59 results about "Folding propeller" patented technology

A combination powered parachute and motorcycle modifies an initially conventional motorcycle with the addition of various flight components to provide sustained flight for the machine. A peripheral and overhead safety structure is installed upon the motorcycle, with a second flight engine, propeller, folding propeller guard, and fuel system also installed. The flight engine and all of its systems are completely independent of the conventional motorcycle engine used for surface propulsion. A set of laterally disposed stabilizer wheels is also provided for transition from ground to flight and from flight to ground operation. Lift is provided by a folding parafoil device of either the ram air inflated or partially pneumatically inflated type. For flight operations, the lateral wheels are lowered and extended, the folding propeller guard is extended, and the parafoil is deployed behind the motorcycle, with the parafoil lifting conventionally upon attaining flight speed.

The invention relates to a foldable propeller. The foldable propeller is provided with a left paddle blade, a right paddle blade, an upper paddle cover and a lower paddle cover, wherein mounting ends are respectively mounted on the left paddle blade and the right paddle blade, the mounting ends of the left paddle blade and the right paddle blade are clamped between the upper paddle cover and the lower paddle cover, the mounting end of the left paddle blade is connected with the upper paddle cover and the lower paddle cover in a hinge manner, the mounting end of the right paddle blade is connected with the upper paddle cover and the lower paddle cover in a hinge manner, horizontal connecting rods are respectively arranged at the middle parts of the upper paddle cover and the lower paddle cover, and motor shaft mounting holes are formed in the middle parts of the horizontal connecting rods. The foldable propeller has the advantage of low manufacturing cost of moulds. The paddle blades of the foldable propeller can be folded, a motor shaft of a motor for driving the propeller is not bent and damaged under the impact of the left paddle blade and the right paddle blade, and the maintenance cost generated by the damage of other important parts is reduced. Simultaneously, the folded propeller can be used for protecting the left paddle blade and the right paddle blade well during carrying.

A vertical take-off and loading (VTOL) rotary aircraft or helicopter has eight propellers in a quad propeller arm configuration where each propeller arm has two counter-rotating propellers. Folding propeller arms are designed to allow storage in a single car sized garage. Each propeller may be powered by a three-phase alternating current motor. The main power plant for the aircraft is a gas combustion engine that generates electricity. If the gas engine fails, a battery backup system will safely bring the aircraft down for a controlled landing. The direct current bus is redundant in that even with a gas combustion engine failure the direct current bus battery pack will safely bring down the aircraft. Various embodiments of this invention may also include a landing gear crumple zone designed to soften a hard landing.

The invention discloses a folding propeller with limiting structures and belongs to the technical field of aviation devices. The folding propeller with the limiting structures comprises a propeller clamp and propeller blades, wherein the propeller blades are rotationally connected with two sides of the propeller clamp, propeller blade limiting structures are arranged on the folding propeller, U-shaped openings are formed in tail ends of two sides of the propeller clamp in the horizontal direction, roots of the propeller blades are rotationally arranged in the U-shaped openings through a vertical shaft, and each propeller blade limiting structure is arranged between the propeller clamp and the corresponding propeller blade. In the transportation process, the folding propeller can keep a folding state reliably, various problems caused by swinging of the propeller blades in the transportation process are prevented, the folding propeller can be in an unfolding state reliably during flying through the limiting structure as is required, smooth take-off is guaranteed, and the folding propeller with the limiting structures has a good technical effect.

A vertical take-off and landing aircraft or drone that has at least two tilting propellers mounted in front of the center of gravity of the wing. These tilting propeller are actively controlled and are capable of providing pitch, roll and yaw control throughout the flight envelop. This method of control can be applied to tilt wing or teal sitter aircraft, conventional or flying wing as well as other wing configuration for example box wing. In hovering flight the wing would be in the vertical position. The tilting propeller would provide pitch and yaw control. Roll control would be provided by differential thrust of the propellers. As the aircraft transitions to forward flight pitch control would be provided by tilting propeller. While yaw and roll control would be provided by a combination of tilting propellers and differential thrust. Upon complete transition to forward flight pitch and roll can be provided by telting propeller and or by a combination of aerodynamic control surfaces for example elevator ailerons or elevons depending on the wing configuration. While differential thrust could provide yaw and or rudder. Also throughout the flight envelop control surfaces can provide supplement control. The same process would be completed to transition to hovering flight.

