cylindrical gear, a small cylindrical gear, a worm, a driving motor, a rotating shaft, a fixed shaft, a first clutch, a second clutch, a sliding block and a sliding rail. The wing is installed on the support through the rotating shaft, the sliding rail and the rack are installed on the fuselage, and the support is connected with the sliding rail through the second clutch and the sliding block. The design method comprises the steps of worm and worm gear set transmission parameter design, spur cylindrical gear set transmission parameter design, center distance variable coefficient calculation and wing translation design. The aircraft comprises the two-degree-of-freedom wing folding and unfolding mechanism, the wing and the fuselage. The application is used for folding wing aircraft design.

Description

Technical Field

[0001] This invention belongs to the technical field of folding wing aircraft, specifically relating to a two-degree-of-freedom wing folding mechanism and its design method, and a two-degree-of-freedom wing aircraft. Background Technology

[0002] With the development of the drone industry, the application prospects of drones in civilian and commercial fields are gradually emerging. Drone equipment characterized by lightweight, agile portability, and low cost has become one of the main development directions. In the storage, transportation, and use of drones, wing folding can significantly improve space utilization; therefore, mastering wing folding technology is particularly important.

[0003] Traditional wing folding mechanisms often use springs as the driving component, but after long-term storage, the elasticity can easily decrease, causing jamming during the unfolding process and affecting the stability during unfolding.

[0004] Traditionally, the wings fold horizontally. During the design process, the wings need to be deliberately positioned on the upper or lower part of the fuselage and staggered vertically. Designs that place the wings in the middle of the fuselage will intrude into the cabin space and affect the rigidity of the aircraft fuselage and the stability during flight.

[0005] Traditional wing folding mechanisms that use gear transmission often employ gears and racks. Motion control of the second degree of freedom often requires the design of a separate power source. This design increases weight, reduces flight economy and range, and increases the manufacturing cost and complexity of the drone.

[0006] Chinese invention patent CN121734654A discloses a servo structure for a micro-sized folding-wing aircraft. In this invention, the wing unfolds in two steps via a compression spring and a worm gear. It does not unfold under a single power source; the drive device includes a motor and a compression spring. The spur gear set is used only as a reducer for the motor-driven worm shaft and as a feedback mechanism for the deflection angle. Because the folding process of this mechanism is performed in steps, simultaneous unfolding would result in motion interference.

[0007] Chinese invention patent CN116788508A discloses a tilt-folding-variable pitch self-locking rotor and method for shaft-fan power. It utilizes the self-locking characteristics of a worm gear to drive the rotor to unfold in a predetermined direction, with the direction of motion horizontal to a predetermined plane. However, this patent controls the rotor pitch angle through a hydraulic transmission method using a variable pitch piston, resulting in a complex structure.

[0008] Chinese invention patent CN116119052B discloses a fixed-wing UAV with foldable wings, which uses a worm gear to synchronize the folding of the tail fin and the wing, simultaneously achieving 90° rotation in two axes. However, this method does not achieve two degrees of freedom motion for a single wing, resulting in high mechanism complexity.

[0009] Chinese utility model patent CN209921595U discloses a spanwise folding mechanism for a drone and the drone itself, which uses a worm gear to drive a connecting rod on the wing to achieve uniform spanwise folding. However, this design only has a single degree of freedom, resulting in a limited range of wing movements.

[0010] Chinese invention patent CN116280172A discloses a low-cost folding wing deployment mechanism that uses a rack and pinion drive and an air pump to deploy the wing, achieving both swept-back parallel deployment and wing-direction deployment simultaneously. However, this deployment mechanism uses an air pump as a secondary power source, resulting in high complexity and manufacturing costs. Summary of the Invention

[0011] To overcome the shortcomings of existing wing folding mechanisms, such as complex structure and poor stability, this invention proposes a two-degree-of-freedom wing folding mechanism, its design method, and a two-degree-of-freedom wing aircraft.

[0012] To meet the portable transportation requirements of drones, this design reduces costs while increasing space utilization, and simultaneously ensures the airframe strength and stability during flight.

