Small tandem wing unmanned aerial vehicle folding mechanism

Abstract

The invention discloses a small tandem wing unmanned aerial vehicle folding mechanism which comprises a pair of front wings, a pair of rear wings, a pair of vertical empennages and a fuselage, the front wings and the rear wings are in tandem wing layout on the fuselage after being unfolded, and in a folding state, the pair of front wings rotate backwards around a front rotating shaft to coincide with the back of the fuselage, and the pair of vertical empennages rotate backwards around a rear rotating shaft to coincide with the back of the fuselage. The pair of rear wings rotate forwards around the rear rotating shaft to coincide with the bottom of the fuselage, and the pair of vertical empennages rotate downwards to coincide with the side face of the fuselage. A front spring support is installed on the back of the fuselage and located at the front end of the front rotating shaft, and the pair of front wings is connected with the front spring support through tension springs. A rear spring support is installed at the bottom of the fuselage and located at the rear end of the rear rotating shaft, and the pair of rear wings is connected with the rear spring support through tension springs. The tandem wing layout is adopted, the front wings and the rear wings serve as lift wings, the area of the wings is increased, the size of the unmanned aerial vehicle is reduced, and combat maneuverability is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of aircraft, and in particular relates to a folding mechanism for a small tandem-wing unmanned aerial vehicle. Background Art

[0003] The folding mechanism of existing tandem-wing UAVs is complex. The invention patent with Chinese patent application number 20221167091.3 relates to a tandem-wing linkage folding mechanism for UAVs, which uses an electric slide to drive the rack to move, and the rack drives the gear to rotate, thereby transmitting the torque of the gear to the wing, driving the wing to rotate. This mechanism is complex and bloated, the parts are large and located in the cabin, which greatly occupies the cabin space, and the parts are heavy, which increases the take-off resistance of the UAV, and is not suitable for small tandem-wing UAVs. The invention patent with Chinese patent application number 201811603937.2 relates to a 3D printed folding wing cruise missile. The patent uses magnetic field force as the power to lock the wing, realizing the electrically controlled folding of the wing, but there is no clear description of the folding and unfolding of the vertical tail. Summary of the invention

[0004] In order to solve the technical problems in the prior art such as the complicated folding mechanism of tandem-wing UAV, the large volume and weight of components, and the incomplete folding solution, the present invention provides a folding mechanism for a small tandem-wing UAV.

[0005] The technical solution adopted by the present invention is:

[0006] A small tandem wing unmanned aerial vehicle folding mechanism comprises a pair of front wings (1), a pair of rear wings (2), a pair of vertical tail wings (3), and a fuselage (4). The front wings (1) and the rear wings (2) are arranged in a tandem wing arrangement on the fuselage after being unfolded. The front wings (1) are respectively arranged on both longitudinal sides of the front part of the fuselage (4), the rear wings (2) are respectively arranged on both longitudinal sides of the rear part of the fuselage (4), and the vertical tail wings (3) are respectively arranged on both sides of the rear side of the fuselage (4). After the front wings (1) are folded, they are located above the fuselage (4), and after the rear wings (2) are folded, they are located below the fuselage (4). The vertical tail wings (3) are respectively arranged on both longitudinal sides of the rear part of the fuselage (4). After folding, the two front wings (1) are located on both sides of the rear end of the fuselage (4); characterized in that a front rotating shaft (8) is fixedly provided on the back of the fuselage (4), and a pair of front wings (1) are rotatably connected to the front rotating shaft (8); a rear rotating shaft (17) is fixedly provided on the bottom of the fuselage (4), and a pair of rear wings (2) are rotatably connected to the rear rotating shaft (17); in the folded state, the pair of front wings (1) rotate backwards around the front rotating shaft (8) to overlap with the back of the fuselage (4), the pair of rear wings (2) rotate forwards around the rear rotating shaft (17) to overlap with the bottom of the fuselage (4), and the pair of vertical tail wings (3) rotate downwards to overlap with the side of the fuselage (4);

[0007] A front spring support (7) is installed on the back of the fuselage (4), and the front spring support (7) is located at the front end of the front shaft (8). A pair of front wings (1) are connected to the front spring support (7) via tension springs (5, 6) respectively.

[0008] A rear spring support (16) is installed at the bottom of the fuselage (4), and the rear spring support (16) is located at the rear end of the rear shaft (17). A pair of rear wings (2) are connected to the rear spring support (16) via tension springs (14, 15) respectively.