The invention discloses a flying robot with variable sweep angle launch tandem wings and aims to solve the problem that neither two front folding wings nor two rear folding wings of an existing launch flying robot can be unfolded respectively, so that moving attitude control of the flying robot is limited. The flying robot comprises a folding propeller, a fuselage, a left rear wing, a right rear wing, a left front wing, a right front wing, two vertical tails, two vertical tail pin shafts and four rotary hinges, wherein the folding propeller is installed on the head of the fuselage, the left front wing and the right front wing are symmetrically arranged on the two sides of the front end of the fuselage, the left rear wing and the right rear wing are symmetrically arranged on the two sides of the rear end of the fuselage, the left front wing, the right front wing, the left rear wing and the right rear wing are hinged to the corresponding rotary hinges respectively, each rotary hinge is connected with a corresponding helm gear in the fuselage, and the two vertical tails are symmetrically arranged on the two sides of the tail end of the fuselage and installed on the upper surface of the tail portion of the fuselage through torsional springs. The flying robot is used for attitude control.

The invention discloses a portable inflatable water mobile platform. The portable inflatable water mobile platform comprises a bearing platform and air bags connected with the bearing platform and used for providing buoyancy. A propelling mechanism is hinged to or detachably connected with the bearing platform. The bearing platform is further provided with a first cavity. Under a work state, the propelling mechanism extends into water. Under a storage state, the propelling mechanism is stored in the first cavity. The portable inflatable water mobile platform is simple in structure and easy to manufacture, switching between the work state and the storage state is very convenient, maneuverability is good, and the water mobile platform is easy to expand and splice, is very good in portability and can be applicable to fishing, water entertainment, water sports, water traveling, cargo carrying, flood fight, disaster relief and other purposes. The portable inflatable water mobile platform can be safely, reliably and conveniently used with the help of various function expansion elements such as batteries, foldable propellers, automatic inflation systems, control systems, mobile phone APPs and other subsystems. The portable inflatable water mobile platform overcomes defects of associated traditional equipment, and good experience is provided for users.

The invention relates to a folding propeller for an above-water platform. The folding propeller comprises a beam, a fixing base, a fixing block, a motor rod and a propeller motor. The beam is positioned in the rear of the above-water platform, a fixing mechanism is arranged on the beam and can be connected with the fixing block, the fixing base is positioned on the inner side face of the beam and is connected with the fixing block through an overturning arm, the motor rod is connected to the fixing block through a movable rotating shaft and comprises an upper arm and a lower arm, a steering motor is arranged in the upper arm, the double-blade propeller motor is mounted at the tail end of the motor rod, and the lower arm is rotated by the steering motor, so that the direction of the propeller motor can be adjusted. When in a storage state, the folding propeller is folded to be stored in a chamber of the above-water platform; when in a working state, the folding propeller can be powered on to be in operation after the fixing block is overturned on the beam to be connected with the fixing mechanism, then the motor rod is overturned to be downward vertically and the propeller motor is adjusted to face the rear by the steering motor. The folding propeller for the above-water platform is easy in folding storage, convenient to operate, high in safety and particularly applicable to power-driven propelling of portable above-water platforms.

A folding propeller-hub assembly for VTOL aircraft provides two modes of operation, a vertical mode with unfolded propeller blades and a horizontal mode with propeller blades positionable in both an aerodynamic folded position and an active unfolded position. The propeller-hub assembly includes a plurality of propeller blades, a bedplate operably associated with a propeller-hub to fold or respectively unfold the propeller blades, the motor arranged between the propeller-hub and a rotating plate, a push rod positioned in the axis of the propeller rotation along the propeller-hub assembly. The bedplate is operably associated with a device which connects with the spinner bottom of the spinner to rotate the propeller blades. A restraint plate by virtue of the push rod is operably associated with the propeller blades to rotate each propeller blade about a propeller blade pin axis.