[0013] The technical solution adopted by this invention to solve its technical problem is:

[0014] A two-degree-of-freedom wing folding and unfolding mechanism includes a worm gear, a bracket, a large cylindrical gear, a small cylindrical gear, a worm, a drive motor, a rotating shaft, a fixed shaft, a first clutch, a second clutch, a slider, a slide rail, and a rack.

[0015] The wing is fixedly connected to the rotating shaft, which is mounted on a bracket via bearings.

[0016] The bracket is an integral structure, including a bracket body and a bracket shaft, with the bracket body located at the top and the bracket shaft at the bottom. The drive motor and the rotating shaft are respectively mounted on the bracket body.

[0017] The worm gear is coaxial with the rotating shaft and is connected by a key.

[0018] The drive motor output shaft, fixed shaft, and small cylindrical gear are sequentially and fixedly connected, with the small cylindrical gear meshing with the large cylindrical gear. The drive motor drives the fixed shaft and small cylindrical gear to rotate. The drive motor output shaft is connected to the worm gear via a second clutch, which is used to engage and disengage the drive motor output shaft from the worm gear. The worm gear meshes with a worm wheel.

[0019] The slide rail and rack are fixedly mounted on the machine body, and the slider is mounted on the slide rail and moves along the slide rail. The rack meshes with a large cylindrical gear, which is connected to the support shaft through a bearing. The large cylindrical gear and the support shaft are coaxial.

[0020] A first clutch is provided between the large cylindrical gear and the slide rail. The first clutch is used to engage or disengage the large cylindrical gear and the slide rail, or to engage or disengage the support shaft and the slider.

[0021] In the aforementioned dual-degree-of-freedom wing folding mechanism, the worm gear and worm mesh to form a worm gear set, and the large cylindrical gear and small cylindrical gear mesh to form a spur gear set. The transmission ratio of the worm gear set is the same as that of the spur gear set.

[0022] The large cylindrical gear and the rack have the same module and the same pressure angle.

[0023] In the aforementioned two-degree-of-freedom wing folding mechanism, the worm drives the worm wheel to rotate. The worm wheel and worm gear set has a transmission ratio of 5, a module of 2.5, and a center distance of 51.5 mm. The worm has 6 threads, and the worm wheel has 30 teeth.

[0024] The small spur gear drives the large spur gear. The spur gear set has a module of 1, a pressure angle of 20°, and a center distance of 51.5 mm. The small spur gear has 17 teeth and a pitch circle diameter of 17 mm. The large spur gear has 85 teeth and a pitch circle diameter of 85 mm.

[0025] The center distance variation coefficient is -0.5.

[0026] A two-degree-of-freedom winged aircraft includes a two-degree-of-freedom wing folding mechanism, as well as a wing and a fuselage.

[0027] The wings and fuselage are connected by a two-degree-of-freedom wing folding mechanism.

[0028] The wing can translate back and forth relative to the fuselage, or rotate along the vertical direction of the wing center or in the wing direction.

[0029] In the aforementioned dual-degree-of-freedom winged aircraft, the wings, when folded, are located on both sides of the fuselage.

[0030] A design method for a two-degree-of-freedom wing folding mechanism includes the following steps:

[0031] Step 1, Design of worm gear transmission parameters

[0032] The worm drives the worm wheel to rotate. The transmission parameters of the worm wheel and worm gear set are as follows:

[0033]

[0034]

[0035] In the above formula, This refers to the transmission ratio of the worm gear set. This refers to the number of teeth on the worm gear. The number of worm gear threads. The center distance of the worm gear set. The module of the worm gear set. This is the worm diameter coefficient.

[0036] Step 2, Design of transmission parameters for spur gear sets

[0037] The small cylindrical gear drives the large cylindrical gear to rotate. The transmission parameters of the spur gear set are as follows:

[0038]

[0039]

[0040]

[0041]

[0042] In the above formula, This refers to the transmission ratio of a spur gear set. The number of teeth for a large cylindrical gear. This refers to the number of teeth on the small cylindrical gear. The center distance of a spur gear set. The module of a spur gear set. The pitch circle diameter of the small cylindrical gear. The pitch circle diameter of the large cylindrical gear.

[0043] Step 3: Calculate the center distance variation coefficient of the spur gear set.