[0009] Furthermore, a front limiting mechanism (9) is provided at the front end of the front rotating shaft (8); when the front wing (1) is in an unfolded state, the front limiting mechanism (9) contacts the front wing (1); when the front wing (1) is in a folded state, the front limiting mechanism (9) is separated from the front wing (1).

[0010] Furthermore, the front limit mechanism (9) comprises a front limit support, a pair of round shafts (10, 11) and a round shaft mounting frame, wherein the round shaft mounting frame is fixedly mounted on the front limit support, the front limit support is fixedly arranged on the back of the fuselage (4) and is located between the front wing (1) and the front spring support (7), the round shaft mounting frame is provided with a through hole for the round shaft to pass through, one end of the round shaft passes through the through hole, and the other end cooperates with the slot at the front end of the front wing, a retaining ring is arranged on the other end of the round shaft, and a pressure spring is sleeved on the round shaft between the retaining ring and the through hole; when the front wing (1) is in an unfolded state, the other end of the round shaft is clamped in the slot at the front end of the front wing, and the pressure spring is in an extended state at this time; when the front wing (1) is in a folded state, the round shaft withdraws from the slot at the front end of the front wing (1), and the pressure spring is in a compressed state at this time.

[0011] Furthermore, a rear limit mechanism (18) is provided at the rear end of the rear rotating shaft (17); when the rear wing (2) is in an unfolded state, the rear limit mechanism (18) contacts the front wing (2); when the rear wing (2) is in a folded state, the rear limit mechanism (18) is separated from the rear wing (2).

[0012] Furthermore, the rear limit mechanism (18) includes a rear limit support and limit blocks arranged on both sides of the rear limit support, the fixing member of the rear spring support (17) is installed in the rear limit support, and the two ends of the rear spring support (17) are respectively abutted against the inner sides of the limit blocks on both sides; the two tension springs are cross-arranged, one end of the tension spring is connected to the rear spring support (17), and the other end is connected to the rear wing (2).

[0013] Furthermore, one end of a pair of vertical tail wings (3) is connected to the end covers (19, 20) by bolts, respectively, and the end covers (19, 20) are connected to the bushings (21, 22) by bolts, respectively. The bushings (21, 22) are connected to each other, and a long bolt (23) is arranged at the connection between the two. The long bolt (23) is vertically arranged at the connection, and the long bolt (23) is located between the upper positioning column (24) and the lower positioning column (25); a torsion spring (26) is arranged below the long bolt (23), and the middle of the torsion spring (26) is respectively sleeved on the two bushings (21, 22), one end is located below the long bolt (23), and the other end is overlapped under the lower positioning column (25); the two The top of each vertical tail (3) is provided with a through hole, and the two vertical tails (3) are connected by an aluminum rod (27), and the aluminum rod (27) is inserted into the through hole; when the vertical tail (3) is in a folded state, a pair of the vertical tails (3) are in contact with the side of the fuselage (4), and the aluminum rod (27) is located below the front wing (1) and above the back of the fuselage (4). At this time, the long bolt (23) is separated from the upper positioning column (24), and the torsion spring (26) is in a bent state; when the vertical tail (3) is in an unfolded state, the aluminum rod (27) leaves the back of the fuselage (4), the torsion spring (26) is in an extended state, and the long bolt (23) is in contact with the upper positioning column (24).

[0014] Furthermore, one end of a pair of vertical tail wings (3) is provided with a slide groove corresponding to the position of the upper positioning column (24) and the lower positioning column (25), and the upper positioning column (24) and the lower positioning column (25) are fixed to the fuselage (4) by bolts, and the bolts at both ends are respectively clamped in the slide groove.

[0015] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0016] 1. The present invention adopts a tandem wing layout, with front wings and rear wings as lift wings, which increases the wing area, reduces the size of the UAV, and improves combat maneuverability.

[0017] 2. The folding structure of the present invention has a simple principle, readily available materials, clear details, and is easy to use, which can effectively reduce the difficulty of use and deployment. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a structural schematic diagram of the present invention in an unfolded state.

[0019] Figure 2 It is a schematic diagram of the structure of the present invention in a folded state.

[0020] Figure 3 It is an exploded view of the front wing part of the present invention.

[0021] Figure 4 It is a partial exploded view of the front wing part of the present invention.

[0022] Figure 5 It is a top view of the front wing portion of the present invention in the unfolded state.

