Folding propeller mechanism for aircraft and aircraft

Abstract

The present application discloses a foldable propeller mechanism for an aircraft and an aircraft. The foldable propeller mechanism for an aircraft includes a rotating shaft, a driving member, a first propeller, and a second propeller; the driving member is connected to one end of the rotating shaft; the first propeller includes a first hub and a first blade connected to each other, the first hub being fixedly connected to the rotating shaft, a thrust groove being provided on the side of the first hub facing away from the driving member, the bottom of the thrust groove having a first thrust surface arranged at an angle; the second propeller includes a second hub and a second blade connected to each other, the second hub being movably sleeved on the rotating shaft and located on the side of the first hub facing away from the driving member, a thrust block protruding from the side of the second hub facing the first hub and extending into the thrust groove, the thrust block and the thrust groove cooperating to enable the second blade to be in a folded state or an unfolded state relative to the first blade. The above-mentioned foldable propeller mechanism for an aircraft reduces the resistance of the aircraft during flight and improves the flight performance of the aircraft.

Description

Technical Field

[0001] The present application relates to the technical field of aircraft propulsion devices, and in particular to an aircraft foldable propeller mechanism and an aircraft. Background Art

[0002] Urban air mobility aircraft are divided into multiple configurations such as full-tilt, semi-tilt and compound according to whether the power system is reused during vertical take-off and landing and fixed-wing flight.

[0003] A semi-tilting configuration reuses some of the power system during vertical takeoff and landing (VTOL) and fixed-wing flight through tilting. This means that one portion of the power system (the hovering power system) remains fixed, providing only upward lift, while the remaining power system can tilt around its axis, changing the direction of the propeller disc axis to provide upward lift during vertical takeoff and forward thrust / pull during flight. A combined configuration uses completely independent power systems for vertical takeoff and landing and flight, each comprised of separate hardware.

[0004] However, whether it is a semi-tilt configuration or a compound configuration, the hovering power system not only does not provide lift during the fixed-wing flight phase, but also generates a certain amount of resistance, increasing the power required for level flight, thereby generating huge flight resistance during the flight of the aircraft, which is not conducive to the flight performance of the aircraft. Summary of the Invention

[0005] In view of the above, it is necessary to propose a foldable propeller mechanism for an aircraft and an aircraft to reduce the resistance of the aircraft during flight and improve the flight performance of the aircraft.

[0006] The embodiment of the present application provides a foldable propeller mechanism for an aircraft, comprising a rotating shaft, a driving member, a first propeller and a second propeller; the driving member is connected to one end of the rotating shaft for driving the rotating shaft to rotate; the first propeller comprises a first hub and a first blade connected thereto, the first hub is fixedly connected to the rotating shaft, an arc-shaped thrust groove is provided on the side of the first hub facing away from the driving member, and the bottom of the thrust groove has a first thrust surface arranged obliquely; the second propeller comprises a second hub and a second blade connected thereto, the second hub is movably sleeved on the rotating shaft and located behind the first hub A thrust block extending into the thrust groove is protruded from the second hub on a side away from the driving member and facing the first hub. The thrust block and the thrust groove cooperate to enable the second blade to be in a folded state or an unfolded state relative to the first blade. In the folded state, the circumferential phase difference between the second blade and the first blade is zero. In the unfolded state, the circumferential phase difference between the second blade and the first blade is a preset value. The first thrust surface is used to abut against the thrust block when the second blade switches between the folded state and the unfolded state.

[0007] In some embodiments, the aircraft folding propeller mechanism also includes a thrust elastic member, which is sleeved on the rotating shaft and located on the side of the second hub away from the first hub. One end of the thrust elastic member is connected to the rotating shaft, and the other end of the thrust elastic member is transmission-connected to the second hub. The thrust elastic member is used to apply pressure to the second hub.

[0008] In some embodiments, the aircraft foldable propeller mechanism further includes a sliding bearing, which is sleeved on the rotating shaft and inserted into the second hub, and one end of the thrust elastic member close to the second hub abuts against the sliding bearing.

[0009] In some embodiments, a stop ridge is provided on one end of the rotating shaft away from the driving member along the circumference of the rotating shaft, and an end of the thrust elastic member away from the second hub abuts against the stop ridge.

[0010] In some embodiments, the aircraft folding propeller mechanism also includes a limit assembly, the limit assembly includes a limit base, the limit base is arranged on the rotating shaft and is located on the side of the second hub away from the first hub, the limit base is used to limit the distance of the second hub away from the first hub, and is used to transfer the lift generated by the second blade to the rotating shaft.

[0011] In some embodiments, an arc-shaped guide groove is provided on the side of the second hub facing away from the first hub, the guide groove is concentric with the rotating shaft, the bottom of the guide groove has an abutment slope, and a limiting hole is provided at the end of the abutment slope away from the first hub; the limiting assembly also includes a limiting elastic part and a limiting part, the limiting part is slidably inserted in the limiting base and arranged opposite to the guide groove, the limiting elastic part is arranged in the limiting base, and the two ends of the limiting elastic part are respectively connected to the limiting base and the limiting part, and the limiting elastic part is used to drive the limiting part to be inserted into the limiting hole when the second blade is in the expanded state.

[0012] In some embodiments, the side of the second hub facing the limit base and the side of the limit base facing the second hub respectively have a matching first friction surface and a second friction surface; or, the side of the second hub facing the limit base and the side of the limit base facing the second hub are respectively provided with a matching mortise and tenon structure.

[0013] In some embodiments, the thrust block has a second thrust surface on a side facing the first thrust surface, which is in surface contact with the first thrust surface.