The invention provides a folding rotor wing of a coaxial unmanned helicopter. The folding rotor wing comprises a variable-pitch propeller hub, a folding propeller clamp assembly, blades, a torsional spring and a centrifugal pendulum limiter, and the folding propeller clamp assembly is rotationally connected to the end portion of the variable-pitch propeller hub through a flapping bolt and a flapping bearing; the blades are connected to the end portion of the folding paddle clamp assembly; the flapping bolt is sleeved with the torsional spring, the upper torsional arm of the torsional spring stretches into the through hole of the variable-pitch propeller hub, and the lower torsional arm of the torsional spring abuts against the bottom of the folding propeller clamp assembly; and the centrifugal pendulum limiter is movably connected to the variable-pitch propeller hub through a rotating shaft, and after the folding propeller clamp assembly is unfolded, the centrifugal pendulum limiter isconnected to the end portion of the folding propeller clamp assembly in a clamped mode. The rotor wing avoids the blade beating phenomenon, the operation stability is high, the safety is high, and the installation is convenient.

A folding propeller for a boat, e.g., for a sailboat or a multihull yacht, and a method for installing and / or adjusting such a folding propeller, where said folding propeller has a hub for directly or indirectly fastening at a driveshaft connected to a motor, where said folding propeller further has at least two individual blades, where each of said blades has a root arranged to pivot around a pivot pin at said hub to be either in a first, operative position, where the blades are pointing mainly in a radial direction, and in a second, inoperative position, where the blades are pointing mainly in an axial direction, where said hub has one or more cut outs for said blades roots and further has a first set of holes for installing said pivot pins and a second set of holes for installing a locking device for engagement with said pivot pins.

The invention relates to a propeller strut device of a floating crane of a large floating crane. The propeller strut device of the floating crane is characterized in that one end of a turntable is hinged with the bottom end of a folding rear draw bar composed of an A pulling plate, a connecting rack, a pin shaft and a B pulling plate; the top end of the folding rear draw bar is hinged with a connecting plate; the included angle of the folding rear draw bar and the turntable is beta; a propeller strut retracting device composed of a bracket, a movable pulley block, a wire rope, a fixed pulley block and a winding mechanism is assembled at the other end of the turntable; and located falling and located ascending of the folded propeller strut are achieved by contracting and winding of the wire rope by the winding mechanism. The propeller strut device not only has reasonable design, and simple and practical structure, but also can put down and lift the propeller strut in the manners of folding the propeller strut rear draw bar and winding the wire rope together with the winding mechanism, achieves clear and smooth navigation of the large floating crane in coastal water or inland river, and has the characteristics that the propeller strut device is high in efficiency, simple to operate, convenient to maintain, small in investment, low in cost, safe to operate, convenient to use, and the like.

The invention relates to unmanned aerial vehicles, in particular to a tilting type vertical taking-off and landing unmanned aerial vehicle. The tilting type vertical taking-off and landing unmanned aerial vehicle comprises a task warehouse and a vehicle body. The task warehouse is integrally connected with the vehicle body. A flight control equipment cabin is arranged at the position, close to thetask warehouse, of the vehicle body. Wings are arranged on the positions, located on the left and right sides of the flight control equipment cabin, of the vehicle body. The two wings are symmetrically arranged. Auxiliary wings are arranged on the wings. Tail wings are arranged on the tail part of the vehicle body. Steering rudders are arranged at the tail wings. The two steering rudders are symmetrically arranged. Fixing wings are arranged at the positions, close to the vehicle body, of the wings. The unmanned aerial vehicle requires no external assistance to take off and land, and thereforeelectric power loss is reduced when the unmanned aerial vehicle is in the air. Resistance due to engine failure to tilt is reduced. A screw propeller is folded backwards after tilting of the tiltingengine by folding propellers, and therefore resistance caused by a conventional non-folding propeller is greatly reduced.