[0023] Figure 6 It is a top view of the front wing portion of the present invention in a folded state.

[0024] Figure 7 It is a schematic cross-sectional view of the front wing portion of the present invention in the unfolded state.

[0025] Figure 8 It is a partial cross-sectional schematic diagram of the front wing in the folded state of the present invention.

[0026] Fig. 9 It is an exploded view of the rear wing part of the present invention.

[0027] Fig.10 It is a partial exploded view of the rear wing part of the present invention.

[0028] Fig.11 It is a top view of the rear wing portion in the unfolded state of the present invention.

[0029] Fig.12 It is a top view of the rear wing portion of the present invention in a folded state.

[0030] Fig.13 It is an exploded view of the vertical tail part of the present invention.

[0031] Fig.14 It is a schematic diagram of the vertical tail of the present invention in a folded state.

[0032] Fig.15 It is a partial schematic diagram of the vertical tail of the present invention in a folded state.

[0033] Fig.16 It is a schematic diagram of the vertical tail of the present invention in the unfolded state.

[0034] Fig.17 It is a partial schematic diagram of the vertical tail of the present invention in the unfolded state.

[0035] Explanation of the accompanying drawings: 1-front wing, 2-rear wing, 3-vertical tail, 4-fuselage, 5-tension spring, 6-tension spring, 7-front spring support, 8-front rotating shaft, 9-front limit, 10-round shaft, 11-round shaft, 12-compression spring, 13-compression spring, 14-tension spring, 15-tension spring, 16 rear spring support, 17-rear rotating shaft, 18 rear limit, 19 end cover, 20-end cover, 21-bushing, 22-bushing, 23-long bolt, 24-upper positioning column, 25-lower positioning column, 26 torsion spring, 27-aluminum rod. DETAILED DESCRIPTION

[0036] The specific implementation of the embodiment of the present invention is described in detail below in conjunction with the accompanying drawings. It should be understood that the specific implementation described here is only used to illustrate and explain the embodiment of the present invention, and is not used to limit the embodiment of the present invention.

[0037] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments may be combined with each other.

[0038] The present invention will be described in detail below in conjunction with exemplary embodiments with reference to the accompanying drawings.

[0039] refer to Figures 1 to 17 A small tandem wing UAV folding mechanism of the present invention comprises a pair of front wings 1, a pair of rear wings 2, a pair of vertical tail wings 3, and a fuselage 4. The front wings 1 and the rear wings 2 are arranged in a tandem wing layout on the fuselage after being unfolded. The front wings 1 are respectively arranged on both sides of the front longitudinal portion of the fuselage 4, the rear wings 2 are respectively arranged on both sides of the rear longitudinal portion of the fuselage 4, and the vertical tail wings 3 are respectively arranged on both sides of the rear side of the fuselage 4. The front wings 1 are located above the fuselage 4 after being folded, and the rear wings 2 are located below the fuselage 4 after being folded. After being folded, the vertical tail 3 is located on both sides of the rear end of the fuselage 4; a front shaft 8 is fixedly provided on the back of the fuselage 4, and a pair of front wings 1 are rotatably connected to the front shaft 8; a rear shaft 17 is fixedly provided on the bottom of the fuselage 4, and a pair of rear wings 2 are rotatably connected to the rear shaft 17; in the folded state, the pair of front wings 1 rotate backward around the front shaft 8 to coincide with the back of the fuselage 4, the pair of rear wings 2 rotate forward around the rear shaft 17 to coincide with the bottom of the fuselage 4, and the pair of vertical tails 3 rotate downward to coincide with the sides of the fuselage 4.

[0040] A front spring support 7 is installed on the back of the fuselage 4, and the front spring support 7 is located at the front end of the front shaft 8. The pair of front wings 1 are connected to the front spring support 7 through tension springs 5 ​​and 6 respectively;

[0041] A rear spring support 16 is installed at the bottom of the fuselage 4, and the rear spring support 16 is located at the rear end of the rear shaft 17. A pair of rear wings 2 are connected to the rear spring support 16 through tension springs (14, 15).

[0042] Specifically, wings are arranged on the fuselage 4, one in front and one behind, one up and one down, to achieve a sufficiently large wing area to increase lift and improve flight performance. The installation angle of a pair of front wings 1 is greater than the installation angle of a pair of rear wings 2, and the pressure center is located before the neutral point. When the angle of attack increases, the pressure center moves backward to the neutral point, making the tandem wing UAV statically stable.