[0044] Center distance variation coefficient of spur gear set The expression is:

[0045]

[0046] In the above formula, The center distance variation coefficient, This refers to the center distance of the worm gear set, i.e., the actual center distance. This refers to the center distance of the spur gear set, i.e., the design center distance. 2 represents the module of the spur gear set.

[0047] Step 4, Wing translation design

[0048] The large cylindrical gear and the rack have the same module and the same pressure angle.

[0049] The beneficial effects of this invention are:

[0050] A two-degree-of-freedom wing folding mechanism uses an electric motor as the input power source to realize the simultaneous rotation of the wing along the vertical direction of the wing center and the wing direction.

[0051] A two-degree-of-freedom wing folding and unfolding mechanism uses the same power source to realize the forward and backward translation of the wing, thereby achieving aircraft trim and improving aircraft maneuverability, safety and economy.

[0052] A two-degree-of-freedom wing folding mechanism eliminates the need for an alternating vertical wing design, thereby improving flight stability and aircraft aerodynamics.

[0053] A two-degree-of-freedom wing folding mechanism is disclosed, in which the folded wings are located on both sides of the fuselage without intruding into the internal space of the fuselage, thereby improving the fuselage strength during flight.

[0054] A design method for a two-degree-of-freedom wing folding mechanism, by designing the pressure angle of the worm gear, exhibits a self-locking stability effect or frequent folding characteristics, and is applicable to a wide range of designs.

[0055] A design method for a two-degree-of-freedom wing folding mechanism is presented, which features a simple form, a single power source, and low cost. This improves space utilization and transportation efficiency during aircraft transport and storage. Attached Figure Description

[0056] Figure 1 This is an isometric view of a two-degree-of-freedom wing folding mechanism according to Embodiment 1 of the present invention;

[0057] Figure 2 This is an isometric view of the rear of the dual-degree-of-freedom wing folding mechanism according to Embodiment 1 of the present invention;

[0058] Figure 3 This is a front view of a two-degree-of-freedom wing folding mechanism according to an embodiment of the present invention;

[0059] Figure 4 This is a left view of a two-degree-of-freedom wing folding mechanism according to an embodiment of the present invention;

[0060] Figure 5 This is a top view of a two-degree-of-freedom wing folding mechanism according to an embodiment of the present invention;

[0061] Figure 6 This is a schematic diagram of the overall structure of the dual-degree-of-freedom wing folding mechanism according to Embodiment 1 of the present invention.

[0062] The attached figures are labeled as follows:

[0063] 1. Worm gear; 2. Wing; 3. Support; 4. Large cylindrical gear; 5. Small cylindrical gear; 6. Worm; 7. Drive motor; 8. Key; 9. Fuselage; 10. Rotating shaft; 11. Fixed shaft; 12. First clutch; 13. Second clutch; 14. Slider; 15. Slide rail; 16. Rack. Detailed Implementation

[0064] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0065] Example 1

[0066] A two-degree-of-freedom wing folding mechanism, such as Figures 1 to 6 As shown, it includes a worm gear 1, a bracket 3, a large cylindrical gear 4, a small cylindrical gear 5, a worm 6, a drive motor 7, a key 8, a rotating shaft 10, a fixed shaft 11, a first clutch 12, a second clutch 13, a slider 14, a slide rail 15, and a rack 16.

[0067] A two-degree-of-freedom winged aircraft, such as Figure 6 As shown, it includes wing 2, fuselage 9, and a two-degree-of-freedom wing folding mechanism.

[0068] The positions of the bracket 3, worm gear 1, and drive motor 7 are relatively fixed; the rotating shaft 10 is connected to the worm gear 1 by a key 8, and is connected to the corresponding position on the bracket 3 by a bearing, so that the worm gear 1 and the wing 2 can rotate around the rotating shaft 10 at the same time; the output shaft of the drive motor 7 and the small cylindrical gear 5 are fixedly connected by a fixed shaft 11, and are connected to the worm 6 by a second clutch 13, wherein the second clutch 13 refers to a diaphragm spring clutch.

[0069] The bracket 3 is an integral structure, including the bracket body and the bracket shaft, with the bracket body located at the top and the bracket shaft at the bottom. The drive motor 7 and the rotating shaft 10 are respectively mounted on the bracket body.

