An unmanned aerial vehicle propeller adjusting mechanism

Abstract

The application relates to the technical field of unmanned planes, in particular to a propeller adjusting mechanism for unmanned planes, which comprises a fixing shaft assembly, a rotating shaft assembly, an actuating assembly, an actuating block, a propeller assembly, a ratchet assembly and a linear driving assembly. The linear driving assembly is connected with the output end through a first axial bearing and a limiting structure on the hollow shaft assembly, and is used for driving the hollow shaft assembly to move along the axial direction, so that the actuating block is pushed to move through the limiting structure on the hollow shaft assembly, the propeller root base of the propeller assembly is separated from the axial guide structure through the clamp structure, and the propeller root base is stopped by rotating the ratchet assembly in the fairing until the end face of the propeller root base is close to the ratchet assembly in the fairing and the rotating speed of the propeller assembly is reduced. When the medium and large unmanned planes are in the landing mode of gliding and parachute descending, the propeller can be safely collected in the designated position, and the propeller or the engine is prevented from being damaged.

Description

Technical Field

[0001] This invention relates to the field of unmanned aerial vehicle (UAV) technology, and more specifically to a UAV propeller control mechanism with adjustable propeller position. Background Technology

[0002] When a drone lands by taxi or parachute, the propeller is often spinning. At this time, due to the instability of the aircraft's attitude, the propeller is very likely to touch the ground, causing damage to the propeller or engine.

[0003] Existing propeller-pulling mechanisms are mostly based on quadcopter drones and rely on equipment outside the drone for recovery. Because rotary-wing drones are small and lightweight, they can be recovered using other recovery equipment. However, medium and large-sized drones are larger and heavier, have a faster landing speed, and a larger landing range than small quadcopter drones, so relying on external equipment for propeller-pulling recovery is not very practical.

[0004] Therefore, there is a need to provide a drone propeller control mechanism with adjustable propeller position to solve the above problems. Summary of the Invention

[0005] To address the problem of difficulty in retrieving propellers from medium and large-sized drones, this invention provides a drone propeller-adjusting mechanism with adjustable propeller position to solve the existing problem.

[0006] The present invention provides an adjustable propeller position unmanned aerial vehicle propeller control mechanism, which adopts the following technical solution, including: The fixed axis assembly has one end fixed to the body of the drone, and the other end extends out of the body of the drone and is connected to the fairing. The actuation component is fitted onto the fixed shaft assembly between the outer wall of the fuselage and the fairing, and can slide and rotate along the fixed shaft assembly. Two opposing limiting structures are provided on its outer periphery. A rotating shaft assembly includes a hollow shaft assembly, which is sleeved between two limiting structures of an actuating assembly. A limiting groove matching the limiting structure is opened on the hollow shaft assembly along the axial direction. An axial guide structure is located in the middle of the hollow shaft assembly, and the end of the hollow shaft assembly is connected to the output end of the engine through a transmission assembly. The blade assembly has a blade root base on its blade root. The blade root base is axially slidably connected to the hollow shaft assembly through an axial guide structure. The blade root base of the blade assembly is constrained between the clamp structure and the outer periphery of the hollow shaft assembly by two clamp structures. An actuator is sleeved on the hollow shaft assembly, and the actuator is slidably connected to the hollow shaft assembly along the axial direction through an axial guide structure; A ratchet assembly, located within the fairing, is used to limit the rotation direction of the propeller root base and decelerate the propeller root base when it is engaged with the ratchet assembly. And a linear drive assembly, the output end of which is connected to the limiting structure on the first axial bearing and the hollow shaft assembly. It is used to drive the hollow shaft assembly to move axially, so as to push the actuator block to move through the limiting structure on the hollow shaft assembly, so that the actuator block pushes the blade root base of the blade assembly to disengage from the axial guide structure through the clamp structure, until the blade assembly speed decreases and the end face of the blade root base is pressed against the ratchet assembly in the fairing and rotates to the stop structure.

[0007] A further technical solution of the present invention includes a ratchet assembly comprising: a ratchet disc, which is fitted and fixed inside the fairing, and a plurality of ratchet teeth are evenly distributed on one side of the ratchet disc facing the end face of the propeller root base.

[0008] In a further technical solution of the present invention, the ratchet is a protrusion that gradually increases in height along the direction of blade rotation.

[0009] A further technical solution of the present invention includes a stop structure comprising: a stop protrusion disposed between two adjacent ratchet teeth, wherein the height of the stop protrusion is half the maximum height of the ratchet teeth.