[0014] In some embodiments, the aircraft folding propeller mechanism also includes a first fairing and a second fairing, the first fairing is provided on the circumferential side of the first hub, the first blade is passed through the first fairing, the second fairing is provided on the circumferential side of the second hub and the end of the rotating shaft away from the driving member, the end of the second fairing close to the first fairing is slidably sleeved on the end of the first fairing close to the second fairing and is located on the side of the first hub away from the driving member, or the end of the second fairing close to the first fairing is slidably inserted into the end of the first fairing close to the second fairing and is located on the side of the first hub away from the driving member, and the second blade is passed through the second fairing.

[0015] The aircraft folding propeller mechanism of the embodiment of the present application is provided with an arc-shaped thrust groove on the side of the first hub facing away from the driving member, a first thrust surface is provided at the bottom of the thrust groove, and a thrust block is provided on the side of the second hub facing the first hub and extends into the thrust groove. When the driving member is not working, the second hub can approach the first hub under the action of its own gravity and inertia or under the action of an external force. The thrust block and the thrust groove cooperate to cause the second hub to drive the second blade to rotate, thereby placing the second blade and the first blade in a folded state. When the aircraft folding propeller mechanism is installed on the aircraft, the aircraft does not need to operate the driving member during the flight phase, and the second blade and the first blade automatically enter a folded state, thereby reducing the flight resistance generated by the aircraft during flight, thereby facilitating the improvement of the flight performance of the aircraft. In addition, when the driving member is working, the lift generated by the rotation of the second blade causes the second blade to be in an unfolded state relative to the first blade, thereby facilitating the lifting and hovering of the aircraft.

[0016] An embodiment of the present application also provides an aircraft, including an airframe and the aircraft folding propeller mechanism as described above, wherein the aircraft folding propeller mechanism is installed on the airframe, and the aircraft folding propeller mechanism is used to provide lift during vertical take-off and landing of the aircraft. When the second blade is in the folded state, the extension direction of the second blade and the extension direction of the first blade are the same as the flight direction of the aircraft.

[0017] The aircraft of the present invention provides lift during vertical takeoff and landing by providing a foldable propeller mechanism. The foldable propeller mechanism has a simple structure and utilizes a purely mechanical folding and unfolding method. This mechanism enables the first and second propeller blades to automatically fold during fixed-wing flight, thereby reducing the aircraft's flight resistance and thereby improving the aircraft's flight performance. Furthermore, by aligning the extension direction of the second propeller blade with the first propeller blade when the second propeller blade is folded, and aligning with the aircraft's flight direction, the aircraft's flight resistance during fixed-wing flight can be further reduced, thereby further improving the aircraft's flight performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic diagram of the three-dimensional structure of the aircraft foldable propeller mechanism provided in an embodiment of the present application.

[0019] Figure 2 yes Figure 1 The diagram shown is a three-dimensional structural diagram of the aircraft foldable propeller mechanism without the first fairing and the second fairing.

[0020] Figure 3 yes Figure 1 The exploded structural diagram of the aircraft folding propeller mechanism is shown.

[0021] Figure 4 yes Figure 3 The diagram shows a three-dimensional structure of the first hub in the aircraft foldable propeller mechanism.

[0022] Figure 5 yes Figure 3 The diagram shows a three-dimensional structure of the second hub in the aircraft foldable propeller mechanism.

[0023] Figure 6 yes Figure 3 The diagram shows a three-dimensional structure of the second hub in the aircraft foldable propeller mechanism from another angle.

[0024] Figure 7 yes Figure 3 The diagram shows the exploded structure of the limiting component in the aircraft's foldable propeller mechanism.

[0025] Figure 8 yes Figure 3 The figure shows a schematic diagram of the force analysis between the thrust slot and the thrust block during the deployment of the second blade.

[0026] Figure 9 yes Figure 3 The diagram shows a highly schematic diagram of the movement of the second hub during the deployment of the second blades.

[0027] Figure 10 yes Figure 3 The figure shows a schematic diagram of the force analysis of the second hub during the folding process of the second blade.

[0028] Figure 11 It is a schematic diagram of the three-dimensional structure of the aircraft provided in an embodiment of the present application.

[0029] Description of main component symbols

[0030] Aircraft 1000, aircraft foldable propeller mechanism 100, rotating shaft 10, stop flange 11, driving member 20, first propeller 30, first hub 31, thrust groove 311, first thrust surface 3111, first limiting surface 3112, second limiting surface 3113, first blade 32, second propeller 40, second hub 41, thrust block 411, second thrust surface 4111, guide groove 412, abutting inclined surface 4121, limiting hole 413, second blade 42, thrust elastic member 50, sliding bearing 60, limiting assembly 70, limiting base 71, sliding hole 711, limiting member 72, limiting elastic member 73, first fairing 80, second fairing 90, fuselage 200, fixed propeller mechanism 300. DETAILED DESCRIPTION

[0031] The embodiments of the present application are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present application, and should not be understood as limiting the present application.

[0032] In the description of the present application, it should be understood that the terms indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application. In addition, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, the features defined as "first" and "second" may explicitly or implicitly include one or more of the said features. In the description of the present application, it should be noted that the meaning of "multiple" is two or more, unless otherwise clearly and specifically defined.

[0033] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the term "connection" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, an electrical connection, or mutual communication; it can be directly connected or indirectly connected through an intermediate medium; it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to the specific circumstances. Some embodiments of the present application will be described in detail below with reference to the accompanying drawings.

