Blade folding mechanism and helicopter

Abstract

This application provides a rotor blade folding mechanism and a helicopter. The rotor blade folding mechanism includes a rotor clamp and a rotor blade. The rotor blade is rotatably connected to the rotor clamp and can move relative to the rotor clamp between a folded position and an unfolded position. It also includes a limiting component configured to restrict the rotation of the rotor blade relative to the rotor clamp in the unfolded position. The limiting component includes a limiting pin, a pendulum, a limiting groove, and an elastic element. The limiting pin is inserted and rotatably passed through the rotor clamp and the rotor blade. The pendulum is eccentrically connected to one end of the limiting pin. The bottom of the pendulum forms a groove structure. The limiting groove is formed on the rotor clamp on the same side as the pendulum. The limiting groove is a U-shaped groove with its opening opposite to the pendulum. The elastic element protrudes from the rotor clamp located between the limiting pin and the limiting groove. When the rotor blade is in the unfolded position relative to the rotor clamp, the limiting pin passes through the rotor clamp and the rotor blade. The end of the pendulum away from the limiting pin is engaged with the limiting groove, and the elastic element abuts against the groove structure of the pendulum.

Description

Technical Field

[0001] This application relates to the field of unmanned aerial vehicle (UAV) technology, and in particular to a propeller folding mechanism and a helicopter. Background Technology

[0002] Currently, existing helicopter rotor blade folding mechanisms require manual removal of either a quick-release pin or a bolt connecting the rotor blades during the folding process, followed by manual folding of the blades. While widely used, this type of rotor blade folding mechanism suffers from several problems: 1) The quick-release pin has a complex structure and high manufacturing costs, increasing the overall production cost of the rotor blade folding mechanism; 2) The quick-release pin is hollow, resulting in low structural strength and a short service life; 3) The bolts require the use of safety pins, making bolt installation and removal inconvenient. Summary of the Invention

[0003] The purpose of this application is to provide a rotor blade folding mechanism and a helicopter to solve the problems existing in the prior art rotor blade folding mechanisms. To achieve the above objective, the specific technical solution is as follows:

[0004] An embodiment of the first aspect of this application provides a blade folding mechanism, including a blade clamp and a blade, wherein the blade is rotatably connected to the blade clamp and the blade is movable relative to the blade clamp between a folded position and an unfolded position.

[0005] It also includes a limiting component configured to restrict the rotation of the blade relative to the propeller clamp in the deployed position. The limiting component includes a limiting pin, a pendulum, a limiting groove, and an elastic element. The limiting pin is inserted and rotatably passed through the propeller clamp and the blade. The pendulum is eccentrically connected to one end of the limiting pin and has a groove structure formed at the bottom of the pendulum. The limiting groove is formed on the propeller clamp on the same side as the pendulum and is a U-shaped groove with its opening opposite to the pendulum. The elastic element protrudes from the propeller clamp located between the limiting pin and the limiting groove.

[0006] When the blade is in the unfolded position relative to the blade clamp, the limiting pin passes through the blade and the blade, the end of the pendulum away from the limiting pin is engaged in the limiting groove, and the top of the elastic element abuts against the groove structure of the pendulum.

