A coaxial unmanned helicopter with folding rotor

Abstract

The present application provides a coaxial unmanned helicopter folding rotor, comprising: a variable pitch hub, a folding blade clamp assembly, blades, a torsion spring and a centrifugal swing limiter, wherein the folding blade clamp assembly is rotatably connected to the end of the variable pitch hub through a swing bolt and a swing bearing; the blade is connected to the end of the folding blade clamp assembly; the torsion spring is sleeved on the swing bolt, the upper torsion arm of the torsion spring extends into the through hole of the variable pitch hub, and the lower torsion arm of the torsion spring abuts against the bottom of the folding blade clamp assembly; the centrifugal swing limiter is movably connected to the variable pitch hub through a rotating shaft, and when the folding blade clamp assembly is unfolded, it is clamped to the end of the folding blade clamp assembly. The rotor of the present application will not have a flapping phenomenon, has high operating stability, high safety, and is easy to install.

Description

Technical Field

[0001] The present application relates to the technical field of unmanned aerial vehicles, and in particular to a coaxial unmanned helicopter with folding rotors. Background Art

[0002] At present, with the continuous development of science and technology, drones have been widely used. Drones are unmanned aircraft controlled by radio remote control equipment and self-contained program control devices. Drones provide lift to drones through the high-speed rotation of the rotors. Existing similar foldable blade drone rotors use flapping hinges to achieve rotor blade folding, and the blades flap up and down perpendicular to the rotor plane. Although the above rotors can meet basic functions, they have the following shortcomings:

[0003] 1) During the deployment process, the blades may swing up uncontrollably and easily hit the propeller due to uneven rotation speed;

[0004] 2) The current deployment mechanism mainly relies on centrifugal force to unfold, which is only suitable for rotors with smaller diameters. For rotors with larger diameters, this deployment method has a low success rate;

[0005] 3) Since there is no motion-limiting design in the existing folding structure, there is a risk of the helicopter's propellers flapping when encountering strong winds during flight. Summary of the invention

[0006] The purpose of the present application is to provide a coaxial unmanned helicopter folding rotor, which will not have a flapping phenomenon, has high operating stability, high safety, and is easy to install.

[0007] To achieve the above-mentioned purpose, the present application provides a coaxial unmanned helicopter folding rotor, comprising: a hub, a variable pitch hub, a folding propeller clamp assembly, blades, a torsion spring and a centrifugal pendulum limiter, wherein the folding propeller clamp assembly is rotatably connected to the end of the variable pitch hub through a swinging bolt and a swinging bearing; the blade is connected to the end of the folding propeller clamp assembly; the torsion spring is sleeved on the swinging bolt, the upper torsion arm of the torsion spring extends into the through hole of the variable pitch hub, and the lower torsion arm of the torsion spring abuts against the bottom of the folding propeller clamp assembly; the centrifugal pendulum limiter is movably connected to the variable pitch hub through a rotating shaft, and when the folding propeller clamp assembly is unfolded, it is clamped at the tail of the folding propeller clamp assembly.

[0008] As above, wherein the centrifugal pendulum limiter is symmetrically connected to both sides of the variable pitch hub.

[0009] As above, wherein the folding paddle clamp assembly has a limiting mechanism at one end and a connecting portion for connecting a paddle blade at the other end, when the folding paddle clamp assembly is in an unfolded state; the centrifugal pendulum limiter is clamped in the limiting mechanism, and when the folding paddle clamp assembly is in a folded state, the centrifugal pendulum limiter is separated from the limiting mechanism.

[0010] As above, wherein the limiting mechanism includes an upper limit moveable protrusion and a lower limit moveable protrusion which are spaced apart from each other, and a limiting groove is formed between the upper limit moveable protrusion and the lower limit moveable protrusion; the centrifugal pendulum limiter includes a reverse stop claw, and when the folding paddle clamp assembly is in the unfolded state, the reverse stop claw is clamped in the limiting groove, the upper limit moveable protrusion is located above the centrifugal pendulum limiter, and the lower limit moveable protrusions are respectively located at the bottom of the reverse stop claws.

[0011] As above, wherein one side of the lower limit block close to the limit groove is a plane, and the other side is an arc transition surface; when the reverse stop claw is clamped in the limit groove, the side of the reverse stop claw in contact with the lower limit block is a plane.

[0012] As above, wherein one end of the centrifugal pendulum limiter close to the upper limit stop is an arc portion, and the other end is a protruding rod.