[0034] See also Figure 1 、 Figure 2 、 Figure 3 and Figure 4 An embodiment of the present application provides a foldable propeller mechanism 100 for an aircraft, including a rotating shaft 10 , a driving member 20 , a first propeller 30 , and a second propeller 40 .

[0035] The driving member 20 may be a motor. The driving member 20 is connected to one end of the rotating shaft 10 and is used to drive the rotating shaft 10 to rotate.

[0036] The first propeller 30 includes a first hub 31 and a first blade 32 connected to each other. The first hub 31 is fixedly connected to the rotating shaft 10. An arc-shaped thrust groove 311 is provided on the side of the first hub 31 facing away from the driving member 20. The thrust groove 311 is concentric with the rotating shaft 10. The bottom of the thrust groove 311 has an inclined first thrust surface 3111. The first thrust surface 3111 extends from one end of the bottom of the thrust groove 311 to the other end.

[0037] The second propeller 40 includes a second hub 41 and a second blade 42 connected to each other. The second hub 41 is movably mounted on the rotating shaft 10 and is located on the side of the first hub 31 away from the driving member 20. The second hub 41 is provided with a thrust block 411 extending into the thrust groove 311 on the side facing the first hub 31. The second blade 42 can drive the second hub 41 to rotate and move away from the first hub 31 under the action of its own lift. The thrust block 411 and the thrust groove 311 cooperate to enable the second blade 42 to be in a folded state or an unfolded state relative to the first blade 32. In the folded state, the circumferential phase difference between the second blade 42 and the first blade 32 is zero. In the unfolded state, the circumferential phase difference between the second blade 42 and the first blade 32 is a preset value. The first thrust surface 3111 is used to abut against the thrust block 411 when the second blade 42 switches between the folded state and the unfolded state.

[0038] Specifically, when the driving member 20 is not working, the second hub 41 can approach the first hub 31 under the action of its own gravity and inertia or under the action of external force, and the thrust block 411 and the thrust groove 311 cooperate to enable the second hub 41 to drive the second blade 42 to rotate. Since the first thrust surface 3111 is inclined, the thrust block 411 eventually moves to the end of the first thrust surface 3111 close to the driving member 20, that is, the lowest position of the first thrust surface 3111. At this time, the phase difference between the angle of the second blade 42 around the rotating shaft 10 and the angle of the first blade 32 around the rotating shaft 10 is zero, and the second blade 42 and the first blade 32 are in a folded state. When the driving member 20 drives the rotating shaft 10 to rotate, the rotating shaft 10 drives the first hub 31 to rotate. The first hub 31 pushes the thrust block 411 through the first thrust surface 3111 to rotate the second hub 41. The second blade 42 generates lift during rotation and drives the thrust block 411 to temporarily separate from the first thrust surface 3111. Then, the first hub 31 drives the first thrust surface 3111 to push the thrust block 411 again. This process repeats and the thrust block 411 is finally located at the end of the first thrust surface 3111 away from the driving member 20, that is, the highest position of the first thrust surface 3111. At this time, the phase difference between the angle of the second blade 42 around the rotating shaft 10 and the angle of the first blade 32 around the rotating shaft 10 is a preset value. In this way, the first blade 32 and the second blade 42 can be automatically folded when the driving member 20 is not working, and automatically unfolded when the driving member 20 is working. When the aircraft folding propeller mechanism 100 is installed on the aircraft 1000 (such as Figure 11 As shown in FIG, when the aircraft 1000 is in the flight phase, the driving member 20 does not need to work. At this time, the first blade 32 and the second blade 42 are automatically folded, thereby reducing the flight resistance generated by the aircraft 1000 during the fixed-wing flight, thereby helping to improve the flight performance of the aircraft 1000.

[0039] In this embodiment, the aircraft foldable propeller mechanism 100 also includes a limit assembly 70, which is arranged on the rotating shaft 10 and is located on the side of the second hub 41 away from the first hub 31. The limit base 71 limits the second hub 41 from being separated from the rotating shaft 10 when the second blade 42 and the first blade 32 are in the unfolded state.

[0040] In some other embodiments, the shape of the thrust block 411 can also be set to be L-shaped or T-shaped, and correspondingly, the shape of the thrust groove 311 can also be set to be L-shaped or T-shaped. Then, the thrust block 411 and the thrust groove 311 cooperate with each other to limit the second hub 41 from being separated from the rotating shaft 10 when the second blade 42 and the first blade 32 are in the expanded state. The embodiments of the present application do not make specific limitations on this.

[0041] In this embodiment, the number of the first blades 32 and the second blades 42 can be multiple and correspond one to one. The multiple first blades 32 are evenly arranged around the first hub 31, and the multiple second blades 42 are evenly arranged around the second hub 41. In the folded state, the circumferential phase difference between each second blade 42 and the corresponding first blade 32 is zero. In the unfolded state, the circumferential phase difference between each second blade 42 and the corresponding first blade 32 is a preset value. For ease of understanding and explanation, in this embodiment, the number of the first blades 32 and the second blades 42 is two. In the unfolded state, the preset value of the circumferential phase difference between each second blade 42 and the corresponding first blade 32 is close to 90 degrees. Obviously, this is not a limitation of the embodiments of the present application.

[0042] In this embodiment, the number of thrust blocks 411 and thrust slots 311 can be multiple and correspond one to one, which is conducive to improving the stability and accuracy of the thrust blocks 411 and thrust slots 311 cooperating to present the second blade 42 in a folded state or an unfolded state relative to the first blade 32.