A vertical take-off and loading (VTOL) rotary aircraft or helicopter has eight propellers in a quad propeller arm configuration where each propeller arm has two counter-rotating propellers. Folding propeller arms are designed to allow storage in a single car sized garage. Each propeller may be powered by a three-phase alternating current motor. The main power plant for the aircraft is a gas combustion engine that generates electricity. If the gas engine fails, a battery backup system will safely bring the aircraft down for a controlled landing. The direct current bus is redundant in that even with a gas combustion engine failure the direct current bus battery pack will safely bring down the aircraft. Various embodiments of this invention may also include a landing gear crumple zone designed to soften a hard landing.

The invention discloses a folding propeller, a power device and an unmanned aerial vehicle. The folding propeller comprises a propeller seat and propeller blades mounted on the propeller seat, and further comprises pin shafts and an elastic piece; one ends of the propeller blades are connected with the propeller seat through the pin shafts in a hinged mode; and the two ends of the elastic piece act on the propeller seat and the propeller blades correspondingly. The folding propeller is used for the power device, the power device is used for the unmanned aerial vehicle, according to the structural design of the propeller, the propeller blades can be retracted automatically after the rotating speed of the propeller is decreased, in this way, the safety of the propeller during landing of theunmanned aerial vehicle is facilitated, and meanwhile, retracting of the propeller blades does not depend on external energy input; and meanwhile, the propeller is simple in structure, small in mass and high in reliability.

The invention discloses a high-altitude long-endurance unmanned aerial vehicle with foldable telescopic wings, and relates to the technical field of aviation. The problems that an existing high-altitude long-endurance unmanned aerial vehicle occupies too large space during transportation and storage due to the fact that the wingspan is too large, the maintenance cost is high, and rapid deployment is difficult are solved. The unmanned aerial vehicle comprises a vehicle body, two front folding wings, two rear folding wings, two front telescopic wings, two rear telescopic wings, two folding empennages, two folding propeller blades, a plurality of folding mechanisms and a plurality of telescopic mechanisms, the front folding wings are symmetrically arranged on the two sides of the front end of the abdomen of the vehicle body respectively, and the front telescopic wings are inserted into the outer side ends of the front folding wings; the rear folding wings are symmetrically arranged on the two sides of the rear end of the top of the fuselage respectively, the rear telescopic wings are inserted into the outer side ends of the rear folding wings, the folding empennages are symmetrically arranged on the two sides of the rear portion of the fuselage respectively, and the two folding propeller blades are symmetrically arranged at the tail of the fuselage. The invention is used for the high-altitude long-endurance unmanned aerial vehicle.

The invention relates to flight principle technology of unmanned aerial vehicles. An in-series coaxial twin-propeller tailstock-type vertical taking-off and landing unmanned aerial vehicle includes: a front-pulling power system, a main body, a tube sleeve propeller back-pushing power system, a tail tube, a cross-shaped tailstock, and a support leg damping system. The main body internally includes a battery cabin, a mission payload cabin, and a flight control system cabin; when the aerial vehicle is taken-off, the vehicle is support by the support leg damping system. The front-pulling propeller and the back-pushing tube sleeve propeller rotate to generate taken-off power, and meanwhile, the reversal torsional moments due to the propellers are reduced. Flight control manipulates ailerons and a control surface of the cross-shaped tailstock so that the ailerons and the cross-shaped tailstock generate steerage due to slip flow brought by fold propellers, thereby correcting and controlling the attitude of the aerial vehicle and ensuring flight of the aerial vehicle. During vertical landing, the support leg damping system works. The unmanned aerial vehicle has simple and reliable flight principle, and compared with inclined disc coaxial twin-propeller structure, the unmanned aerial vehicle is simpler in control principle.