[0013] When the folding paddle clamp assembly is in an unfolded state, the lower limit projection is clamped in a groove between the extension rod and the reverse stop claw.

[0014] As above, wherein the variable pitch hub is rotatably connected to the hub center piece.

[0015] A coaxial unmanned helicopter folding rotor also includes a variable pitch rocker arm, which is connected to the variable pitch hub through a variable pitch hub assembly.

[0016] As above, wherein the swing bolt is fixedly connected to one end of the variable pitch hub away from the hub, and the two ends of the folding blade clamp assembly are respectively mounted on the two ends of the swing bolt and are rotatably connected to the swing bolt through a swing bearing.

[0017] The beneficial effects achieved by this application are as follows:

[0018] (1) The present application adopts a torsion spring and a centrifugal pendulum limiter as dual insurances to limit the limiting angle of the folding propeller clamp assembly, that is, the angle at which the folding propeller clamp assembly can be displaced upward or downward relative to the variable pitch propeller hub. When the speed of the motor connected to the propeller hub is uneven or the helicopter encounters strong winds during flight, the present application can prevent the upper and lower blades from being displaced upward or downward by too large an angle, causing the phenomenon of flapping propellers, thereby improving the stability and safety of the unmanned helicopter's flight.

[0019] (2) The limiting angle of the present application can be changed according to actual conditions, effectively preventing the upper and lower blades of the rotor from hitting each other during deployment and flight, thereby improving the flight stability of the unmanned helicopter.

[0020] (3) The torsion spring of the present application provides power for the initial deployment of the blades, which is not only beneficial to the deployment of small-diameter rotors, but also beneficial to the deployment of large-diameter rotors.

[0021] (4) This application does not require excessive weight increase while meeting the requirements and functions of the basic design, and is easy to maintain and process. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present application. For those skilled in the art, other drawings can also be obtained based on these drawings.

[0023] Figure 1 The present invention is a schematic diagram of the three-dimensional structure of a coaxial unmanned helicopter folding rotor.

[0024] Figure 2 The present invention is a cross-sectional view of a coaxial unmanned helicopter with its folded rotors in an unfolded state.

[0025] Figure 3 The present invention is a cross-sectional view of a coaxial unmanned helicopter with foldable rotors in a folded state.

[0026] Figure 4 It is a partial schematic diagram of a coaxial unmanned helicopter with foldable rotors in a folded state according to the present invention.

[0027] Figure 5 The present invention is a schematic diagram of the position between a centrifugal pendulum limiter and a folding blade clamp assembly of a coaxial unmanned helicopter with a folding rotor in a folded state.

[0028] Figure 6 The present invention is a schematic diagram of the position between a centrifugal pendulum limiter and a folding blade clamp assembly of a coaxial unmanned helicopter with its folding rotors deployed.

[0029] Figure 7 It is a schematic diagram of a state in which a folding blade clamp assembly of a coaxial unmanned helicopter is in a folding rotor unfolded state according to the present invention and is in a lower limit position.

[0030] Figure 8 It is a schematic diagram of a state in which a folding blade clamp assembly of a coaxial unmanned helicopter is in an upper limit position when the folding rotor of the coaxial unmanned helicopter is in an unfolded state according to the present invention.

[0031] Figure markings: 1-hub central part; 2-pitch hub; 3-folding blade clamp assembly; 4-torsion spring; 5-centrifugal pendulum limiter; 6-swinging bolt; 7-swinging bearing; 8-pitch rocker arm; 9-pitch hub assembly; 21-through hole; 22-opening groove; 31-limiting mechanism; 32-connecting part; 33-blade mounting groove; 34-connecting side plate; 41-upper torsion arm; 42-lower torsion arm; 51-reverse stop claw; 52-extending rod; 53-arc portion; 311-upper limit protrusion; 312-lower limit protrusion; 313-limiting groove. DETAILED DESCRIPTION

[0032] The following is a clear and complete description of the technical solutions in the embodiments of the present application in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present application.