[0043] In this embodiment, the groove walls at both ends of the thrust groove 311 are respectively a first limiting surface 3112 and a second limiting surface 3113. The first limiting surface 3112 is close to the highest position of the first thrust surface 3111, and the second limiting surface 3113 is close to the lowest position of the first thrust surface 3111. The first limiting surface 3112 is higher than the second limiting surface 3113. When the thrust block 411 abuts the first limiting surface 3112, the second blade 42 and the first blade 32 are in an unfolded state. When the thrust block 411 abuts the second limiting surface 3113, the second blade 42 and the first blade 32 are in a folded state.

[0044] Please refer to Figure 5In this embodiment, the first limiting surface 3112 and the side of the thrust block 411 close to the first limiting surface 3112 are both flat, thereby ensuring that when the second blade 42 and the first blade 32 are in the deployed state, the first limiting surface 3112 and the thrust block 411 have sufficient contact surface. On the one hand, the accuracy of the first limiting surface 3112 limiting the thrust block 411 is improved, and on the other hand, the service life of the first limiting surface 3112 and the thrust block 411 is improved.

[0045] In this embodiment, the thrust block 411 has a second thrust surface 4111 on the side facing the first thrust surface 3111, which is in surface contact with the first thrust surface 3111. The inclination angle of the second thrust surface 4111 is the same as the inclination angle of the first thrust surface 3111. When the second blade 42 and the first blade 32 are in a folded state or an unfolded state, and when the second blade 42 is folding or unfolding, the second thrust surface 4111 abuts against the first thrust surface 3111, thereby increasing the contact area between the thrust block 411 and the first thrust surface 3111, thereby improving the sliding stability of the thrust block 411 in the thrust groove 311, and improving the stability of the first hub 31 rotating by the first thrust surface 3111 pushing the thrust block 411 against the second hub 41.

[0046] In this embodiment, a lubricating liquid (not shown) may be provided between the first thrust surface 3111 and the second thrust surface 4111 , thereby facilitating improvement in the smoothness of sliding of the thrust block 411 in the thrust groove 311 .

[0047] See also Figure 2 and Figure 3 In this embodiment, the aircraft foldable propeller mechanism 100 further includes a thrust elastic member 50, which can be a spring. The thrust elastic member 50 is sleeved on the rotating shaft 10 and is located on the side of the second hub 41 facing away from the first hub 31. One end of the thrust elastic member 50 is connected to the rotating shaft 10, and the other end of the thrust elastic member 50 is drivingly connected to the second hub 41. The thrust elastic member 50 is used to apply pressure to the second hub 41. In this way, the thrust elastic member 50 always provides thrust to the second hub 41 toward the first hub 31. When the driving member 20 stops working, the second blade 42 and the first blade 32 can be quickly adjusted to the folded state. In addition, when the second blade 42 and the first blade 32 are in a folded state, the pressure exerted by the thrust elastic member 50 limits the thrust block 411 to the lowest position of the first thrust surface 3111. The thrust elastic member 50 also cooperates with the first thrust surface 3111 and the second limiting surface 3113 to form a self-locking effect, ensuring that the second blade 42 and the first blade 32 are always in a stable folded state, preventing the second blade 42 from being unfolded due to wind force and the like.

[0048] In this embodiment, the design of the thrust elastic member 50 needs to meet the following conditions:

[0049] During the deployment of the second blade 42 , when the second blade 42 just begins to deploy (at this moment, the second thrust surface 4111 is out of contact with the first thrust surface 3111 ):

[0050] Fp1>=K×dh+F 12 , that is, Fp1- F 12 >=K×dh;

[0051] At the end of the expansion:

[0052] Fp2>=K×(h+dh) + F 12 , that is, Fp2- F 12 >=K×(h+dh);

[0053] During the folding process of the second blade 42, when the second blade 42 just begins to fold (at this time, the second thrust surface 4111 is out of contact with the first thrust surface 3111):

[0054] K×(h+dh)>Fp3+ F 22 ;

[0055] When the second blade 42 is about to be folded:

[0056] K× dh>F 22 ;

[0057] Wherein, K is the stiffness of the thrust elastic member 50, dh is the deformation of the thrust elastic member 50 when the second blade 42 and the first blade 32 are in the folded state, h is the lifting height of the thrust block 411 in the thrust groove 311, h+dh is the deformation of the thrust elastic member 50 when the second blade 42 and the first blade 32 are in the deployed state, Fp1 is the lift of the second blade 42 corresponding to the second blade 42 driving the second hub 41 to start moving at a rotation speed of RPM1, Fp2 is the lift of the second blade 42 corresponding to the second blade 42 being fully deployed at a rotation speed of RPM2, Fp3 is the lift of the second blade 42 corresponding to the second hub 41 starting to move downward at a rotation speed of RPM3, RPM3 is not equal to RPM2, F 12 F is the friction force between the thrust block 411 and the wall of the thrust groove 311 when the second hub 41 moves upward around the rotation axis 10, 22 It is the friction force between the thrust block 411 and the wall of the thrust groove 311 when the second hub 41 moves downward around the rotation axis 10 .

[0058] See also Figure 2 and Figure 3In this embodiment, a stop ridge 11 is provided along the circumference of the shaft 10 at one end of the shaft 10 away from the driving member 20, and an end of the thrust elastic member 50 away from the second hub 41 abuts against the stop ridge 11. This facilitates connection of the thrust elastic member 50 to the shaft 10.

[0059] In some other embodiments, the end of the thrust elastic member 50 away from the second hub 41 may also be connected to the rotating shaft 10 by welding, bolting, etc., which is not specifically limited in the embodiments of the present application.