[0043] Specifically, when the front wing 1 is in the unfolded state, the tension spring 5 and the tension spring 6 respectively provide a certain preload force for the pair of front wings 1, and when in the folded state, the tension spring 5 and the tension spring 6 respectively provide the pair of front wings with tension when changing to the unfolded state.

[0044] Specifically, when the rear wing 2 is in the unfolded state, the tension spring 14 and the tension spring 15 respectively provide a certain preload force for the pair of rear wings 2, and when in the folded state, the tension spring 14 and the tension spring 15 respectively provide a tension force for the pair of rear wings 2 when they are transformed into the unfolded state. In one embodiment, a front limit mechanism 9 is provided at the front end of the front shaft (8), and when the front wing 1 is in the unfolded state, the front limit mechanism 9 contacts the front wing 1; when the front wing 1 is in the folded state, the front limit mechanism 9 is separated from the front wing 1. When the pair of front wings are transformed from the folded state to be perpendicular to the fuselage 4, the front limit mechanism 9 limits the front wings from continuing to rotate to ensure the accuracy when unfolding.

[0045] In one embodiment, the front limit mechanism 9 includes a front limit support, a pair of round shafts 10, 11 and a round shaft mounting frame, the round shaft mounting frame is fixedly mounted on the front limit support, the front limit support is fixedly arranged on the back of the fuselage 4 and is located between the front wing 1 and the front spring support 7, the round shaft mounting frame is provided with a through hole for the round shaft to pass through, one end of the round shaft passes through the through hole, and the other end is used in conjunction with the card slot at the front end of the front wing, a retaining ring is arranged on the other end of the round shaft, and a pressure spring is sleeved on the round shaft between the retaining ring and the through hole; when the front wing 1 is in the unfolded state, the other end of the round shaft is clamped in the card slot at the front end of the front wing, and the pressure spring is in an extended state at this time; when the front wing 1 is in the folded state, the round shaft withdraws from the card slot at the front end of the front wing 1, and the pressure spring is in a compressed state at this time.

[0046] Specifically, when the pair of front wings 1 are unfolded to be perpendicular to the fuselage 4, the circular shafts 10 and 11 in the front limit mechanism contact the slots of the front wings, and the pressure springs 12 and 13 release the pressure to clamp the circular shafts 10 and 11 into the pair of front wings 1, so as to prevent the flight from being unstable due to the sweep of the pair of front wings 1 during the climbing and acceleration process. When the pair of front wings 1 need to be returned to the folded state from the unfolded state, the circular shafts 10 and 11 must be pulled outwards to be disengaged from the slots of the pair of front wings 1, and then the pair of front wings 1 must be rotated backwards.

[0047] In one embodiment, a rear limit mechanism 18 is provided at the rear end of the rear shaft 17. When the rear wing 2 is in the unfolded state, the rear limit mechanism 18 contacts the front wing 2; when the rear wing 2 is in the folded state, the rear limit mechanism 18 is separated from the rear wing 2. When the pair of rear wings 2 is transformed from the folded state to be perpendicular to the fuselage 4, the rear limit 18 limits the pair of rear wings 2 from continuing to rotate to ensure the accuracy during unfolding.

[0048] In one embodiment, the rear limit mechanism 18 includes a rear limit support and limit blocks arranged on both sides of the rear limit support, the fixing member of the rear spring support 17 is installed in the rear limit support, and the two ends of the rear spring support 17 are respectively abutted against the inner sides of the limit blocks on both sides; the two tension springs are cross-arranged, one end of the tension spring is connected to the rear spring support 17, and the other end is connected to the rear wing 2.

[0049] In one embodiment, one end of a pair of vertical tail wings 3 is connected to end covers 19 and 20 respectively by bolts, and the end covers 19 and 20 are connected to bushings 21 and 22 by bolts respectively. The bushings 21 and 22 are connected to each other, and a long bolt 23 is provided at the connection between the two. The long bolt 23 is vertically connected to the connection by bolts, and the long bolt 23 is located between the upper positioning column 24 and the lower positioning column 25; a torsion spring 26 is provided below the long bolt 23, and the middle of the torsion spring 26 is respectively sleeved on the two bushings 21 and 22, one end of which is located below the long bolt 23, and the other end is overlapped on the lower positioning column 25. The top of each of the two vertical tail wings 3 is provided with a through hole, and the two vertical tail wings 3 are connected by an aluminum rod 27, and the aluminum rod 27 is inserted into the through hole; when the vertical tail wings 3 are in a folded state, a pair of the vertical tail wings 3 are in contact with the side of the fuselage 4, and the aluminum rod 27 is located below the front wing 1 and above the back of the fuselage 4. At this time, the long bolt 23 is separated from the upper positioning column 24, and the torsion spring 26 is in a bent state; when the vertical tail wings 3 are in an unfolded state, the aluminum rod 27 leaves the back of the fuselage 4, the torsion spring 26 is in an extended state, and the long bolt 23 is in contact with the upper positioning column 24.