[0007] The blade folding mechanism of this application embodiment has a blade rotatably connected to a blade clamp, and the blade can move relative to the blade clamp between a folded position and an unfolded position. The blade folding mechanism also includes a limiting component that restricts the rotation of the blade relative to the blade clamp in the unfolded position. Specifically, the limiting component includes a limiting pin, a pendulum, a limiting groove, and an elastic element. When the blade is in the unfolded position relative to the blade clamp, the limiting pin is inserted through the blade clamp and the blade. The pendulum is eccentrically connected to one end of the limiting pin, and then the pendulum is driven to rotate towards the limiting groove. Since the limiting pin can rotate relative to the blade clamp and the blade, and the pendulum is connected to one end of the limiting pin, the pendulum can drive the limiting pin to rotate synchronously relative to the blade clamp and the blade. When the pendulum rotates to the limiting groove, the end of the pendulum away from the limiting pin extends into the limiting groove, and the elastic element is compressed, thereby applying a reverse force to the pendulum, increasing the friction between the pendulum and the limiting groove. Simultaneously, the top of the elastic element abuts against the groove structure of the pendulum. This restricts the pendulum's rotation around the limiting pin, thus providing a mechanical locking effect. The pendulum engages with the limiting groove, restricting the axial movement of the limiting pin relative to the propeller clamp and blade. This prevents the limiting pin from being pulled out of the propeller clamp and blade, thereby restricting the blade's rotation relative to the propeller clamp and keeping the blade in the unfolded position relative to the propeller clamp. When folding the blade is required, external force is applied to overcome the friction between the pendulum and the elastic element, rotating the pendulum so that the end of the pendulum furthest from the limiting pin slides out of the limiting groove. Then, the limiting pin passing through the propeller clamp and blade is pulled out, releasing the limiting component's restriction on the blade's rotation relative to the propeller clamp. The blade then rotates relative to the propeller clamp to the folding position, thus completing the blade folding. In summary, the entire blade folding mechanism restricts or unlocks the insertion and removal movement of the limit pin relative to the blade clip and blade by driving the pendulum to extend into or slide out of the limit groove at the end furthest from the limit pin. This, in turn, restricts or unlocks the rotation of the blade relative to the blade clip, allowing the blade to remain in the unfolded position relative to the blade clip, or to rotate to the folded position relative to the blade clip. Compared with existing blade folding mechanisms, this mechanism has advantages such as simple structure, reliability, easy disassembly, and low manufacturing cost, which can greatly reduce the manufacturing cost of helicopters.

[0008] In addition, a blade folding mechanism according to an embodiment of this application may also have the following additional technical features:

[0009] In some embodiments of this application, a first through hole and a second through hole are respectively provided on the propeller clamp and the propeller blade. The first through hole and the second through hole are coaxially distributed, and the limiting pin is clearance-fitted into the first through hole and the second through hole. A bushing is provided in the first through hole on the side of the propeller clamp near the pendulum. The bushing is interference-fitted with the first through hole and clearance-fitted with the limiting pin. A limiting boss is provided on the outer wall of the limiting pin located below the pendulum. A stepped structure is provided on the inner wall of the first through hole on the side of the propeller clamp near the pendulum. The stepped structure is adapted to the limiting boss.

[0010] In some embodiments of this application, a limiting retaining ring is also included. The pendulum has an eccentrically formed third through hole. One end of the limiting pin passes through the third through hole. A snap-fit ​​assembly is provided between the limiting pin and the third through hole. The snap-fit ​​assembly includes a protruding structure and a groove adapted to the protruding structure. A first groove is formed on the outer wall of the limiting pin located directly above the pendulum. The limiting retaining ring is placed on the top of the pendulum and snapped into the first groove.

[0011] In some embodiments of this application, a boss structure is provided on the propeller clamp, the boss structure is distributed on the same side as the pendulum, and a slot structure is opened on the side of the boss structure near the pendulum.

[0012] In some embodiments of this application, the elastic element includes a column, a sphere, and a spring. A semi-enclosed cavity is formed inside the column. The sphere protrudes from the open end of the semi-enclosed cavity. The spring is disposed inside the semi-enclosed cavity, with one end connected to the sphere and the other end connected to the bottom of the semi-enclosed cavity. The column of the elastic element is movably disposed within the propeller clamp located between the limiting pin and the limiting groove. The sphere of the elastic element protrudes from the surface of the propeller clamp, and the groove structure is a second groove adapted to the sphere.

[0013] In some embodiments of this application, the outer wall of the column is provided with external threads, and a threaded blind hole is opened on the paddle clamp, and the column is screwed into the threaded blind hole.

[0014] In some embodiments of this application, the pendulum has a toggle groove structure on the side away from the elastic element; a third groove is provided at one end of the limiting pin.

[0015] In some embodiments of this application, a first notch is provided on the limiting ring, protrusions are provided at both ends of the first notch, and a plurality of second notches are provided at intervals on the inner periphery of the limiting ring.