[0060] See also Figure 2 and Figure 3 In this embodiment, the aircraft foldable propeller mechanism 100 further includes a sliding bearing 60. The sliding bearing 60 is sleeved on the rotating shaft 10 and inserted into the second propeller hub 41. The rotating shaft 10, the second propeller hub 41, and the sliding bearing 60 are coaxial. The end of the thrust elastic member 50 closest to the second propeller hub 41 abuts against the sliding bearing 60. The provision of the sliding bearing 60 facilitates transmission connection between the thrust elastic member 50 and the second propeller hub 41 via the sliding bearing 60. Furthermore, the provision of the sliding bearing 60 improves the accuracy and smoothness of the second propeller hub 41's free rotation and upward and downward sliding about the rotating shaft 10.

[0061] See also Figure 2 、 Figure 3 and Figure 7 In this embodiment, the limiting assembly 70 includes a limiting base 71. The limiting base 71 is disposed on the rotating shaft 10 and located on the side of the second propeller hub 41 facing away from the first propeller hub 31. The limiting base 71 is used to limit the distance between the second propeller hub 41 and the first propeller hub 31 and to transmit the lift generated by the second propeller blade 42 to the rotating shaft 10. Specifically, the limiting base 71 is disposed on the stop ridge 11. When the second propeller blade 42 and the first propeller blade 32 are in the deployed state, the limiting base 71 on the side closest to the second propeller hub 41 abuts against the side of the second propeller hub 41 closest to the limiting base 71, thereby limiting the further upward movement of the second propeller hub 41 along the rotating shaft 10, thereby improving the accuracy of the second propeller blade 42's deployment under its own lift. Furthermore, the lift generated by the second propeller blade 42 can be transmitted to the rotating shaft 10 via the limiting base 71, thereby transmitting the lift to the aircraft 1000 via the driving member 20, enabling the aircraft 1000 to hover and ascend.

[0062] Please refer to Figure 6In this embodiment, an arcuate guide groove 412 is defined on the side of the second propeller hub 41 facing away from the first propeller hub 31. The guide groove 412 is concentric with the rotating shaft 10. The bottom of the guide groove 412 has an inclined abutment slope 4121 extending from one end of the bottom of the guide groove 412 to the other end. The abutment slope 4121 defines a limiting hole 413 at the end away from the first propeller hub 31. The limiting assembly 70 further includes a limiting elastic member 73 and a limiting member 72. The limiting member 72 is slidably inserted into the limiting base 71 and disposed opposite the guide groove 412. The limiting elastic member 73 is disposed within the limiting base 71, and its ends are connected to the limiting base 71 and the limiting member 72, respectively. The limiting elastic member 73 is configured to drive the limiting member 72 into the limiting hole 413 when the second propeller blade 42 is in the deployed state.

[0063] Specifically, the limiting base 71 is provided with a sliding hole 711 on the side facing the second hub 41, the sliding hole 711 is a blind hole, the limiting member 72 can be a pin, the limiting member 72 is slidably arranged in the sliding hole 711, the limiting elastic member 73 can be a spring, the limiting elastic member 73 is arranged in the sliding hole 711, and the two ends of the limiting elastic member 73 are respectively in contact with the bottom of the sliding hole 711 and the limiting member 72.

[0064] When the second blade 42 is in the deployed state and rotates at high speed, if it is necessary to reduce the lift of the first blade 32 and the second blade 42, it is necessary to reduce the rotation speed of the rotating shaft 10. If there is no rotation restriction between the first hub 31 and the second hub 41, the second hub 41 will rotate around the rotating shaft 10 with the second blade 42 due to the influence of the inertial force, which seriously affects the stability of the lift output of the first blade 32 and the second blade 42, thereby affecting the flight control quality and flight safety. By providing a limiting elastic member 73 to drive the limiting member 72 to be inserted into the limiting hole 413 when the second blade 42 is in the deployed state, it is possible to effectively avoid relative rotation between the first hub 31 and the second hub 41 due to inertia when the first blade 32 and the second blade 42 are in normal working state, thereby helping to improve the flight control quality and flight safety of the aircraft 1000. In addition, by providing a limiting elastic member 73 and providing an abutment slope 4121 at the bottom of the guide groove 412, when the second blade 42 changes from the unfolded state to the folded state, the limiting elastic member 73 can also drive the limiting member 72 to squeeze the abutment slope 4121, thereby providing a thrust toward the first hub 31 to the second hub 41, thereby improving the efficiency of adjusting the second blade 42 and the first blade 32 to the folded state.

[0065] In this embodiment, when the second blade 42 and the first blade 32 are in a folded state, the axis of the limiting hole 413 intersects perpendicularly with the mounting axis (not shown) of the first blade 32. When the second blade 42 and the first blade 32 are in an unfolded state, the axis of the limiting hole 413 is perpendicular to the mounting axis of the first blade 32 and the phase difference around the rotation axis 10 is a preset value.

[0066] In other embodiments, the limiting member 72 and the limiting elastic member 73 can be eliminated, and a first friction surface (not shown) and a second friction surface (not shown) can be provided on the side of the second hub 41 facing the limiting base 71 and on the side of the limiting base 71 facing the second hub 41, respectively. This can increase the friction between the second hub 41 and the limiting base 71 to limit relative rotation between the first hub 31 and the second hub 41 during deceleration. Alternatively, a mortise and tenon structure (not shown) or a tenon-and-slot structure (not shown) can be provided on the side of the second hub 41 facing the limiting base 71 and on the side of the limiting base 71 facing the second hub 41, respectively. This can limit relative rotation between the first hub 31 and the second hub 41 during deceleration through the cooperation of the mortise and tenon structure or the tenon-and-slot structure. This embodiment of the present application is not specifically limited to this.