[0033] like Figure 1 As shown, a coaxial unmanned helicopter folding rotor comprises: a hub central piece 1, a pitch hub 2, a folding blade clamp assembly 3, blades (not shown in the figure), a torsion spring 4 and a centrifugal pendulum limiter 5, wherein the pitch hub 2 is symmetrically mounted at both ends of the hub central piece 1; the folding blade clamp assembly 3 is rotatably connected to the end of the pitch hub 2 through a swinging bolt 6 and a swinging bearing 7; the blades are connected to the end of the folding blade clamp assembly 3; and the blades are arranged parallel to the folding blade clamp assembly 3; when the folding blade clamp assembly 3 is parallel to the direction of the pitch hub 2, the folding blade clamp assembly 3 is in an unfolded state, and the blades are in an unfolded state; when the folding blade clamp assembly 3 is perpendicular to the direction of the pitch hub 2, the folding blade clamp assembly 3 is in a folded state, and the blades are in a folded state; the torsion spring 4 is sleeved on the swinging bolt 6, and the upper torsion arm 41 of the torsion spring 4 extends into the through hole 21 of the pitch hub 2 The lower torsion arm 42 of the torsion spring 4 abuts against the bottom of the folding blade clamp assembly 3; the centrifugal swing limiter 5 is movably connected to the variable pitch propeller hub 2 through a rotating shaft, and when the folding blade clamp assembly 3 is unfolded, it is clamped at the tail of the folding blade clamp assembly 3. The centrifugal swing limiter 5 is symmetrically connected to both sides of the variable pitch propeller hub 2, that is, the centrifugal swing limiter 5 is symmetrically connected to the front side and the rear side of the variable pitch propeller hub 2.

[0034] like Figure 1As shown, the hub center piece 1 has a center hole in the middle, and the rotating shaft of the unmanned helicopter penetrates into the center hole. The hub center piece 1 is fixedly connected to the rotating shaft. When the rotating shaft rotates, the hub center piece 1 rotates with the rotating shaft. The hub center piece 1 is used to drive the variable pitch hub 2, the folding blade clamp assembly 3 and the blade to rotate. The variable pitch hub 2 is used to connect the folding blade clamp assembly 3 and the hub center piece 1 together. The torsion spring 4 and the centrifugal pendulum limiter 5 are both used to limit the position of the folding blade clamp assembly 3, and limit the angle that the folding blade clamp assembly 3 can deviate upward or downward when it is in the unfolded state.

[0035] like Figure 1 As shown, one end of the folding blade clamp assembly 3 has a limiting mechanism 31, which is used to cooperate with the centrifugal limiter 5 to limit the angle at which the folding blade clamp assembly 3 can be deflected upward or downward after being unfolded, and the other end has a connecting portion 32 for connecting the blades. When the folding blade clamp assembly 3 is in the unfolded state; the centrifugal swing limiter 5 is clamped in the limiting mechanism 31, and the angle at which the folding blade clamp assembly 3 can be deflected upward and downward relative to the variable pitch hub 2 is limited. Since the rotor of the unmanned helicopter includes an upper rotor and a lower rotor, and the upper rotor and the lower rotor are arranged at a certain distance, if the angle at which the blade deflects upward or downward is too large, the upper blade and the lower blade will beat. Therefore, limiting the angle at which the folding blade clamp assembly 3 can be deflected upward or downward can limit the angle at which the upper blade and the lower blade can be deflected upward or downward, thereby preventing the beating phenomenon; when the folding blade clamp assembly 3 is in the folded state, the centrifugal swing limiter 5 is separated from the limiting mechanism 31.

[0036] like Figure 1 As shown, the connecting portion 32 of the folding paddle clamp assembly 3 is provided with a paddle installation slot 33, and the paddle installation slot 33 is used for installing the paddle.

[0037] like Figure 2 As shown, the torsion spring 4 is sleeved on the swing bolt 6. When the folding oar clamp assembly 3 is in the unfolded state, the upper torsion arm 41 and the lower torsion arm 42 are parallel and inclined. The upper torsion arm 41 extends obliquely upward along the swing bolt 6 and is restricted in the through hole 21. The function of the through hole 21 is to limit the position of the upper torsion arm 41, which cannot move left or right and can only move obliquely upward or downward in the hole; the lower torsion arm 42 extends obliquely downward along the swing bolt 6 and abuts against the bottom of the folding oar clamp assembly 3, providing a certain supporting force for the folding oar clamp assembly 3.

[0038] The torsion spring 4 is arranged on the variable pitch hub 2, and no additional structure is required. The torsion spring 4 is used to provide power for the initial deployment of the blades. Under the action of inertial force, the blades can be deployed to more than 70 degrees, which is convenient for the smooth deployment of the rotor. For a rotor with a larger diameter, it is not easy to deploy the blades mainly by the action of centrifugal force. The torsion spring 4 of the present invention provides power for the initial deployment of the blades, which is not only suitable for the deployment of small diameter blades, but also suitable for the deployment of large diameter blades.