[0050] Specifically, when the vertical tail 3 changes from the deployed state to the folded state, the long bolt 23 in the bushings 21 and 22 rotates downward and drives the torsion spring 26 to rotate, so that the torsion spring 26 has sufficient elastic potential energy. When the vertical tail 3 changes from the folded state to the deployed state, under the action of the elastic potential energy of the torsion spring 26, the torsion spring 26 drives the long bolt 23, and then the long bolt 23 drives the bushings 21 and 22, the bushings 21 and 22 drive the end covers 19 and 20, and the end covers 19 and 20 drive the pair of vertical tails 3 to rotate together, so that the pair of vertical tails 3 are deployed.

[0051] The present invention enhances the consistency of the movement of the pair of vertical tail wings 3 by arranging the aluminum rod 27; in addition, when the tandem-wing UAV changes from a folded state to an unfolded state, in order to prevent the pair of vertical tail wings 3 from unfolding before the pair of front wings 1, resulting in the pair of front wings 1 being unable to unfold, the aluminum rod 27 is constrained under the pair of front wings 1 in a compressed state. If the pair of front wings 1 are not unfolded, the aluminum rod 27 is restricted under the pair of front wings 1 and cannot be unfolded. The pair of vertical tail wings 3 can only be unfolded after the pair of front wings 1 are unfolded.

[0052] In one embodiment, a pair of vertical tail fins 3 are provided with slide grooves at one end corresponding to the positions of the upper positioning column 24 and the lower positioning column 25, respectively. The upper positioning column 24 and the lower positioning column 25 are fixed to the fuselage (4) by bolts, and the bolts at both ends are respectively clamped in the slide grooves. When the vertical tail fin 3 rotates, it does not interfere with the end bolts of the upper and lower positioning columns 24 and 25.

[0053] In the description of the present invention, it is to be understood that the terms “center”, “longitudinal”, “lateral”, “length”, “width”, “thickness”, “up”, “down”, “front”, “back”, “left”, “right”, “vertical”, “horizontal”, “top”, “bottom”, “inside”, “outside”, “clockwise”, “counterclockwise”, “axial”, “radial”, “circumferential”, etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0054] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0055] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral one; it can be a mechanical connection, an electrical connection, or communication with each other; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0056] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0057] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0058] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. A folding mechanism for a small tandem-wing UAV, comprising a pair of front wings (1), a pair of rear wings (2), a pair of vertical tail wings (3), and a fuselage (4); the front wings (1) and the rear wings (2) are arranged in a tandem wing layout on the fuselage after unfolding; the front wings (1) are respectively arranged on both sides of the front longitudinal portion of the fuselage (4); the rear wings (2) are respectively arranged on both sides of the rear longitudinal portion of the fuselage (4); the vertical tail wings (3) are respectively arranged on both sides of the rear side of the fuselage (4); the front wings (1) are located above the fuselage (4) after folding; the rear wings (2) are located below the fuselage (4) after folding; and the vertical tail wings (3) are located on both sides of the tail end of the fuselage (4) after folding; characterized in that: A front rotating shaft (8) is fixedly provided on the back of the fuselage (4), and a pair of front wings (1) are rotatably connected to the front rotating shaft (8); a rear rotating shaft (17) is fixedly provided on the bottom of the fuselage (4), and a pair of rear wings (2) are rotatably connected to the rear rotating shaft (17); in a folded state, the pair of front wings (1) rotate backwards around the front rotating shaft (8) to overlap with the back of the fuselage (4), the pair of rear wings (2) rotate forwards around the rear rotating shaft (17) to overlap with the bottom of the fuselage (4), and the pair of vertical tail wings (3) rotate downwards to overlap with the sides of the fuselage (4); A front spring support (7) is installed on the back of the fuselage (4), and the front spring support (7) is located at the front end of the front shaft (8). A pair of front wings (1) are connected to the front spring support (7) via tension springs (5, 6) respectively. A rear spring support (16) is installed at the bottom of the fuselage (4), and the rear spring support (16) is located at the rear end of the rear shaft (17). A pair of rear wings (2) are connected to the rear spring support (16) via tension springs (14, 15) respectively.