The invention belongs to the field of underwater robots, and particularly relates to a folding propeller device for a hybrid-drive underwater robot. The device includes an after-body flow guide cover, a motor, a coupler, a propeller shaft, a propeller hub and propeller blades; the motor is installed in the after-body flow guide cover, the output end of the motor is connected with one end of the propeller shaft through the coupler and drives the propeller shaft to rotate, and the other end of the propeller shaft penetrates through the after-body flow guide cover and is connected with the propeller hub.; a plurality of propeller blade shafts are installed on the propeller hub, the propeller blade shafts are rotatably connected with the propeller blades, each propeller blade shaft is provided with a torsion spring in a sleeving mode, and the two ends of each torsion spring are connected with the propeller hub and the corresponding propeller blade respectively; the propeller blades are driven by the propeller blade shafts to rotate along with the propeller hub and are spread through centrifugal force, push force is thus produced, and the spread and rotating-stopping propeller blades returns to the original position through the torsion springs. The device has the advantages of being high in reliability, compact in mechanical structure, simple in motion mode, light, low in cost, safe in transportation, easy to assemble and maintain and the like.

The invention provides a folding propeller control method and device and folding propeller control equipment. The method comprises the steps that before a drone takes off, when at least two blades ofa folding propeller is folded, a controller sends a driving signal for controlling the folding propeller to unfold to a motor, wherein the driving signal is used for driving the motor to speed up forrunning; when it is monitored that the rotating speed of the motor reaches maximum propeller spinning speed and the folding propeller is in a folded working state, the motor is driven to slow down forrunning; the maximum propeller spinning speed is smaller than a take-off rotating speed of the drone; the processes of driving the motor to speed up for running and driving the motor to slow down forrunning are executed repeatedly until it is monitored that at least two blades of the folding propeller are in a completely-unfolded working state. According to the folding propeller control method,device and equipment, by controlling the motor before the drone takes off, the folding propeller is automatically unfolded before take-off, and the rollover risk caused by direct take-off of the droneunder the situation that the propeller is folded is avoided.

The invention belongs to the technical field of air vehicles, and particularly relates to a limiting device for front flying propellers of a full-electric vertical take-off and landing fixed-wing unmanned aerial vehicle. The limiting device comprises a steering engine, a rocker arm, a cam and a remote control. The rocker arm is installed on the steering engine, the rocker arm is driven by the steering engine to rotate, and the cam is fixedly installed on the tail portion of a motor rotating shaft of the unmanned aerial vehicle. The rocker arm is in contact with the cam during rotating, so thatthe cam drives the propellers to rotate to the horizontal position through the motor rotating shaft of the unmanned aerial vehicle. The remote control is connected with the steering engine through wireless network. The limiting device realizes limiting the front flying propellers of the full-electric vertical take-off and landing fixed-wing unmanned aerial vehicle to be near the horizontal position at the landing stage, and avoids the use of folding propellers, landing gear and other components to reduce the aerodynamic performance of the aircraft; and the limiting device realizes the self-locking of the rocker arm through the design of the top face of the rocker arm, so that the rotation of the propellers cannot cause the rocker arm to rotate when the rocker arm is in place.

A utility helicopter generally has two propellers, the bigger propeller provides a rising force, and the smaller propeller provides a forward propulsive force. The invention adopts three propellers and is called a parachute-type helicopter, wherein, two of the three propellers are the same with a utility helicopter; the bigger propeller provides a rising force; and the smaller propeller provides a forward propulsive force. A parachute-shaped truncated cone is mounted at the bottom part of the parachute-type helicopter; the third propeller is mounted at the top of the truncated cone; the rotation direction of the third propeller is opposite to that of the bigger propeller which provides a rising force, so as to excellently keep the balance of the parachute-type helicopter; the shape and the function of the propeller on top of the truncated cone are the same with a ventilating fan, and the propeller can absorb airflow under the truncated cone; through high speed revolution, abundant air is insufflated into a container of the truncated cone to form a pressure which rushes out of a small hole at the bottom part of the truncated cone in high speed, and generates an upward propulsive force acting on the parachute-type helicopter; and both of the propellers mounted on top of the truncated cone and the big propellers mounted on top of the parachute-type helicopter can produce upward ascensional force, so that the working efficiency of a motor can be improved. The invention changes the foundational structure of a helicopter, improves the efficiency of a propeller, and enables a helicopter to fly higher and farther with the same energy.