[0067] See also Figure 1 and Figure 3 In this embodiment, the aircraft foldable propeller mechanism 100 also includes a first fairing 80 and a second fairing 90. The first fairing 80 is arranged on the circumferential side of the first hub 31, and the first blade 32 is inserted into the first fairing 80. The second fairing 90 is arranged on the circumferential side of the second hub 41 and the end of the rotating shaft 10 away from the driving member 20. The end of the second fairing 90 close to the first fairing 80 is slidably sleeved on the end of the first fairing 80 close to the second fairing 90 and is located on the side of the first hub 31 away from the driving member 20, or the end of the second fairing 90 close to the first fairing 80 is slidably inserted into the end of the first fairing 80 close to the second fairing 90 and is located on the side of the first hub 31 away from the driving member 20, and the second blade 42 is inserted into the second fairing 90.

[0068] By providing the first fairing 80 and the second fairing 90, the drag of the aircraft 1000 during flight can be effectively reduced, thereby facilitating improved flight performance of the aircraft 1000. In addition, by arranging that the end of the second fairing 90 proximate to the first fairing 80 is slidably mounted on the end of the first fairing 80 proximate to the second fairing 90, or the end of the second fairing 90 proximate to the first fairing 80 is slidably inserted into the end of the first fairing 80 proximate to the second fairing 90, when the second blades 42 and the first blades 32 are in the deployed state, the second fairing 90 and the first fairing 80 are not separated in the axial direction, thereby effectively preventing airflow from entering between the second fairing 90 and the first fairing 80 and increasing the drag of the aircraft 1000 during flight, thereby further facilitating improved flight performance of the aircraft 1000.

[0069] The process of unfolding the second blade 42 of the aircraft foldable propeller mechanism 100 according to the embodiment of the present application is roughly as follows:

[0070] Step 1: After receiving a signal from the control system of the aircraft 1000 , the driving member 20 drives the rotating shaft 10 to rotate from a stationary state and gradually increases the speed to a desired range, thereby driving the first propeller hub 31 to rotate.

[0071] Step 2: Since the second thrust surface 4111 of the thrust block 411 on the second hub 41 is pressed against the first thrust surface 3111 , when the first hub 31 starts to rotate, the first thrust surface 3111 and the second thrust surface 4111 will simultaneously push the second hub 41 to rotate.

[0072] Step 3: As the rotation speed increases, the second blade 42 will generate an upward lift until the lift exceeds the thrust generated by the compression of the thrust elastic member 50 . Then, the second hub 41 will move upward toward the rotating shaft 10 under the lift of the second blade 42 .

[0073] Step 4: When the second hub 41 moves upward, the first thrust surface 3111 and the second thrust surface 4111 will separate, and the second hub 41 will instantly lose its rotational power. Theoretically, the rotation speed will not increase or may even decrease at the moment of separation.

[0074] Step 5: After the first thrust surface 3111 and the second thrust surface 4111 separate, the first hub 31 continues to accelerate, so the first thrust surface 3111 quickly catches up with the second thrust surface 4111 and maintains contact. At this point, the angles of the first blade 32 and the second blade 42 around the rotation axis 10 will have a certain phase difference.

[0075] Step 6: Repeat steps 2 to 5, the limiting member 72 gradually abuts against the abutting inclined surface 4121 and the limiting elastic member 73 is compressed until the phase difference between the angles of the first blade 32 and the second blade 42 around the rotating shaft 10 is close to 90 degrees. Since the first limiting surface 3112 and the thrust block 411 cooperate to limit, and the limiting elastic member 73 drives the limiting member 72 to be inserted into the limiting hole 413 for limiting, the phase difference between the angles of the first blade 32 and the second blade 42 around the rotating shaft 10 will be maintained at about 90 degrees. At this time, the first blade 32 and the second blade 42 are in the expanded state.

[0076] See also Figure 8 and Figure 9 During the unfolding of the second blade 42, the height h of the thrust block 411 of the second hub 41 in the thrust groove 311 and the distance h1 between the side of the second hub 41 facing the limiting base 71 and the side of the limiting base 71 facing the second hub 41 when the second blade 42 is in the folded state satisfy the following relationship: h1>=h, preferably, h1=h.

[0077] In addition, after the second thrust surface 4111 contacts the first thrust surface 3111, the interaction force F1 between the thrust block 411 and the first thrust surface 3111 perpendicular to the first thrust surface 3111 is: , where Fx1 is the interaction force between the thrust block 411 and the first thrust surface 3111 in the horizontal direction when the second hub 41 rotates around the rotating shaft 10, the component Fx1 symmetrically distributed around the axis of rotation 10 provides the torque for the second hub 41 to rotate around the rotating shaft 10, and Fz1 is the thrust for the second hub 41 to move upward along the rotating shaft 10.

[0078] The folding process of the second blade 42 of the aircraft foldable propeller mechanism 100 according to the embodiment of the present application is roughly as follows:

[0079] Step 1: After receiving a signal from the control system of the aircraft 1000 , the driving member 20 gradually stops working, and drives the first propeller hub 31 and the rotating shaft 10 to gradually stop rotating.

[0080] Step 2: When the second blade 42 gradually decreases its speed following the second hub 41, the lift generated by the second blade 42 will gradually decrease. Therefore, under the thrust of the thrust elastic member 50 and the gradually decreasing lift of the second blade 42, the second hub 41 will gradually move toward the first hub 31 until the limiting member 72 disengages from the limiting hole 413.