[0010] A further technical solution of the present invention includes a hollow shaft assembly comprising: The first hollow shaft has a limiting groove. And a second hollow shaft, one end of which is coaxially connected to the end of the first hollow shaft opposite to the limiting groove. An axial guide structure is provided on the outer periphery of the end of the second hollow shaft facing the first hollow shaft, and a bearing assembly is provided on the end of the second hollow shaft opposite to the first hollow shaft.

[0011] A further technical solution of the present invention includes an axial guide structure comprising: a plurality of limiting blocks evenly distributed in the circumferential direction of the second hollow shaft, one end of the limiting block being used to cooperate with a limiting groove provided on the propeller root base, and the other end of the limiting block being used to slide to connect with a guide groove provided on the inner wall of the mounting hole in the middle of the actuating block.

[0012] In a further technical solution of the present invention, a transmission gear is coaxially provided at the end of the first hollow shaft opposite to the second hollow shaft, and the transmission gear is connected to the output gear at the output end of the engine.

[0013] A further technical solution of the present invention includes an actuation component comprising an actuation cylinder, wherein the limiting structure comprises a plurality of L-shaped members, the plurality of L-shaped members being evenly distributed on the outer peripheral surface near the end of the actuation cylinder, one end of the L-shaped member being fixed to the outer peripheral surface of the end of the actuation cylinder, the other end of the L-shaped member being a free end, and the free ends of the L-shaped members of the two limiting structures being opposite to each other.

[0014] A further technical solution of the present invention includes a bearing assembly comprising: a radial rolling bearing, the inner ring of which is fixedly fitted onto a second hollow shaft, and an axial sliding bearing, the outer ring of which is fixedly fitted onto an axial sliding bearing, wherein the end of the radial rolling bearing is close to the end face of the limiting block.

[0015] A further technical solution of the present invention includes: a second axial bearing, which is sleeved on the axial sliding bearing of the bearing assembly, one end of which is used to contact the free end of the L-shaped part of the limiting structure of the second hollow shaft away from the transmission gear, and the other end of which is used to contact the end face of the propeller root base.

[0016] The beneficial effects of this invention are: The linear drive component pushes the hollow shaft assembly axially, which in turn pushes the actuator block through the limiting structure on the hollow shaft assembly. This causes the actuator block to push the blade root base of the blade assembly to disengage from the axial guide structure on the hollow shaft assembly through the clamping structure. This continues until the blade assembly speed decreases and the end face of the blade root base is pressed against the ratchet assembly inside the fairing, rotating until it stops at the stop structure. In other words, the blade root base gradually decelerates after contacting the ratchet assembly and finally stops after contacting the stop structure. At the same time, the ratchet assembly prevents the blade assembly from reversing due to gravity, ultimately limiting the position of the blade root base of the blade assembly. Therefore, this invention enables medium and large UAVs to safely retract the propeller to a designated position during gliding and parachute landings, avoiding damage to the propeller or engine. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention 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 the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of the overall structure of an adjustable propeller position unmanned aerial vehicle propeller control mechanism according to the present invention. Figure 2 for Figure 1 Assembly drawing of the fixed shaft assembly, fairing, and ratchet assembly; Figure 3 for Figure 1 Schematic diagram of the central shaft assembly; Figure 4 for Figure 1 A schematic diagram of the structure of the actuator assembly; Figure 5 for Figure 1 Schematic diagram of the actuator block in the diagram; Figure 6 for Figure 1A schematic diagram of the structure of the second axial bearing in the diagram; Figure 7 for Figure 1 Schematic diagram of the rear rotor root clamp structure; Figure 8 for Figure 1 A schematic diagram of the front rotor root clamp structure; Figure 9 for Figure 1 Schematic diagram of the middle blade propeller assembly; Figure 10 This is a schematic diagram showing the state of the blades of the propeller assembly when the blades are deployed. Figure 11 A schematic diagram of the blade state of the blade assembly after the propeller mechanism has been adjusted. Figure 12 for Figure 1 Axial sectional view.