The invention discloses a submarine revolving flapping wing propeller. The submarine revolving flapping wing propeller comprises a submarine body and a revolving flapping wing propeller body installed on the submarine body. The revolving flapping wing propeller body comprises a power motor, a direction control motor, a shaft head gear of the direction control motor, a spindle fixing base, a direction control protruding block, flapping wing paddles with flapping wing paddle shafts, a propeller spindle, a spindle head cover, idler wheels fixed to the flapping wing paddle shafts and balls arranged on the flapping wing paddle shafts in a sleeved mode. The power motor drives the flapping wing paddles to rotate when rotating, and the idler wheels on the flapping wing paddle shafts can roll on the face of the direction control protruding block; when the idler wheels roll to the protruding portion of the face of the direction control protruding block, the flapping wing paddles enter a flapping propelling state from a feathering revolving state to carry out propelling work, and otherwise, the flapping wing paddles are in a feathering revolving state. According to the submarine revolving flapping wing propeller, because the revolving flapping wing propeller body can rotate by 360 degrees from the perspective of propelling direction, a hull of diving equipment can be easily controlled to move upwards, downwards, forwards and backwards; the submarine revolving flapping wing propeller has the advantages of being flexible in operation, efficient and low in noise.

The invention specifically relates to a split type folding propeller protection frame and an application method thereof, belonging to the technical field of unmanned aerial vehicles. The propeller protection frame comprises a protection frame base and branch arms, wherein one end of the protection frame base is connected with the end part of an arm of an unmanned aerial vehicle via a spindle, so the protection frame base can turn over around the arm relative to the extending direction of the arm; the other end of the protection frame base is connected with the symmetrically arranged branch arms via spindles; and the branch arms can rotate around the spindles in a range from an unfolding position to a folding position, and the unfolding position and the folding position are parallel to theprotection frame base. According to the propeller protection frame of the invention, the arm is connected with the protection frame base and the branch arms via the spindles, so the protection frame base and the branch arms can respectively rotate around the spindles, and the propeller protection frame capable of protecting a propeller is formed when the protection frame base and the branch arms are unfolded; after folding and storage, the propeller protection frame fits with the arm, so the space occupied by the protection frame relative to the integral unmanned aerial vehicle can be effectively reduced; and the propeller protection frame and the arm are connected by a detachable structure, so the propeller protection frame can be dismounted when not needed, and the protection frame willnot be lost when fixed on the arm.

A quick release propeller for model airplanes is disclosed including two or more blades mounted to a hub. For each blade, the hub includes a slot and a shoulder. Each blade includes a base portion having pins which slide into the slot in the hub. The slots are curved which prevents the blades from being removed unless they are rotated at predefined threshold angle with respect to the hub.

The invention relates to a folding-wing unmanned aerial vehicle. The folding-wing unmanned aerial vehicle comprises a vehicle body, a front straight wing, a rear straight wing, a folding vertical finwhich is installed on the afterbody of the vehicle body, and a folding propeller assembly at the rear end of the vehicle body. One of the front straight wing and the rear straight wing is installed onthe top face of the vehicle body, the other one is installed on the bottom face of the vehicle body, and the front straight wing and the rear straight wing can be folded with the vehicle body as thecenter. According to the folding-wing unmanned aerial vehicle, in the unfolding process, the front straight wing and the rear straight wing can be symmetrically unfolded on the left and right sides with the vehicle body as the center, so that in the unfolding process, no difference exists between the balance forces of the front straight wing and the rear straight wing to the unmanned aerial vehicle body on the two sides, rotation of the vehicle body is not easily caused, the stability of the unmanned aerial vehicle is improved, and then the launching success rate of the unmanned aerial vehicleis improved.