[0016] In some embodiments of this application, the blade is rotatably connected to the blade clamp via a rotating mechanism, the rotating mechanism including a bolt and a nut, and a fourth through hole and a fifth through hole are respectively opened on the blade clamp and the blade. The fourth through hole and the fifth through hole are coaxially arranged, and the bolt passes through the fourth through hole and the fifth through hole in sequence and is connected to the nut.

[0017] An embodiment of the second aspect of this application provides a helicopter including a blade folding mechanism according to any of the above embodiments.

[0018] According to the embodiments of the present application, the rotor blade folding mechanism drives the end of the pendulum away from the limiting pin to extend into or slide out of the limiting groove, thereby limiting or unlocking the insertion and removal movement of the limiting pin relative to the rotor clip and the rotor blade, thereby limiting or unlocking the rotation of the rotor blade relative to the rotor clip, so that the rotor blade can remain in the unfolded position relative to the rotor clip, or the rotor blade can rotate to the folded position relative to the rotor clip. Compared with the rotor blade folding mechanism in the prior art, it has the advantages of simple structure, reliability, convenient disassembly, and low manufacturing cost, which can greatly reduce the manufacturing cost of helicopters. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other embodiments can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a schematic diagram of the blade folding mechanism in an embodiment of this application;

[0021] Figure 2 This is a cross-sectional schematic diagram of the blade folding mechanism in an embodiment of this application;

[0022] Figure 3 for Figure 2 A partial schematic diagram;

[0023] Figure 4 This is a schematic diagram of the blade folding mechanism from the upper right perspective in an embodiment of this application.

[0024] Figure 5 This is a schematic diagram of the limiting pin of the blade folding mechanism in the embodiments of this application;

[0025] Figure 6 This is a schematic diagram of the pendulum structure of the blade folding mechanism in the embodiments of this application;

[0026] Figure 7 This is a schematic diagram of the back of the pendulum of the blade folding mechanism in the embodiments of this application. Detailed Implementation

[0027] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other embodiments can be obtained based on these drawings.

[0028] For ease of description, spatial relative terms may be used in the text to describe the relationship of one element or feature relative to another element or feature as shown in the figure. These relative terms include, for example, "inside," "outside," "middle," "outer," "below," "below," "above," "upper," etc. Such spatial relative terms are intended to include different orientations of the device in use or operation, other than those depicted in the figure.

[0029] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art based on this application are within the scope of protection of this application.

[0030] like Figure 1 , Figure 2 As shown, an embodiment of the first aspect of this application provides a blade folding mechanism 100. The blade folding mechanism 100 includes a blade clamp 110 and a blade 120. The blade 120 is rotatably connected to the blade clamp 110 and is movable relative to the blade clamp 110 between a folded position and an unfolded position. It also includes a limiting component 130 configured to restrict the rotation of the blade 120 relative to the blade clamp 110 in the unfolded position. The limiting component 130 includes a limiting pin 131, a pendulum 132, a limiting groove 133, and an elastic element 134. The limiting pin 131 is inserted and rotatably disposed on the blade clamp 110 and the blade 120. The pendulum 132 is eccentrically connected to the limiting pin 131. At one end of 1, the bottom of the pendulum 132 forms a groove structure, and the limiting groove 133 is formed on the same side as the pendulum 132 on the propeller clamp 110. The limiting groove 133 is a U-shaped groove with the opening opposite to the pendulum 132. The elastic element 134 protrudes and is set on the propeller clamp 110 located between the limiting pin 131 and the limiting groove 133. When the propeller blade 120 is in the unfolded position relative to the propeller clamp 110, the limiting pin 131 passes through the propeller clamp 110 and the propeller blade 120, the end of the pendulum 132 away from the limiting pin 131 is engaged in the limiting groove 133, and the top of the elastic element 134 abuts against the groove structure of the pendulum 132.