2. A small tandem-wing UAV folding mechanism as claimed in claim 1, characterized in that: A front limiting mechanism (9) is provided at the front end of the front rotating shaft (8); when the front wing (1) is in an unfolded state, the front limiting mechanism (9) contacts the front wing (1); when the front wing (1) is in a folded state, the front limiting mechanism (9) separates from the front wing (1).

3. A small tandem-wing UAV folding mechanism as claimed in claim 2, characterized in that: The front limit mechanism (9) comprises a front limit support, a pair of round shafts (10, 11) and a round shaft mounting frame, wherein the round shaft mounting frame is fixedly mounted on the front limit support, the front limit support is fixedly mounted on the back of the fuselage (4) and is located between the front wing (1) and the front spring support (7), the round shaft mounting frame is provided with a through hole for the round shaft to pass through, one end of the round shaft passes through the through hole, and the other end cooperates with the slot at the front end of the front wing, a retaining ring is arranged on the other end of the round shaft, and a pressure spring is sleeved on the round shaft between the retaining ring and the through hole; when the front wing (1) is in an unfolded state, the other end of the round shaft is clamped in the slot at the front end of the front wing, and the pressure spring is in an extended state at this time; when the front wing (1) is in a folded state, the round shaft exits the slot at the front end of the front wing (1), and the pressure spring is in a compressed state at this time.

4. The folding mechanism of a small tandem-wing UAV as claimed in claim 1, characterized in that: A rear limit mechanism (18) is provided at the rear end of the rear rotating shaft (17); when the rear wing (2) is in an unfolded state, the rear limit mechanism (18) contacts the front wing (2); when the rear wing (2) is in a folded state, the rear limit mechanism (18) is separated from the rear wing (2).

5. A small tandem-wing UAV folding mechanism as claimed in claim 4, characterized in that: The rear limit mechanism (18) comprises a rear limit support and limit blocks arranged on both sides of the rear limit support, the fixing member of the rear spring support (17) is installed in the rear limit support, and the two ends of the rear spring support (17) are respectively abutted against the inner sides of the limit blocks on both sides; the two tension springs are cross-arranged, one end of the tension spring is connected to the rear spring support (17), and the other end is connected to the rear wing (2).

6. The folding mechanism of a small tandem-wing UAV as claimed in claim 1, characterized in that: One end of a pair of vertical tail wings (3) is rotatably connected to the end covers (19, 20) by bolts, respectively. The end covers (19, 20) are bolted to the bushings (21, 22) respectively. The bushings (21, 22) are connected to each other, and a long bolt (23) is arranged at the connection between the two. The long bolt (23) is vertically connected to the connection by bolts, and the long bolt (23) is located between the upper positioning column (24) and the lower positioning column (25); a torsion spring (26) is arranged below the long bolt (23), and the middle of the torsion spring (26) is respectively sleeved on the two bushings (21, 22), one end of which is located below the long bolt (23) and the other end of which is overlapped below the lower positioning column (25); the two The top of each vertical tail (3) is provided with a through hole, and the two vertical tails (3) are connected by an aluminum rod (27), and the aluminum rod (27) is inserted into the through hole; when the vertical tail (3) is in a folded state, a pair of the vertical tails (3) are in contact with the side of the fuselage (4), and the aluminum rod (27) is located below the front wing (1) and above the back of the fuselage (4). At this time, the long bolt (23) is separated from the upper positioning column (24), and the torsion spring (26) is in a bent state; when the vertical tail (3) is in an unfolded state, the aluminum rod (27) leaves the back of the fuselage (4), the torsion spring (26) is in an extended state, and the long bolt (23) is in contact with the upper positioning column (24).

7. A small tandem-wing UAV folding mechanism as claimed in claim 6, characterized in that: One end of a pair of vertical tail wings (3) is provided with a slide groove at a position corresponding to an upper positioning column (24) and a lower positioning column (25), and the upper positioning column (24) and the lower positioning column (25) are fixed to the fuselage (4) by bolts, and the bolts at both ends are respectively clamped in the slide groove.

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