[0070] The support shaft of bracket 3 is mounted with a large cylindrical gear 4 via bearings, allowing bracket 3 to rotate around its support shaft. The first clutch 12 consists of two sets of diaphragm spring clutches connected in parallel. The operation of the two clutches is independent of each other and they are coaxially assembled. The clutch connecting the support shaft of bracket 3 and the slider 14 is located on the inner side of the coaxial axis, while the clutch connecting the large cylindrical gear 4 and the slide rail 15 is located on the outer side of the coaxial axis. The first clutch 12 has two operating modes: mode one connects the large cylindrical gear 4 to the slide rail 15, and mode two connects the support shaft of bracket 3 to the slider 14. The slide rail 15 is fixed to the fuselage 9 to allow the mechanism to move in a specified direction. The slider 14 is connected to the support shaft of bracket 3, can rotate around the support shaft, and engages with the slide rail 15. The rack 16 is fixed to the fuselage 9. When the first clutch 12 disconnects the connection between the large cylindrical gear 4 and the slide rail 15 and engages the support shaft of bracket 3 and the slider 14, the wing 2 can achieve forward and backward translational movement.

[0071] During the wing folding motion, upon reaching the designated area, the second clutch 13 engages, and the drive motor 7 receives an electrical signal, simultaneously driving the worm 6 and the small cylindrical gear 5, which is fixedly connected to the motor output shaft, to rotate. Driven by the worm 6, the worm wheel 1 rotates, causing the wing 2, connected via key 8, to rotate around the rotation axis 10. Simultaneously, since the first clutch 12 selects mode one, engaging the large cylindrical gear 4 with the slide rail 15, the small cylindrical gear 5, during its rotation, drives the interconnected and fixed bracket 3, drive motor 7, worm 6, second clutch 13, and worm wheel 1 to rotate vertically, causing the wing 2 to rotate along with it. It is worth noting that the transmission ratio of the worm gear set and the spur gear set should be designed to maintain the same value to ensure synchronization and stability during deployment. The worm gear set includes the worm wheel 1 and the worm 6, while the spur gear set includes the large cylindrical gear 4 and the small cylindrical gear 5.

[0072] During the wing's translational movement, the first clutch 12 selects mode two, disengaging the large cylindrical gear 4 from the slide rail 15 and engaging the support shaft of the bracket 3 with the slider 14. The second clutch 13 is disengaged, meaning the drive motor only drives the small cylindrical gear 5 and not the worm gear 6, which affects the wing's rotation. Upon reaching the designated scene, the drive motor 7 receives an electrical signal, causing the small cylindrical gear 5, connected to the fixed shaft 10, to rotate, thereby rotating the large cylindrical gear 4 meshing with the small cylindrical gear 5. Since the large cylindrical gear 4 meshes with the rack 16, and the rack 16 is fixed to the fuselage 9, the wing 2 achieves forward and backward translational movement under the guidance of the slider 14 and the slide rail 15. It is worth noting that the slider 14 must be square to prevent the support shaft of the bracket 3 from rotating, thus avoiding rotation of the wing 2 during translation.

[0073] This two-degree-of-freedom wing folding mechanism boasts advantages such as smooth operation, high precision, and fast response. Based on the consistent transmission ratio of the worm gear set and the spur gear set, the wing synchronously completes two-degree-of-freedom rotational motion during folding. After folding, the wings are distributed on both sides of the fuselage, reducing space occupation, effectively shrinking the fuselage size, and improving the transport efficiency and space utilization of fixed-wing UAVs. The foldable mechanism designed in this invention is easy to control and use, has a small folded size, and the wing folding does not intrude into the internal space of the fuselage, ensuring fuselage strength and facilitating current battlefield and civilian carrying requirements. Simultaneously, dynamic trim can be achieved through the forward and backward horizontal movement of the wings, realizing a dynamic balance in improving maneuverability, safety, and economy.

[0074] Example 2

[0075] A design method for a worm gear-driven, two-degree-of-freedom wing folding mechanism and aircraft. During the wing's rotation and folding process, by setting various parameters of the worm gear, the spur gear set is reverse-engineered to determine the design scheme.