[0031] The blade folding mechanism 100 of this application embodiment has a blade 120 rotatably connected to a blade clamp 110, and the blade 120 can move relative to the blade clamp 110 between a folded position and an unfolded position. The blade folding mechanism 100 also includes a limiting component 130 that restricts the rotation of the blade 120 relative to the blade clamp 110 in the unfolded position. Specifically, the limiting component 130 includes a limiting pin 131, a pendulum 132, a limiting groove 133, and an elastic element 134. When the blade 120 is in the unfolded position relative to the blade clamp 110, the limiting pin 131 is inserted through the blade clamp 110 and the blade 120. The pendulum 132 is eccentrically connected to one end of the limiting pin 131, and then the pendulum 132 is driven to rotate towards the limiting groove 133. Since the limiting pin 131 can rotate relative to the blade clamp 110 and the blade 120, the pendulum 132 is connected... Connected to one end of the limiting pin 131, the pendulum 132 can drive the limiting pin 131 to rotate synchronously relative to the propeller clamp 110 and the propeller blade 120. When the pendulum 132 rotates to the limiting groove 133, the end of the pendulum 132 away from the limiting pin 131 extends into the limiting groove 133. The elastic element 134 is compressed, thereby applying a reverse force to the pendulum 132, increasing the friction between the pendulum 132 and the limiting groove 133. At the same time, the top of the elastic element 134 abuts against the pendulum 132. Within the groove structure, the pendulum 132 is restricted from rotating around the limiting pin 131, thereby achieving a mechanical locking effect. This causes the pendulum 132 to engage with the limiting groove 133, thus restricting the axial movement of the limiting pin 131 relative to the propeller clamp 110 and the propeller blade 120. This prevents the limiting pin 131 from being pulled out of the propeller clamp 110 and the propeller blade 120, thereby restricting the rotation of the propeller blade 120 relative to the propeller clamp 110, keeping the propeller blade 120 in the deployed position relative to the propeller clamp 110. When needed... When folding the blade 120, an external force is applied to overcome the friction between the pendulum 132 and the elastic element 134, and the pendulum 132 is rotated so that the end of the pendulum 132 away from the limiting pin 131 slides out of the limiting groove 133. Then the limiting pin 131 passing through the blade 120 is pulled out, thereby releasing the limitation of the limiting component 130 on the rotation of the blade 120 relative to the blade clamp 110. The blade 120 rotates relative to the blade clamp 110 to the folding position, thereby completing the folding of the blade 120. In summary, the entire blade folding mechanism 100 drives the pendulum 132 to extend into or slide out of the limiting groove 133 at one end away from the limiting pin 131, thereby limiting or unlocking the insertion and removal movement of the limiting pin 131 relative to the blade clip 110 and the blade 120, and thus limiting or unlocking the rotation of the blade 120 relative to the blade clip 110. This allows the blade 120 to remain in the unfolded position relative to the blade clip 110, or the blade 120 to rotate to the folded position relative to the blade clip 110. Compared with the blade folding mechanism in the prior art, it has the advantages of simple structure, reliability, convenient disassembly, and low manufacturing cost, which can greatly reduce the manufacturing cost of helicopters.

[0032] In some embodiments of this application, such as Figure 2 As shown, a first through hole 111 and a second through hole 121 are respectively provided on the propeller clamp 110 and the propeller blade 120. The first through hole 111 and the second through hole 121 are coaxially distributed. The limiting pin 131 is fitted into the first through hole 111 and the second through hole 121 with clearance. Thus, the limiting pin 131 is inserted and rotated through the propeller clamp 110 and the propeller blade 120.

[0033] Furthermore, such as Figure 3 As shown, a bushing 140 is provided in the first through hole 111 on the side of the propeller clamp 110 near the pendulum 132. The bushing 140 and the first through hole 111 are interference-fitted, and the bushing 140 and the limiting pin 131 are clearance-fitted. Since the insertion and removal of the limiting pin 131 will cause some wear to the propeller clamp 120, by providing a bushing 140 in the first through hole 111 of the propeller clamp 110, the limiting pin 131 can only contact the bushing 140. In this way, even if wear occurs, only the bushing 140 will wear, and only the bushing 140 needs to be replaced in time, thereby effectively avoiding wear of the propeller clamp 110.