[0019] In the diagram: 1. Fixed shaft assembly; 1-1. Shaft; 1-2. Fairing; 1-3. Ratchet disc; 1-4. Ratchet tooth; 1-5. Stop protrusion; 2. Rotating shaft assembly; 2-1. First hollow shaft; 2-2. Limiting slot; 2-3. Second hollow shaft; 2-4. Bearing assembly; 2-5. Limiting block; 2-6. Transmission gear; 3. Actuating assembly; 3-1. Actuating cylinder; 3-2. First limiting structure; 3-3. Second limiting structure; 3-4. 1. First axial bearing; 4. Actuating block; 5. Second axial bearing; 6. Rear propeller root clamp; 6-1. Rear propeller root clamp ring; 6-2. Rear propeller root clamp base; 7. Front propeller root clamp; 7-1. Front propeller root clamp ring; 7-2. Front propeller root clamp outer flange; 7-3. Front propeller root clamp inner flange; 8. Blade assembly; 8-1. Blade; 8-2. Propeller root base; 8-3. Front propeller root clamp groove; 8-4. Rear propeller root clamp groove; 8-5. Limiting groove. Detailed Implementation

[0020] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] An embodiment of the adjustable propeller position unmanned aerial vehicle propeller control mechanism of the present invention, such as... Figure 1As shown, it includes: a fixed shaft assembly 1, a rotating shaft assembly 2, an actuating assembly 3, an actuating block 4, a propeller assembly 8, a ratchet assembly, and a linear drive assembly. One end of the fixed shaft assembly 1 is fixed to the body of the UAV, and the other end of the fixed shaft assembly 1 extends out of the body of the UAV and is connected to a fairing 1-2. The actuating assembly 3 is sleeved on the fixed shaft assembly 1 between the outer wall of the body and the fairing 1-2, and can slide and rotate along the fixed shaft assembly 1. Two opposing limiting structures are provided on its outer periphery. The rotating shaft assembly 2 includes a hollow shaft assembly, which is sleeved between the two limiting structures of the actuating assembly 3. A limiting groove 2-2 matching the limiting structure is opened on the hollow shaft assembly along the axial direction. The axially guided structure is used, and the end of the hollow shaft assembly is connected to the output end of the engine via a transmission assembly. The blade assembly 8 includes four blades 8-1, and a blade root base 8-2 is provided on the root of each blade 8-1. The blade root base 8-2 is axially slidably connected to the hollow shaft assembly via the axially guided structure, and the blade root base 8-2 of the blade assembly 8 is constrained between the clamping structure and the outer periphery of the hollow shaft assembly by two clamping structures. Specifically, two blade root clamping grooves are provided on the outer peripheral surfaces at both ends of the blade root base 8-2, and the blade root clamping grooves cooperate with the corresponding clamping structures. Figure 5 As shown, the actuator 4 is sleeved on the hollow shaft assembly, and the actuator 4 is axially slidably connected to the hollow shaft assembly through an axial guide structure; the ratchet assembly is set inside the fairing 1-2, and is used to limit the rotation direction of the blade root base 8-2 and decelerate the blade root base 8-2 when it is in contact with the ratchet assembly, and a stop structure is provided on it; the output end of the linear drive assembly is connected to the limiting structure on the hollow shaft assembly through the first axial bearing 3-4, and the linear drive assembly adopts a linear motor. The linear drive assembly is used to drive the hollow shaft assembly to move axially, so as to push the actuator 4 to move through the limiting structure on the hollow shaft assembly, so that the actuator 4 pushes the blade root base 8-2 of the blade assembly 8 to disengage from the axial guide structure through the clamp structure, until the speed of the blade assembly 8 decreases and the end face of the blade root base 8-2 is in close contact with the ratchet assembly inside the fairing 1-2 and rotates to the stop structure.

[0022] For example, such as Figure 2 As shown, the fixed shaft assembly 1 includes a shaft 1-1. One end of the shaft 1-1 is fixed to the body of the UAV, and the other end of the fixed shaft assembly 1 extends out of the body of the UAV and is connected to a fairing 1-2. It should be noted that the shaft 1-1 cooperates with the actuation component 3, and the relative rotation and relative sliding between the shaft 1-1 and the actuation component 3 are achieved by the inner and outer cooperation of the axial sliding bearing and the radial rolling bearing. The fairing 1-2 is a pointed cone-shaped fairing with uniform thickness, which can reduce drag and protect the rear components. The inner side of the pointed cone front end of the fairing 1-2 is fixedly connected to the shaft 1-1.