[0081] Step 3: After the stopper 72 is released from the stopper hole 413, the first hub 31 experiences a faster speed reduction due to the resistance of the driving member 20. Since the second blade 42 and the second hub 41 can rotate about the rotation axis 10, the second hub 41 rotates in the folding direction about the rotation axis 10 under the thrust of the thrust elastic member 50 and its own inertia, until the thrust block 411 contacts the second stopper surface 3113, and the second blade 42 is folded. During this step, because the first hub 31 decelerates faster, the first thrust surface 3111 and the second thrust surface 4111 remain separated or in weak contact.

[0082] Step 4: After the second blade 42 is folded, even when the aircraft 1000 is flying at high speed, the second blade 42 cannot generate significant lift, so the first thrust surface 3111 and the second thrust surface 4111 always maintain contact. Because the first thrust surface 3111 and the second thrust surface 4111 are inclined surfaces, the thrust block 411, under the thrust of the thrust elastic member 50, forms a self-locking effect with the first thrust surface 3111 and the second stop surface 3113, thereby forming a stable folded state for the second blade 42 and the first blade 32.

[0083] See also Figure 10 During the folding process of the second blade 42, when the speed of the driving member 20 decreases and the second blade 42 needs to be folded, the force analysis of the second hub 41 is as follows: Fz 21 >Fz 22 + Fz 23 , where Fz 21 is the thrust applied to the second hub 41 by the thrust elastic member 50 after being compressed, Fz 22 Fz is the friction force generated between the thrust block 411 and the wall of the thrust groove 311 when the second hub 41 moves downward along the shaft 10, 23 is the lift generated when the second blade 42 rotates. When the above relationship is satisfied, the second hub 41 will move downward along the rotating shaft 10.

[0084] In addition, when the driving member 20 reduces its rotational speed, the first hub 31 will reduce its rotational speed synchronously because it is directly connected to the driving member 20 through the rotating shaft 10, while the second hub 41 will have a rotational speed change lower than that of the first hub 31 due to the inertia force. Therefore, during the folding process of the second blade 42, a gap ds can always be maintained between the second thrust surface 4111 and the first thrust surface 3111, which provides space for the second hub 41 to move downward along the rotating shaft 10.

[0085] To sum up, the aircraft folding propeller mechanism 100 of the embodiment of the present application is provided with an arc-shaped thrust groove 311 on the side of the first hub 31 facing away from the driving member 20, a first thrust surface 3111 is provided at the bottom of the thrust groove 311, and a thrust block 411 is protruded from the side of the second hub 41 facing the first hub 31 and extends into the thrust groove 311. When the driving member 20 is not working, the second hub 41 can approach the first hub 31 under the action of its own gravity and inertia or under the action of external force, and the thrust block 411 and the thrust groove 311 cooperate to enable the second hub 41 to drive the second blade 42 to rotate, so that the second blade 42 and the first blade 32 are in a folded state. When the foldable propeller mechanism 100 is installed on the aircraft 1000, the second blade 42 and the first blade 32 are automatically folded when the aircraft 1000 is in flight and the driving member 20 is not required to operate. This reduces the flight resistance of the aircraft 1000 during flight and improves the flight performance of the aircraft 1000. In addition, when the driving member 20 is in operation, the lift generated by the rotation of the second blade 42 causes the second blade 42 to be deployed relative to the first blade 32, thereby facilitating the ascent, descent, and hovering of the aircraft 1000.

[0086] Furthermore, the aircraft foldable propeller mechanism 100 of the present embodiment can automatically follow the operating state of the drive element 20 to actively deploy and fold the first and second blades 32, 42. This purely mechanical structure offers simplicity, reliable functionality, minimal space consumption, and low weight. Furthermore, it does not require an electrically driven device such as a servo (not shown) to assist in deploying and folding the first and second blades 32, 42, thereby reducing system complexity, verification costs, and material costs. During flight of the aircraft 1000, the pilot or flight control system does not need to actively control the deployment and folding process, simplifying control system design and reducing the pilot's operational burden. Furthermore, because the first and second blades 32, 42 can actively deploy and fold according to the operating state of the drive element 20, the aircraft foldable propeller mechanism 100 can be used for stall protection during stationary flight, thereby improving the safety of the aircraft 1000.

[0087] Please refer to Figure 11 The present application also provides an aircraft 1000, comprising an airframe 200 and the above-described foldable propeller mechanism 100. The foldable propeller mechanism 100 is mounted on the airframe 200 and is configured to provide lift during vertical takeoff and landing of the aircraft 1000. When the second blades 42 are folded, the extension direction of the second blades 42 and the extension direction of the first blades 32 are the same as the flight direction of the aircraft 1000. Specifically, the driving member 20 of the foldable propeller mechanism 100 is connected to the airframe 200.

[0088] The aircraft 1000 of the embodiment of the present application is provided with a foldable propeller mechanism 100 to provide lift during vertical takeoff and landing. The foldable propeller mechanism 100 has a simple structure and is folded and unfolded purely mechanically. This mechanism enables the first blade 32 and the second blade 42 to automatically fold during fixed-wing flight of the aircraft 1000, thereby reducing the flight resistance of the aircraft 1000 and thereby improving the flight performance of the aircraft 1000. Furthermore, by arranging that the extension direction of the second blade 42 and the extension direction of the first blade 32 are aligned with the flight direction of the aircraft 1000 when the second blade 42 is in the folded state, the flight resistance generated by the aircraft 1000 during fixed-wing flight can be further reduced, thereby further improving the flight performance of the aircraft 1000.