[0034] Furthermore, the bushing 140 can be made of high-hardness, wear-resistant beryllium bronze, which can increase the wear resistance of the bushing 140 and thus extend its service life.

[0035] In some embodiments of this application, such as Figures 3 to 6 As shown, the blade folding mechanism 100 also includes a limiting retaining ring 150. A third through hole 1321 is eccentrically formed on the pendulum 132. One end of the limiting pin 131 passes through the third through hole 1321. A snap-fit ​​assembly is provided between the limiting pin 131 and the third through hole 1321. A first groove 1311 is formed on the outer wall of the limiting pin 131 located directly above the pendulum 132. The limiting retaining ring 150 is placed on the top of the pendulum 132 and snapped into the first groove 1311. Thus, the limiting retaining ring 150 restricts the axial movement of the pendulum 132 along the limiting pin 131. Furthermore, because the snap-fit ​​assembly is provided between the limiting pin 131 and the third through hole 1321, relative rotation between the limiting pin 131 and the pendulum 132 is prevented; that is, when the pendulum 132 rotates, it can drive the limiting pin 131 to rotate together.

[0036] In some embodiments of this application, the snap-fit ​​assembly includes a protrusion structure 161 and a groove 162 adapted to the protrusion structure. Specifically, as Figure 4 , Figure 6As shown, the protrusion 161 is disposed on the inner wall of the third through hole 1321, and the groove 162 is axially opened on one end of the limiting pin 131, extending from one end of the limiting pin 131 to below the first groove 1311; of course, the positions of the protrusion 161 and the groove 162 can also be interchanged, that is, the protrusion 161 is disposed on one end of the limiting pin 131, and the protrusion 161 extends from one end of the limiting pin 131 to below the first groove 1311, and the groove 162 is axially opened on the side wall of the third through hole 1321. Therefore, the relative rotation of the limiting pin 131 and the pendulum 132 can be prevented by the cooperation of the protrusion structure 161 and the groove 162, so that the pendulum 132 can drive the limiting pin 131 to rotate synchronously. At the same time, the cooperation of the protrusion structure 161 and the groove 162 does not restrict the axial movement between the pendulum 132 and the limiting pin 131, thus facilitating the installation of the limiting pin 131 and the pendulum 132.

[0037] In some embodiments of this application, such as Figure 5 As shown, a limiting boss 1312 is provided on the outer wall of the limiting pin 131 located below the pendulum 132. A stepped structure is provided on the inner wall of the first through hole 111 on the side of the paddle clamp 110 near the pendulum 132. The stepped structure is adapted to the limiting boss 1312, so that the limiting pin 131 will not continue to move downward when it is in clearance fit within the first through hole 111 and the second through hole 121, thereby realizing the axial limiting of the limiting pin 131 and facilitating the installation of the limiting pin 131.

[0038] In some embodiments of this application, such as Figure 3 , Figure 4 As shown, a boss structure 112 is provided on the propeller clamp 110. The boss structure 112 and the pendulum 132 are distributed on the same side. A slot structure is opened on the side of the boss structure 112 near the pendulum 132, which is the limiting slot 133.