[0076] The specific process of this embodiment is as follows:

[0077] Step 1, Design of worm gear transmission parameters

[0078] Before the wing rotates and folds, upon reaching the designated scene, the second clutch 13 engages, the drive motor 7 receives an electrical signal, and drives the worm 6 to rotate. Simultaneously, the worm 6 drives the worm wheel 1 to rotate, causing the wing, connected to the worm wheel 1 via key 8, to rotate along the rotation axis 10. The specific design parameters of the worm gear set are as follows:

[0079]

[0080]

[0081] in, This refers to the transmission ratio of the worm gear set. This refers to the number of teeth on the worm gear. The number of worm gear threads. The center distance of the worm gear set. The module of the worm gear set. This is the worm diameter coefficient.

[0082] Step 2: Design the relevant parameters of the spur gear set.

[0083] While the worm gear 6 is driven by the torque of the drive motor 7, the small cylindrical gear 5, which is fixed to the drive motor 7, also begins to rotate under force. At this time, the first clutch 12 engages the large cylindrical gear 4 with the slide rail 15. Therefore, during the rotation of the small cylindrical gear 5, it will drive the interconnected bracket 3, worm wheel 1, worm gear 6, drive motor 7, key 8, wing 2, and second clutch 13 to rotate along the axis of rotation with the central axis of the large cylindrical gear 4 as the rotation axis. The specific design parameters of the spur gear set are as follows:

[0084]

[0085]

[0086]

[0087]

[0088] in, This refers to the transmission ratio of a spur gear set. The number of teeth for a large cylindrical gear. This refers to the number of teeth on the small cylindrical gear. The center distance of a spur gear set. The module of a spur gear set. The pitch circle diameter of the small cylindrical gear. The pitch circle diameter of the large cylindrical gear.

[0089] It is worth noting that the transmission ratio of the worm gear set and the spur gear set should be kept consistent to ensure coordinated rotation angles during operation.

[0090] Step 3: Consider the center distance difference between the worm gear set and the spur gear set and perform compensation design.

[0091] To ensure a tight fit between the worm gear set and the spur gear set, and to prevent undercutting if the center distance is less than the design value or impact during operation if the center distance is greater than the design value, a center distance variation coefficient is considered in the design process to ensure smooth and orderly operation. Specifically:

[0092] The center distance variation coefficient of a spur gear set is:

[0093]

[0094] in, The center distance variation coefficient, This is the center distance of the worm gear set, i.e., the actual center distance; This refers to the center distance of the spur gear set, i.e., the design center distance. 2 represents the module of the spur gear set.

[0095] When the center distance variation coefficient is too large, the gear displacement design alone cannot meet the corresponding requirements. That is, if the center distance is too small, undercutting will occur, or if the center distance is too large, significant impact will occur during operation. In this case, the bracket can be redesigned to compensate for the problem. The redesign of the bracket means that the rotation center of the bracket remains on the central axis of the large cylindrical gear 4, while the lower part of the bracket plane is eccentrically designed. This means that the bracket can move around the center of the large cylindrical gear 4 with a certain compensation radius, achieving smooth operation without changing its working principle.

[0096] Step 4, the design of the wing translation process, specifically includes:

[0097] During the wing's translational movement, the first clutch 12 disconnects the large cylindrical gear 4 from the slide rail 15 and engages the support shaft of the bracket 3 with the slider 14; the second clutch 13 disengages, and the drive motor 7 drives only the small cylindrical gear 5 to rotate the large cylindrical gear 4. Since the large cylindrical gear 4 meshes with the rack 16, and the rack 16 is fixed to the fuselage 9, the wing 2 achieves forward and backward translational movement under this action. To ensure stability during the movement, the module and pressure angle of the large cylindrical gear 4 and the rack 16 must remain consistent.

[0098] Example 3

[0099] A design method for a worm gear-driven, two-degree-of-freedom wing folding mechanism and aircraft is disclosed. By inputting specific actual design values ​​and setting various parameters of the worm gear set, the design scheme is determined through reverse engineering of the spur gear set. It is worth noting that in this embodiment, all distance calculations are performed in millimeters.