[0023] For example, such as Figure 3As shown, in one specific embodiment, the hollow shaft assembly includes: a first hollow shaft 2-1 and a second hollow shaft 2-3. A limiting groove 2-2 is formed on the first hollow shaft 2-1. One end of the second hollow shaft 2-3 is coaxially connected to the end of the first hollow shaft 2-1 opposite to the limiting groove 2-2. An axial guide structure is disposed on the outer periphery of the end of the second hollow shaft 2-3 facing the first hollow shaft 2-1. A bearing assembly 2-4 is disposed on the end of the second hollow shaft 2-3 opposite to the first hollow shaft 2-1. A transmission gear 2-6 is coaxially disposed on the end of the first hollow shaft 2-1 opposite to the second hollow shaft 2-3. The transmission gear 2-6 is connected to the output gear at the engine output end. Specifically, as shown... Figure 1 and 3 As shown, the axial guide structure includes multiple limiting blocks 2-5 evenly distributed around the second hollow shaft 2-3. One end of each limiting block 2-5 engages with a limiting groove 8-5 on the propeller root base 8-2, and the other end slides with a guide groove located on the inner wall of the mounting hole in the middle of the actuator block 4. It should be noted that the hollow shaft assembly is the structure that transmits torque to the engine and drives the propeller and other components to rotate around the shaft. Relative to the engine, it only rotates along the x-axis. The hollow shaft assembly is coaxially connected to a first hollow shaft 2-1 with different outer diameters and a second hollow shaft 2-3 with the same inner diameter. The hollow shaft assembly is mounted on the actuator 3, and the two only slide relative to each other along the x-axis, achieved using an axial sliding bearing.

[0024] For example, such as Figure 4 As shown, in one specific embodiment, the actuation component 3 includes: an actuation cylinder 3-1, on which two opposing limiting structures are provided, wherein the two limiting structures are a first limiting structure 3-2 and a second limiting structure 3-3, and both the first limiting structure 3-2 and the second limiting structure 3-3 include: a plurality of L-shaped members, the plurality of L-shaped members being evenly distributed on the outer peripheral surface near the end of the actuation cylinder 3-1, one end of the L-shaped member being fixed to the outer peripheral surface of the end of the actuation cylinder 3-1, and the other end of the L-shaped member being a free end, and the free ends of the L-shaped members of the two limiting structures being opposite to each other. It should be noted that, as Figure 4As shown, the L-shaped component of the first limiting structure 3-2 includes a connecting plate. One end of the connecting plate is fixedly mounted on the actuator cylinder 3-1 radially, and the other end of the connecting plate is connected to an arc-shaped plate, with the inner arc surface of the arc-shaped plate facing the outer circumferential surface of the actuator cylinder 3-1. The arc-shaped plates of the multiple L-shaped components of the first limiting structure 3-2 are located within the same circular surface. The L-shaped component of the second limiting structure 3-3 includes two connecting rods. One end of one connecting rod is fixedly mounted on the actuator cylinder 3-1 radially, and the end of the connecting rod is vertically connected to another connecting rod. It should be noted that the three L-shaped components of the second limiting structure 3-3 of the actuator cylinder 3-1 are embedded in the three limiting slots 2-2 on the first hollow shaft 2-1. Three limiting blocks 2-5 are provided at the rear end of the large rotating shaft 2-3. The limiting blocks 2-5 are flush with the rear end of the large rotating shaft 2-3 and are used to fix the blades rotating around the x-axis. The output torque of the engine is transmitted by the transmission gear 2-6. The actuator 3-1 is a structure of the propeller mechanism used to transmit force in the x-direction. It is used to push the blade assembly 8 onto the ratchet disk 1-3 inside the fairing 1-2 on the shaft 1 to achieve propeller deceleration and stopping. The actuator shaft 3 can rotate with the rotating shaft 2 and move in the x-direction. Specifically, the actuator 3-1 uses rolling bearings and sliding bearings to cooperate with the shaft 1-1 to achieve relative rotation and relative sliding in the x-direction between the actuator 3-1 and the shaft 1-1. The first limiting structure 3-2 and the second limiting structure 3-3 provide fixation and control in the x-direction for the rotating shaft assembly 2, the actuator block 4, the second axial bearing 5, the rear rotor root clamp 6, and the front rotor root clamp 7. The transmission of force in the x-direction is accomplished by the first axial bearing 3-4 mounted on the second limiting structure 3-3. The side of the first axial bearing 3-4 facing away from the second limiting structure 3-3 has three cylindrical protrusions, which serve as the points of application for the x-direction force. Since the first axial bearing 3-4 is an axial bearing, when a linear force is applied to the cylindrical protrusions, the actuator cylinder 3-1 only moves along the x-direction under the action of the first axial bearing 3-4 and does not rotate around the x-axis. That is, the x-direction force transmitted from the second limiting structure 3-3 on the actuator block 4 is evenly transmitted to the clamp assembly, and the three evenly distributed protrusions on the front of the actuator block 4 contact the clamp assembly. The actuator block 4 is mounted on the rear rotor root clamp 6, with its inner edge conforming to the rear rotor root clamp 6. The rear surface of the actuator block 4 is flush with the rear surface of the limit blocks 2-5.