[0039] In some embodiments of this application, such as Figure 3 As shown, the elastic element 134 includes a column 1341, a ball 1342, and a spring 1343. A semi-enclosed cavity is formed inside the column 1341. The ball 1342 protrudes from the open end of the semi-enclosed cavity. The spring 1343 is disposed within the semi-enclosed cavity. One end of the spring 1343 is connected to the ball 1342, and the other end is connected to the bottom of the semi-enclosed cavity. The column 1341 of the elastic element 134 is movably disposed within the paddle clamp 110 located between the limiting pin 131 and the limiting groove 133. The ball 1342 of the elastic element 134 protrudes from the surface of the paddle clamp 110. Figure 7As shown, the groove structure is a second groove 1322 that is adapted to the sphere 1342. Therefore, during the process of driving the pendulum 132 to rotate into the limiting groove 133, the pendulum 132 continuously presses down on the ball 1342 of the elastic element 134. The end of the pendulum 132 away from the limiting pin 131 gradually extends into the limiting groove 133. When the pendulum 132 rotates to the position, the ball 1342 of the elastic element 134 engages in the second groove 1322 of the pendulum 132. Under the action of the preload of the spring 1343, the ball 1342 restricts the rotation of the pendulum 132 around the limiting pin 131, so that the end of the pendulum 132 away from the limiting pin 131 is engaged in the limiting groove 133, thereby restricting the axial movement of the limiting pin 110 relative to the propeller clamp 110 and the propeller blade 120, so that the limiting pin 110 cannot be pulled out from the propeller clamp 110 and the propeller blade 120, thereby restricting the rotation of the propeller blade 120 relative to the propeller clamp 110. In addition, the sphere 1342 fits into the second groove 1322, which can limit the back-and-forth and left-and-right swaying of the pendulum 132, thereby improving the reliability of the blade 120 in the deployed position.

[0040] In some embodiments of this application, the outer wall of the column 1341 is provided with external threads, and a threaded blind hole is opened on the paddle clamp 110. The column 1341 is screwed into the threaded blind hole, which facilitates the installation of the elastic element 134.

[0041] In some embodiments of this application, such as Figure 6 As shown, the side of the pendulum 132 away from the elastic element 134 is provided with a toggle groove structure 1323, which allows the operator to easily toggle the pendulum 132 to rotate.

[0042] In some embodiments of this application, such as Figure 5 As shown, a third groove 1313 is provided at one end of the limiting pin 131. The operator can easily pinch the limiting pin 131 through the third groove 1313, thereby facilitating the insertion and removal of the limiting pin 131.

[0043] In some embodiments of this application, a first notch is provided on the retaining ring 150, and protrusions are provided at both ends of the first notch. This allows the retaining ring 150 to be easily engaged in the first groove 1311. At the same time, the protrusions at both ends of the first notch are in a slightly expanded state after the retaining ring 150 is engaged in the first groove 1311, which makes the retaining ring 150 more securely engaged. Furthermore, multiple second notches are provided at intervals on the inner periphery of the retaining ring 150, which increases the elasticity of the retaining ring 150.

[0044] In some embodiments of this application, the blade 120 is rotatably connected to the blade clamp 110 via a rotating mechanism. Specifically, the rotating mechanism includes a bolt and a nut. A fourth through hole and a fifth through hole are respectively opened on the blade clamp 110 and the blade 120. The fourth through hole and the fifth through hole are coaxially arranged. The bolt passes through the fourth through hole and the fifth through hole in sequence and is connected to the nut, thereby rotatably connecting the blade 10 to the blade clamp 20.

[0045] The second aspect of this application provides a helicopter including the blade folding mechanism 100 of any of the above embodiments. The blade folding mechanism 100 of any of the above embodiments, by driving the end of the pendulum 132 away from the limiting pin 131 to extend into or slide out of the limiting groove 133, restricts or unlocks the insertion and removal movement of the limiting pin 131 relative to the rotor clamp 110 and the blade 120, thereby restricting or unlocking the rotation of the blade 120 relative to the rotor clamp 110. This allows the blade 120 to remain in an unfolded position relative to the rotor clamp 110, or the blade 120 to rotate to a folded position relative to the rotor clamp 110. Compared to blade folding mechanisms in the prior art, this has advantages such as simple structure, reliability, easy disassembly, and low manufacturing cost, which can greatly reduce the manufacturing cost of helicopters.

[0046] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0047] The various embodiments in this specification are described in a related manner. Similar or identical parts between embodiments can be referred to mutually. Each embodiment focuses on describing the differences from other embodiments. The above descriptions are merely preferred embodiments of this application and are not intended to limit the scope of protection of this application. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application are included within the scope of protection of this application.