The invention relates to a contra-rotating propeller blade structure, in particular to a horizontally folded contra-rotating propeller which is foldable and used for a structure of a cylindrical emission type unmanned aerial vehicle. A first propeller comprises a first propeller hub, a first propeller blade, a second propeller blade and a first folding rotating shaft; and a second propeller comprises a second propeller hub, a third propeller blade, a fourth propeller blade and a second folding rotating shaft. Through adoption of the technical scheme, the propeller blades are horizontal three-fold propeller blades and rotate around fixed rotating shafts; and the rotation directions of the two pairs of propeller blades are reverse to each other so that the self-balancing of reverse torque is realized. Through the engaged rotations of two pairs of symmetric bevel gears, synchronized and reverse rotation is realized. As limiting devices are arranged on the folded propeller blades, the propeller blades can be jammed in one way when being unfolded to reach a collinear position of the two propeller blades, and therefore, the stability in rotation is ensured. The complexity degree of the mechanism is reduced and the reliability of the mechanism is enhanced. As the horizontally folded contra-rotating propeller is naturally unfolded by means of centrifugal force in rotation and driven by the two pairs of symmetric engaged bevel gears, strict synchronized and reverse rotation is realized.

The invention discloses a power assembly and a rotorcraft. The power assembly comprises a motor, a propeller connected with the motor and a limit unit, wherein the motor is mounted on a motor base ofa rotor UAV (unmanned aerial vehicle), the limit unit is arranged on the motor base or an arm or a foot rest of the rotor UAV, the propeller has an unfolding position and a folding position, and whenthe propeller is in the folding position, the limit unit can be connected with the folded propeller and limit the propeller in the folding position; when the propeller is in the unfolding position, the limit unit is separated from the propeller. By means of the limit unit, the propeller can be limited in the folding position and cannot rotate freely when the rotorcraft is folded for packaging, andpackaging is facilitated; the limit unit is arranged on the motor base, the arm or the foot rest, so that the limit unit cannot be separated from the rotor UAV when not in use and can be effectivelyprevented from getting lost.

The invention discloses a coaxial propeller folding mechanism, a coaxial unmanned aerial vehicle and a propeller unfolding and folding control method. The technical problem that in a coaxial unmanned aerial vehicle in the prior art, a folding propeller mechanism needs to be manually installed or unfolded by ground personnel is solved. The coaxial propeller folding mechanism comprises more than two groups of rotating units which are sequentially arranged from top to bottom, and the more than two groups of rotating units are coaxially arranged; each rotating unit comprises a rotating driving device, a propeller hub, a propeller clamp and a rotor wing blade, the rotating center of the propeller hub is fixedly connected with the torque output end of the rotating driving device, and the rotor wing blade is hinged to the free end of the propeller hub through the propeller clamp; and in the more than two groups of rotating units, the length from the rotating center to the free end of the propeller hub is sequentially reduced from top to bottom. The rotor blade can be automatically and repeatedly opened and closed, and after the rotor blade positioned at the upper part is folded, a space for folding and storing the rotor blade at the lower part can be reserved, so that the two rotors are ensured not to interfere with each other.

The invention discloses a folding propeller device. The folding propeller device comprises a base assembly, a steering shaft, a steering arm, a steering cylinder, a boom cylinder, a transmission assembly, a cage assembly, a propeller assembly, a transmission shaft, hinge pins, a bolt and a control system. The base assembly is internally provided with plane bearings, and a mounting hole and a rotating arm are arranged in the base assembly. The lower end of the steering shaft is integrally connected with the transmission assembly, and the steering arm is assembled at the upper end of the steering shaft in an orderly mode. The telescopic end of the steering cylinder is connected with the steering arm, and the telescopic end of the boom cylinder is connected with the rotating arm. The spheralcage assembly is fixedly installed on an input shaft of the transmission assembly, and the propeller assembly is fixedly installed on an output shaft of the transmission assembly. The folding propeller device is scientific in design, compact in structure, reliable in performance, convenient to assemble and disassemble and low in cost, the folding propeller device is mounted on a rear bottom plateof a vehicle in a folding mode, and can provide ideal power and reliable steering for the vehicle to float across the water surface.