[0025] For example, such as Figure 2As shown, in one specific embodiment, the ratchet assembly includes: a ratchet disc 1-3, which is fitted and fixed inside the fairing 1-2. Multiple ratchet teeth 1-4 are evenly distributed on the side of the ratchet disc 1-3 facing the end face of the propeller root base 8-2. In this embodiment, the ratchet teeth 1-4 are protrusions that gradually increase in height along the direction of propeller rotation. In another specific embodiment, the stop structure includes: a stop protrusion 1-5, which is disposed between two adjacent ratchet teeth 1-4, and the height of the stop protrusion 1-5 is half the maximum height of the ratchet teeth. It should be noted that, along the direction of propeller rotation... Figure 2 Looking along the x-axis, clockwise, the starting point of a single ratchet 1-4 is flush with the surface of the ratchet disc 1-3, and the ending point is a protrusion higher than the surface of the ratchet disc 1-3. In this embodiment, the ratchet 1-4 of the ratchet mechanism can be pressed along the x-direction and will automatically spring back when there is no external force. When in contact with and pressed by the ratchet 1-4, it can rotate clockwise but cannot rotate counterclockwise, which is the principle of the ratchet mechanism, and will not be elaborated further in this embodiment. Looking along the x-axis, with the z-axis position as the starting point of the angle, a stop protrusion 1-5 is set at 67.5° on the circumference of the ratchet mechanism. The height of the stop protrusion 1-5 is half of the maximum height of the ratchet 1-4 in the x-direction. The function of the stop protrusion 1-5 is to stop, that is, when the paddle root base 8-2 moves along the positive x-direction, it will decelerate when it comes into contact with the ratchet mechanism, and will stop when it continues to rotate around the x-axis and hits the stop protrusion.

[0026] For example, in one specific embodiment, the bearing assembly 2-4 includes an axial sliding bearing and a radial rolling bearing. The inner ring of the radial rolling bearing is fixedly fitted onto the second hollow shaft 2-3, and the outer ring of the radial rolling bearing is fixedly fitted onto the axial sliding bearing. The end of the radial rolling bearing is close to the end face of the limiting block 2-5, enabling the propeller root base 8-2 to rotate about the x-axis and slide along the x-axis relative to the second hollow shaft 2-3. A second axial bearing 5 is also fitted onto the axial sliding bearing of the bearing assembly 2-4, allowing it to slide relative to the axial sliding bearing in the x-direction. One end of the second axial bearing 5 contacts the free end of the L-shaped part of the limiting structure of the second hollow shaft 2-3 away from the transmission gear 2-6, and the other end of the second axial bearing 5 contacts the end face of the propeller root base 8-2. Figure 12 As shown, one end face of the second axial bearing 5 is in contact with the first limiting structure 3-2, and the other end face of the second axial bearing 5 is in contact with the propeller root base 8-2. The main function of the second axial bearing 5 is to uniformly transmit the axial force on the actuator cylinder 3-1 to the propeller root base 8-2 through the first limiting structure 3-2, so as to limit the x-direction position of the propeller root base 8-2; and to reduce the resistance of the relative movement between the first limiting structure 3-2 and the propeller root base 8-2 around the x-axis, so as to prevent the four propeller roots of the blade assembly 8 from generating relative displacement between the propeller roots due to friction before they even contact the ratchet teeth 1-4 of the ratchet assembly.

[0027] For example, such as Figure 1 As shown, in one specific embodiment, the two clamp structures are a rear rotor root clamp 6 and a front rotor root clamp 7. The rear rotor root clamp 6 is used to receive the x-direction force transmitted by the actuator 4 and transmit it to the rotor root base 8-2. Correspondingly, as... Figure 9 As shown, two blade root clamping grooves are provided on the outer circumferential surfaces at both ends of the blade root base 8-2. The two blade root clamping grooves are a front blade root clamping groove 8-3 and a rear blade root clamping groove 8-4. The front blade root clamping groove 8-3 engages with the corresponding front blade root clamp 7, and the rear blade root clamping groove 8-4 engages with the corresponding rear blade root clamp 6. After the linear drive assembly transmits the axial force in the x-direction, the axial force is transmitted to the rear blade root clamp 6 via the actuating block 4. The axial force on the rear blade root clamp 6 is transmitted to the blade root base 8-2 until the blade root base 8-2 disengages from the limiting block 2-5. At this time, the blade root base 8-2 slides relative to the x-axis. The rear blade root clamp 6 consists of a rear blade root clamping ring 6-1, a rear blade root clamping base 6-2, and a rear blade root clamping pin 6-3. The rear propeller root clamp base 6-2 is mounted on the rotating shaft 2. The inner edge of the rear propeller root clamp base 6-2 fits against the limiting block 2-5, and the rear propeller root clamp base 6-2 can slide relative to the bearing assembly 2-4 in the x-direction. The rear propeller root clamp ring 6-1 is clamped in the rear propeller root clamp groove 8-4, constraining the blade assembly 8 within the rear propeller root clamp ring 6-1, preventing it from being thrown out due to centrifugal force. The front propeller root clamp 7 is mounted in the front propeller root clamp groove 8-3 of the blade assembly 8. The front propeller root clamp 7 consists of a front propeller root clamp ring 7-1, a front propeller root clamp outer flange 7-2, and a front propeller root clamp inner flange 7-3. The blade assembly 8 is constrained within the front propeller root clamp ring 7-1, preventing it from being thrown out due to centrifugal force. At the same time, the front propeller root clamp outer flange 7-2 and the front propeller root clamp inner flange 7-3 constrain the position of the blade assembly 8 in the x-direction. After the propeller mechanism is activated, the blade assembly 8 disengages from the limiting block 2-5. At this time, the propeller root base 8-2 slides relative to the front propeller root clamp 7, and the outer diameter of the front propeller root clamp ring 7-1 is slightly smaller than the outer diameter of the ratchet disc 1-3.