Claims

1. A blade folding mechanism, characterized in that, The device includes a propeller clamp and a propeller blade, the propeller blade being rotatably connected to the propeller clamp and movable relative to the propeller clamp between a folded position and an unfolded position. It also includes a limiting assembly configured to restrict the rotation of the propeller blade relative to the propeller clamp in the unfolded position. The limiting assembly includes a limiting pin, a pendulum, a limiting groove, and an elastic element. The limiting pin is inserted and rotatably passed through the propeller clamp and the propeller blade. The pendulum is eccentrically connected to one end of the limiting pin, and a groove structure is formed at the bottom of the pendulum. The limiting groove is formed on the propeller clamp on the same side as the pendulum, and the limiting groove is a U-shaped groove with its opening opposite to the pendulum. The elastic element protrudes from the propeller clamp located between the limiting pin and the limiting groove. When the propeller blade is in the unfolded position relative to the propeller clamp, the limiting pin passes through the propeller clamp and the propeller blade, the end of the pendulum away from the limiting pin is engaged in the limiting groove, and the top of the elastic element abuts against the groove structure of the pendulum. A boss structure is provided on the propeller clamp. The boss structure is distributed on the same side as the pendulum. A slot structure is opened on the side of the boss structure near the pendulum, which is the limiting slot. The elastic element includes a column, a sphere, and a spring. The column has a semi-closed cavity, and the sphere protrudes from the open end of the semi-closed cavity. The spring is disposed within the semi-closed cavity, with one end connected to the sphere and the other end connected to the bottom of the semi-closed cavity. The column of the elastic element is movably disposed within the paddle clamp located between the limiting pin and the limiting groove. The sphere of the elastic element protrudes from the surface of the paddle clamp, and the groove structure is a second groove adapted to the sphere. When the pendulum rotates to its position, the ball engages with the second groove, which can limit the pendulum's forward, backward, left, and right swaying, thereby improving the reliability of the blade in the deployed position.

2. The blade folding mechanism as described in claim 1, characterized in that: A first through hole and a second through hole are respectively provided on the propeller clamp and the propeller blade. The first through hole and the second through hole are coaxially distributed. The limiting pin is clearance-fitted into the first through hole and the second through hole. A bushing is provided in the first through hole on the side of the propeller clamp near the pendulum. The bushing is interference-fitted with the first through hole and clearance-fitted with the limiting pin. A limiting boss is provided on the outer wall of the limiting pin located below the pendulum. A stepped structure is provided on the inner wall of the first through hole on the side of the propeller clamp near the pendulum. The stepped structure is adapted to the limiting boss.

3. The blade folding mechanism as described in claim 1, characterized in that: It also includes a limiting retaining ring. The pendulum has an eccentrically formed third through hole. One end of the limiting pin passes through the third through hole. A snap-fit ​​assembly is provided between the limiting pin and the third through hole. The snap-fit ​​assembly includes a protruding structure and a groove adapted to the protruding structure. A first groove is formed on the outer wall of the limiting pin located directly above the pendulum. The limiting retaining ring is placed on the top of the pendulum and snapped into the first groove.

4. The blade folding mechanism as described in claim 1, characterized in that: The outer wall of the column is provided with external threads, and a threaded blind hole is opened on the paddle clamp, and the column is screwed into the threaded blind hole.

5. The blade folding mechanism as described in claim 1, characterized in that: The pendulum has a paving groove structure on the side away from the elastic element; a third groove is provided at one end of the limiting pin.

6. The blade folding mechanism as described in claim 3, characterized in that: A first notch is made on the limiting ring, and protrusions are provided at both ends of the first notch. Multiple second notches are provided at intervals on the inner periphery of the limiting ring.

7. The blade folding mechanism as described in claim 1, characterized in that: The blade is rotatably connected to the blade clamp via a rotating mechanism, which includes a bolt and a nut. A fourth through hole and a fifth through hole are respectively opened on the blade clamp and the blade. The fourth through hole and the fifth through hole are coaxially arranged. The bolt passes through the fourth through hole and the fifth through hole in sequence and is connected to the nut.

8. A helicopter, characterized in that: Includes the blade folding mechanism according to any one of claims 1 to 7.

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