[0100] The specific process of this embodiment is as follows:

[0101] Step 1, Design of worm gear transmission parameters

[0102] When the wing rotates and folds, the second clutch 13 engages, and the drive motor 7 receives an electrical signal, which drives the worm 6 connected to the output shaft of the motor 7 to rotate. Simultaneously, the worm 6 drives the worm wheel 1 to rotate, causing the wing, connected to the worm wheel 1 via key 8, to rotate around the rotation axis 10. The specific design parameters of the worm gear set are as follows:

[0103] Set the transmission ratio of the worm gear set. 1 = 5, take the number of worm gear threads. =6, modulus m1=2.5.

[0104]

[0105]

[0106] The number of teeth on the worm gear can be obtained from the formula. =30, since the center distance of the worm gear is usually taken as 8, 9, 10, 11.2, 12.5, and q is taken as 11.2 in the design process, therefore the center distance is... =51.5.

[0107] Step 2, Design of transmission parameters for spur gear sets

[0108] When the wing rotates and folds, the first clutch 12 selects mode one, which fixes the large cylindrical gear 4 and the slide rail 15. The small cylindrical gear 5, which is fixed to the drive motor 7, begins to rotate under force. Since the large cylindrical gear 4, which meshes with the small cylindrical gear 5, is fixed to the fuselage 9, the small cylindrical gear 5, during its rotation, will drive the interconnected bracket 3, worm gear 1, worm 6, drive motor 7, key 8, wing 2, and second clutch 13 to rotate along the axis centered on the bracket 3. The specific design parameters of the spur gear set are as follows:

[0109] It is important to note that the transmission ratio of the two gear sets must be kept consistent during the design process; therefore, the transmission ratio of the spur gear set should be... 2=5. In GB / T 1357, the preferred module values ​​for spur gears are 0.5, 0.8, 1, 1.25, 1.5, 2... (The module value is not specified in the original text.) 2=1, the pressure angle is 20°, and the minimum number of teeth z3=17 is taken for the small cylindrical gear 5 to avoid undercutting. Therefore:

[0110]

[0111]

[0112]

[0113]

[0114] Step 3: Consider the center distance difference between the worm gear set and the spur gear set and perform compensation design, specifically:

[0115] Considering that the center distance of the worm gear set differs from that of the spur gear set, smooth meshing is achieved by taking into account the center distance variation coefficient:

[0116]

[0117] At this time, as the center distance decreases, the meshing angle decreases accordingly, the gear contact line becomes longer, and the overlap ratio increases, which helps to improve the smoothness of transmission.

[0118] This invention takes the folding process of the left side of the wing as an example. The mechanism on the right side is the same and is axially symmetrical along the fuselage axis, so it is omitted in the analysis. This invention takes the wing folding process as an example, but is not limited to folding. Through a special design of the pressure angle of the worm gear, the wing can be deployed even when the motor is reversed. The implementation process is the reverse of the folding process.

[0119] Step 4, the design of the wing translation process, specifically includes:

[0120] During the wing's translational motion, the first clutch 12 selects mode two, disconnecting the large cylindrical gear 4 from the fuselage 9, while the support shaft of bracket 3 engages with the slider 14; the second clutch 13 disengages, allowing motor 7 to drive only the small cylindrical gear 5, thereby rotating the large cylindrical gear 4. Since the large cylindrical gear 4 meshes with the rack 16, and the rack 16 is fixedly connected to the fuselage 9, the wing 2 achieves forward and backward translational motion under this action. To ensure stability during the motion, the module and pressure angle of the large cylindrical gear 4 and the rack 16 are kept consistent, with a module of 1 and a pressure angle of 20°.