[0028] Working principle An adjustable propeller mechanism for UAVs operates in three states: before propeller shifting, during propeller shifting, and after propeller shifting.

[0029] State before rowing: as shown Figure 10As shown, the fixed shaft assembly 1 is stationary relative to the engine, and the actuator cylinder 3-1 of the actuation assembly 3 is mounted on the shaft rod 1-1 of the fixed shaft assembly 1 and rotates around the x-axis; the output torque of the engine acts on the transmission gear 2-6, and then the torque is transmitted to the actuation block 4, the rear blade root clamp 6, and the blade assembly 8 through the limit block 2-5 on the rotating shaft assembly 2, and the blade assembly 8 rotates to do work to provide thrust in the x-axis direction. The second limit structure 3-3 of the actuator cylinder 3-1 is engaged in the small limit slot 2-2 of the first hollow shaft 2-1, and the torque of the rotating shaft assembly 2 is transmitted to the actuator cylinder 3-1 of the actuation assembly 3 through the limit slot 2-2 and the second limit structure 3-3. Since the first limit structure 3-2 and the blade root base 8-2 are relatively stationary, there is no relative rotation inside the second axial bearing 5; the front blade root clamp 7 is driven to rotate by the frictional force of the contact surface of the front blade root clamp groove 8-3. Along the positive direction of the x-axis, the front end of the second limit structure 3-3, the actuation block 4, the rear blade root clamp 6, the blade root base 8-2, and the front blade root clamp 7 are sequentially attached to each other; the blade root base 8-2, the second axial bearing 5, and the first limit structure 3-2 are sequentially attached to each other. Among the above components, only the shaft rod 1-1 is stationary relative to the engine (the shaft rod 1-1 is always stationary relative to the engine regardless of whether the blade pitch adjusting mechanism is working or not), and the rotating shaft assembly 2, the actuation assembly 3, the actuation block 4, the second axial bearing 5, the rear blade root clamp 6, the front blade root clamp 7, and the blade assembly 8 all rotate around the x-axis relative to the engine.

[0030] State during blade pitch adjustment: Before the engine receives the shutdown command, the blade pitch adjusting mechanism starts to work. The operation of the blade pitch adjusting mechanism requires an external force applied in the positive direction of the x-axis through the linear drive assembly, and the external force acts on the cylindrical protrusion of the first axial bearing 3-4, at this time, the second limit structure 3-3 is gradually pushed toward the positive direction of the x-axis.

[0031] As Figure 12 shown, assuming that the moving distance is x, the fitting distance between the limit slot 8-5 of the blade assembly 8 in the x direction and the limit block 2-5 is a, the distance between the front end of the blade root base 8-2 and the tip of the ratchet 1-4 is b (a<b), the distance between the front end of the blade root base 8-2 and the top of the stop protrusion 1-5 is c (b<c), and the distance between the front end of the blade root base 8-2 and the root of the stop protrusion 1-5 is d (c>d).

[0032] When x<a: The blade root base 8-2 is not separated from the limit block 2-5. Except for the fixed shaft assembly 1 which is stationary, the translation of the actuation assembly 3, the actuation block 4, the second axial bearing 5, the rear blade root clamp 6, the front blade root clamp 7, and the blade assembly 8 along the x-axis is synchronized with the first axial bearing 3-4, and their rotation around the x-axis is synchronized with the rotating shaft assembly 2. Due to the inertia after the engine shuts down, the rotating shaft assembly 2 is still rotating around the x-axis, but there is no movement in the x direction.