[0089] In this embodiment, the aircraft 1000 also includes a fixed propeller mechanism 300 installed on the body 200. The fixed propeller mechanism 300 is used to provide lift when the aircraft 1000 takes off and lands vertically, and to provide pull or thrust when the aircraft 1000 is flying. By setting up the fixed propeller mechanism 300, the flight performance of the aircraft 1000 can be further improved.

[0090] It will be apparent to those skilled in the art that the present application is not limited to the details of the exemplary embodiments described above, and that the present application can be implemented in other specific forms without departing from the spirit or essential characteristics of the present application. Therefore, the embodiments should be considered in all respects as illustrative and non-restrictive, and the scope of the present application is defined by the appended claims rather than the foregoing description, and all variations that come within the meaning and range of equivalents of the claims are intended to be embraced herein.

[0091] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application and are not intended to limit the present application. Although the present application has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present application may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present application.

Claims

1. A foldable propeller mechanism for an aircraft, characterized in that: include: shaft; a driving member connected to one end of the rotating shaft and used to drive the rotating shaft to rotate; a first propeller, comprising a first propeller hub and a first propeller blade connected to each other, the first propeller hub being fixedly connected to the rotating shaft, a side of the first propeller hub facing away from the driving member being provided with an arc-shaped thrust groove, a bottom of the thrust groove being provided with an inclined first thrust surface; a second propeller, comprising a second propeller hub and a second propeller blade connected thereto, the second propeller hub being movably sleeved on the rotating shaft and located on a side of the first propeller hub facing away from the driving member, a thrust block protruding from a side of the second propeller hub facing the first propeller hub and extending into the thrust groove, the thrust block and the thrust groove cooperating to enable the second propeller blade to be in a folded state or an unfolded state relative to the first propeller blade, wherein in the folded state, the circumferential phase difference between the second propeller blade and the first propeller blade is zero, and in the unfolded state, the circumferential phase difference between the second propeller blade and the first propeller blade is a preset value, and the first thrust surface is configured to abut against the thrust block when the second propeller blade switches between the folded state and the unfolded state; The aircraft foldable propeller mechanism further includes a limiting assembly, the limiting assembly including a limiting base, the limiting base being provided on the rotating shaft and located on a side of the second propeller hub facing away from the first propeller hub, the limiting base being used to limit the distance between the second propeller hub and the first propeller hub, and being used to transmit the lift generated by the second blade to the rotating shaft; An arc-shaped guide groove is provided on the side of the second hub facing away from the first hub, the guide groove is concentric with the rotating shaft, the bottom of the guide groove has an abutment slope, and a limiting hole is provided on the end of the abutment slope away from the first hub; the limiting assembly also includes a limiting elastic part and a limiting part, the limiting part is slidably inserted in the limiting base and arranged opposite to the guide groove, the limiting elastic part is arranged in the limiting base, and the two ends of the limiting elastic part are respectively connected to the limiting base and the limiting part, and the limiting elastic part is used to drive the limiting part to be inserted into the limiting hole when the second blade is in the expanded state.

2. The aircraft foldable propeller mechanism according to claim 1, wherein: The aircraft foldable propeller mechanism also includes a thrust elastic member, which is sleeved on the rotating shaft and located on the side of the second hub facing away from the first hub. One end of the thrust elastic member is connected to the rotating shaft, and the other end of the thrust elastic member is transmission-connected to the second hub. The thrust elastic member is used to apply pressure to the second hub.

3. The aircraft foldable propeller mechanism according to claim 2, wherein: The aircraft foldable propeller mechanism further includes a sliding bearing, which is sleeved on the rotating shaft and inserted into the second propeller hub. One end of the thrust elastic member close to the second propeller hub abuts against the sliding bearing.

4. The aircraft foldable propeller mechanism according to claim 2, wherein: One end of the rotating shaft away from the driving member is provided with a stop ridge along the circumference of the rotating shaft, and one end of the thrust elastic member away from the second hub abuts against the stop ridge.

5. The aircraft foldable propeller mechanism according to claim 1, wherein: A side of the second hub facing the limiting base and a side of the limiting base facing the second hub respectively have a first friction surface and a second friction surface that match each other; or, A side of the second hub facing the limiting base and a side of the limiting base facing the second hub are respectively provided with matching mortise and tenon structures.

6. The aircraft foldable propeller mechanism according to claim 1, wherein: The thrust block has a second thrust surface on a side facing the first thrust surface, which is in surface contact with the first thrust surface.

7. The aircraft foldable propeller mechanism according to claim 1, wherein: The aircraft folding propeller mechanism also includes a first fairing and a second fairing, the first fairing is provided on the circumferential side of the first hub, the first blade is passed through the first fairing, the second fairing is provided on the circumferential side of the second hub and the end of the rotating shaft away from the driving member, the end of the second fairing close to the first fairing is slidably sleeved on the end of the first fairing close to the second fairing and is located on the side of the first hub away from the driving member, or the end of the second fairing close to the first fairing is slidably inserted into the end of the first fairing close to the second fairing and is located on the side of the first hub away from the driving member, and the second blade is passed through the second fairing.

8. An aircraft, characterized in that: It comprises an airframe and an aircraft foldable propeller mechanism as described in any one of claims 1 to 7, wherein the aircraft foldable propeller mechanism is installed on the airframe, and the aircraft foldable propeller mechanism is used to provide lift when the aircraft takes off and lands vertically, and when the second blade is in the folded state, the extension direction of the second blade and the extension direction of the first blade are the same as the flight direction of the aircraft.

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