Claims

1. A two-degree-of-freedom wing folding and unfolding mechanism, characterized in that, Includes worm gear (1), bracket (3), large cylindrical gear (4), small cylindrical gear (5), worm (6), drive motor (7), rotating shaft (10), fixed shaft (11), first clutch (12), second clutch (13), slider (14), slide rail (15), rack (16); The wing (2) is fixedly connected to the rotating shaft (10), and the rotating shaft (10) is mounted on the bracket (3) through bearings; The bracket (3) is an integral structure, including a bracket body and a bracket shaft, with the bracket body located at the top and the bracket shaft located at the bottom; the drive motor (7) and the rotating shaft (10) are respectively installed on the bracket body; The worm gear (1) is coaxial with the rotating shaft (10) and connected by a key (8); The output shaft of the drive motor (7), the fixed shaft (11), and the small cylindrical gear (5) are fixedly connected in sequence, and the small cylindrical gear (5) meshes with the large cylindrical gear (4); the drive motor (7) drives the fixed shaft (11) and the small cylindrical gear (5) to rotate; the output shaft of the drive motor (7) is connected to the worm (6) through the second clutch (13), and the second clutch (13) is used to engage and disengage the output shaft of the drive motor (7) and the worm (6); the worm (6) meshes with the worm wheel (1); The slide rail (15) and rack (16) are respectively fixedly installed on the machine body (9), and the slider (14) is installed on the slide rail (15). The slider (14) is used to move along the slide rail (15); the rack (16) meshes with the large cylindrical gear (4), and the large cylindrical gear (4) is connected to the support shaft through the bearing. The large cylindrical gear (4) and the support shaft are coaxial. A first clutch (12) is provided between the large cylindrical gear (4) and the slide rail (15). The first clutch (12) is used to engage or disengage the large cylindrical gear (4) and the slide rail (15), or to engage or disengage the support shaft and the slider (14).

2. The dual-degree-of-freedom wing folding and unfolding mechanism according to claim 1, characterized in that, The worm wheel (1) and worm (6) mesh to form a worm gear set, and the large cylindrical gear (4) and small cylindrical gear (5) mesh to form a spur gear set. The transmission ratio of the worm gear set is the same as that of the spur gear set. The large cylindrical gear (4) and the rack (16) have the same module and the same pressure angle.

3. The dual-degree-of-freedom wing folding and unfolding mechanism according to claim 2, characterized in that, The worm (6) drives the worm wheel (1) to rotate. The worm wheel and worm gear set has a transmission ratio of 5, a module of 2.5, and a center distance of 51.5 mm. The worm (6) has 6 threads, and the worm wheel has 30 teeth. The small cylindrical gear (5) drives the large cylindrical gear (4). The spur gear set has a module of 1, a pressure angle of 20°, and a center distance of 51.5 mm. The small cylindrical gear (5) has 17 teeth and a pitch circle diameter of 17 mm. The large cylindrical gear (4) has 85 teeth and a pitch circle diameter of 85 mm. The center distance variation coefficient is -0.

5.

4. A two-degree-of-freedom winged aircraft, characterized in that, Includes the dual-degree-of-freedom wing folding mechanism as described in claim 1, as well as the wing (2) and the fuselage (9); The wing (2) and fuselage (9) are connected by a two-degree-of-freedom wing folding mechanism; The wing (2) can translate back and forth relative to the fuselage (9), or rotate along the vertical direction of the center of the wing (2) or the wing direction.

5. The dual-degree-of-freedom winged aircraft according to claim 4, characterized in that, When the wings (2) are folded, they are located on both sides of the fuselage (9).

6. A design method for a two-degree-of-freedom wing folding mechanism as described in claim 1, characterized in that, Includes the following steps: Step 1, Design of worm gear transmission parameters: The worm (6) drives the worm wheel (1) to rotate. The transmission parameters of the worm wheel and worm gear set are as follows: ； ； In the above formula, This refers to the transmission ratio of the worm gear set. The number of teeth on the worm gear. The number of worm threads. The center distance of the worm gear set. The module of the worm gear set. This is the worm diameter coefficient; Step 2, Design of transmission parameters for spur gear set: The small cylindrical gear (5) drives the large cylindrical gear (4) to rotate. The transmission parameters of the spur gear set are as follows: ； ； ； ； In the above formula, This refers to the transmission ratio of a spur gear set. The number of teeth for a large cylindrical gear. This refers to the number of teeth on the small cylindrical gear. The center distance of a spur gear set. The module of a spur gear set. The pitch circle diameter of the small cylindrical gear. The pitch circle diameter of the large cylindrical gear; Step 3, Calculate the center distance variation coefficient of the spur gear set: Center distance variation coefficient of spur gear set The expression is: ； In the above formula, The center distance variation coefficient, This refers to the center distance of the worm gear set, i.e., the actual center distance. This refers to the center distance of the spur gear set, i.e., the design center distance. 2 represents the module of the spur gear set; Step 4, Wing translation design: The large cylindrical gear (4) and the rack (16) have the same module and the same pressure angle.

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