[0033] When a<=x<b: At this time, the engine receives a stop command, and the paddle shifting mechanism continues to rotate due to inertia. The blade root base 8-2 disengages from the limit block 2-5. Except for the fixed shaft assembly 1 which remains stationary, the translation of the actuating assembly 3, the actuating block 4, the second axial bearing 5, the rear blade root clamp 6, the front blade root clamp 7, and the blade assembly 8 along the x-axis is synchronized with the first axial bearing 3-4. Since the actuating block 4 and the rear blade root clamp 6 are still not disengaged from the limit block 2-5, while the blade root base 8-2 has already disengaged from the limit block 2-5, the rotation of the actuating block 4 and the rear blade root clamp 6 around the x-axis is still synchronized with the rotating shaft assembly 2 except for the blade assembly 8. The second axial bearing 5 is an axial bearing, and relative motion inside the bearing has already started. The first limit structure 3-2 forms a structural limit with the limit slot 2-2, so the rotation of the actuating assembly 3 and the rotating shaft assembly 2 around the x-axis is synchronized. The components in contact with the blade assembly 8 are: the rear blade root clamp 6, the bearing assembly 2-4, the second axial bearing 5, and the front blade root clamp 7. The relative motion between the rear blade root clamp 6 and the blade root base 8-2 is frictional. The relative motion between the blade root base 8-2 and the second rotating shaft 2-3 is realized through the bearing assembly 2-4, and the relative motion between the end face of the blade root base 8-2 and the first limit structure 3-2 is realized through the second axial bearing 5, so that the blade root base 8-2 is still evenly distributed in the circumferential direction, preventing relative displacement between the four blade roots of the blade assembly 8 caused by friction before they come into contact with the ratchet assembly. There is no relative motion between the front blade root clamp 7 and the blade root base 8-2 at this stage, that is, the rotation around the x-axis is synchronized, and the front blade root clamp 7 has no torque output to the blade root base 8-2, so the torque to the blade root base 8-2 is mainly realized through the rear blade root clamp 6. At this time, the output torque of the engine is still greater than 0, and the rear blade root clamp 6 is still not disengaged from the limit block 2-5, so the blade root base 8-2 is still evenly distributed in the circumferential direction. However, due to the aerodynamic resistance of the blades, the speed of the blade root base 8-2 around the x-axis is less than or equal to the speed of the rotating shaft assembly 2 around the x-axis.

[0034] When b<=x<c: The paddle shifting mechanism continues to rotate due to inertia. But at this time, the blade root base 8-2 has come into contact with the ratchet tooth 1-4. As x increases, the inner spring of the ratchet tooth 1-4 is compressed, and the resistance effect gradually increases. When it is greater than the relative friction effect between the blade root base 8-2 and the rear blade root clamp 6, the bearing assembly 2-4, the second axial bearing 5, and the front blade root clamp 7, the circumferential relative distance of the blade root base 8-2 changes, and the rotational speed of the blade assembly 8 also begins to decrease. Since the front blade root clamp 7 has entered the fairing 1-2 at this time, and the outer diameter of the blade root clamp ring 7-1 is slightly smaller than the outer diameter of the ratchet disk 1-3, even if the three blade root bases 8-2 cannot make the front blade root clamp 7 coaxial with the rotating shaft 2 due to circumferential movement, the front blade root clamp 7 will be constrained to the axis by the fairing 1-2.

[0035] When c <= x <= d: At this point, the rotational speed of the blade assembly 8 has decreased, and the blade root base 8-2 has contacted the stop protrusion 1-5. The first blade root base 8-2 stops immediately upon contacting the stop protrusion 1-5. The second blade root base 8-2, along with the blade 8-1, will continue to rotate around x due to inertia and the friction of the rear blade root clamp 6 (the blade root base 8-2 slides relative to the rear blade root clamp 6, bearing assembly 2-4, second axial bearing 5, and front blade root clamp 7) until it contacts the first blade root base 8-2 and stops. The third and fourth blade root bases 8-2 follow the same pattern. When the fourth blade root base 8-2 contacts the third blade root base 8-2, it just engages with the ratchet on the ratchet disc 1-3, preventing reverse rotation. At this point, all four blade root bases 8-2, along with the blade 8-1, are distributed at the top. This is the state after the blade is turned. Figure 11 As shown, at this time, shaft 2 still has some rotation or has just stopped.

[0036] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A propeller control mechanism for an unmanned aerial vehicle (UAV) with adjustable propeller position, characterized in that, include: The fixed axis assembly has one end fixed to the body of the drone, and the other end extends out of the body of the drone and is connected to the fairing. The actuation component is sleeved on the fixed shaft assembly between the outer wall of the fuselage and the fairing, and can slide and rotate along the fixed shaft assembly. Two opposing limiting structures are provided on its outer periphery; the two limiting structures are a first limiting structure and a second limiting structure, and a first axial bearing is provided on the second limiting structure. A rotating shaft assembly includes a hollow shaft assembly, which is sleeved between two limiting structures of an actuating assembly. A limiting groove matching the limiting structure is opened on the hollow shaft assembly along the axial direction. An axial guide structure is located in the middle of the hollow shaft assembly, and the end of the hollow shaft assembly is connected to the output end of the engine through a transmission assembly. The blade assembly has a blade root base on its blade root. The blade root base is axially slidably connected to the hollow shaft assembly through an axial guide structure. The blade root base of the blade assembly is constrained between the clamp structure and the outer periphery of the hollow shaft assembly by two clamp structures. An actuator is sleeved on the hollow shaft assembly, and the actuator is slidably connected to the hollow shaft assembly along the axial direction through an axial guide structure; The ratchet assembly, located inside the fairing, is used to limit the rotation direction of the propeller root base and decelerate the propeller root base when it is engaged with the ratchet assembly. It is equipped with a stop structure. And a linear drive assembly, whose output end is connected to the limiting structure on the first axial bearing and the actuator assembly. It is used to drive the hollow shaft assembly to move axially, so as to push the actuator block to move through the limiting structure on the actuator assembly, so that the actuator block pushes the blade root base of the blade assembly to disengage from the axial guide structure through the clamp structure until the blade assembly speed decreases, the end face of the blade root base is pressed against the ratchet assembly in the fairing and rotates to the stop structure to stop. The hollow shaft assembly includes: The first hollow shaft has a limiting groove. And a second hollow shaft, one end of which is coaxially connected to the end of the first hollow shaft away from the limiting groove, wherein an axial guide structure is provided on the outer periphery of the end of the second hollow shaft facing the first hollow shaft, and a bearing assembly is provided on the end of the second hollow shaft away from the first hollow shaft; The axial guide structure includes: a plurality of limiting blocks evenly distributed in the circumferential direction of the second hollow shaft, one end of the limiting block is used to cooperate with the limiting groove provided on the propeller root base, and the other end of the limiting block is used to slide to connect with the guide groove provided on the inner wall of the mounting hole in the middle of the actuating block.

2. The UAV propeller control mechanism with adjustable propeller position according to claim 1, characterized in that, The ratchet assembly includes a ratchet disc, which is fitted and fixed inside the fairing, and has multiple ratchet teeth evenly distributed on one side facing the propeller root base end face.

3. The UAV propeller control mechanism with adjustable propeller position according to claim 1, characterized in that, The ratchet teeth are protrusions that gradually increase in height in the direction of blade rotation.

4. The UAV propeller control mechanism with adjustable propeller position according to claim 3, characterized in that, The stop structure includes a stop protrusion disposed between two adjacent ratchet teeth, and the height of the stop protrusion is half the maximum height of the ratchet teeth.

5. The UAV propeller control mechanism with adjustable propeller position according to claim 1, characterized in that, A transmission gear is coaxially mounted on the end of the first hollow shaft opposite to the end of the second hollow shaft, and the transmission gear is connected to the output gear at the output end of the engine.

6. The adjustable propeller position unmanned aerial vehicle propeller control mechanism according to claim 5, characterized in that, The actuation assembly includes an actuation cylinder, wherein the limiting structure includes multiple L-shaped members, which are evenly distributed on the outer peripheral surface near the end of the actuation cylinder. One end of the L-shaped member is fixed to the outer peripheral surface of the end of the actuation cylinder, and the other end of the L-shaped member is a free end. The free ends of the L-shaped members of the two limiting structures are opposite to each other.

7. The UAV propeller control mechanism with adjustable propeller position according to claim 6, characterized in that, The bearing assembly includes: a radial rolling bearing, the inner ring of which is fixedly fitted onto the second hollow shaft, and an axial sliding bearing, the outer ring of which is fixedly fitted onto the outer face of the locating block.

8. The UAV propeller control mechanism with adjustable propeller position according to claim 7, characterized in that, It also includes: a second axial bearing, which is sleeved on the axial sliding bearing of the bearing assembly, one end of which is used to contact the free end of the L-shaped part of the limiting structure of the second hollow shaft away from the transmission gear, and the other end of which is used to contact the end face of the propeller root base.

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