[0039] like Figure 3 As shown, the folding paddle clamp assembly 3 is in the folded state, and the upper torsion arm 41 is retracted along the through hole 21 for a certain length relative to the folding paddle clamp assembly 3 being in the unfolded state. The lower torsion arm 42 extends obliquely downward along the swing bolt 6 and abuts against the bottom of the folding paddle clamp assembly 3, providing a certain supporting force to the folding paddle clamp assembly 3.

[0040] like Figure 4 As shown, the variable pitch hub 2 has an open slot 22, the swing bolt 6 passes through the side wall of the open slot 22, the torsion spring 4 is sleeved on the swing bolt 6 and is located inside the open slot 22, the through hole 21 is opened on the top wall of the open slot 22, the lower wall of the open slot 22 is opened with a through slot, the upper torsion arm 41 of the torsion spring 4 extends into the through hole 21, and the lower torsion arm 42 extends through the through slot to the bottom of the folding blade clamp assembly 3. The folding blade clamp assembly 3 has a connecting side plate 34, the connecting side plates 34 are symmetrically arranged on both sides of the folding blade clamp assembly 3, the connecting side plates 34 are opened with holes that can penetrate the swing bolt 6, the connecting side plates 34 are sleeved on the swing bolt 6, the swing bearing 7 is sleeved on the swing bolt 6 and fixed in the hole of the connecting side plate 34, and the end of the variable pitch hub 2 extends between the connecting side plates 34 on both sides of the folding blade clamp assembly 3.

[0041] like Figure 5 As shown, the limiting mechanism 31 includes an upper limit projection 311 and a lower limit projection 312 which are spaced apart, and a limiting groove 313 is formed between the upper limit projection 311 and the lower limit projection 312; the centrifugal swing limiter 5 includes a reverse stop claw 51. The reverse stop claw 51 is limited in the limiting groove 313 to limit the downward deflection angle of the folding paddle clamp assembly 3.

[0042] When the rotor is in the folded state, the centrifugal swing limiter 5 and the folding blade clamp assembly 3 are in the state as shown in FIG. Figure 5 In the position shown in , the centrifugal pendulum limiter 5 is separated from the folding paddle clamp assembly 3, and the centrifugal pendulum limiter 5 does not have a limiting effect on the folding paddle clamp assembly 3.

[0043] like Figure 6 As shown, when the rotor is in the unfolded state, the folding blade clamp assembly 3 is in a horizontal state. When the folding blade clamp assembly 3 is in the unfolded state, the backstop claw 51 is clamped in the limit groove 313, the upper limit projection 311 is located above the centrifugal pendulum limiter 5, and the lower limit projection 312 is respectively located at the bottom of the backstop claw 51. The upper limit projection 311 is limited above the centrifugal pendulum limiter 5 to limit the upward deflection angle of the folding blade clamp assembly 3; the lower limit projection 312 is limited below the backstop claw 51 to limit the downward deflection angle of the folding blade clamp assembly 3.

[0044] like Figure 6As shown, one side of the lower limit projection 312 close to the limit groove 313 is a plane, and the other side is an arc transition surface; when the reverse stop claw 51 is engaged in the limit groove 313, the side of the reverse stop claw 51 in contact with the lower limit projection 312 is a plane. The opposite surfaces of the reverse stop claw 51 and the lower limit projection 312 are both planes, and they are not easy to slip off after being engaged, and the limiting effect is good. When the folding paddle clamp assembly 3 is transferred from the folded state to the unfolded state, the surface of the lower limit projection 312 close to the centrifugal pendulum stopper 5 is an arc transition surface, which can ensure the smooth unfolding of the folding paddle clamp assembly 3 and prevent the lower limit projection 312 from colliding with the centrifugal pendulum stopper 5.

[0045] like Figure 6 As shown, one end of the centrifugal pendulum stopper 5 close to the upper limit projection 311 is a circular arc portion 53, and the other end is a protruding rod 52. The protruding rod 52 is conducive to the centrifugal pendulum stopper 5 swinging under the action of centrifugal force.

[0046] When the rotor starts to rotate, the centrifugal swing limiter 5 tends to swing rightward due to the centrifugal force, the folding blade clamp assembly 3 gradually unfolds, and the reverse stop claw 51 of the centrifugal swing limiter 5 extends into the limiting groove 313 of the folding blade clamp assembly 3.

[0047] like Figure 7 As shown, if a special situation occurs and the blade swings downward, the reverse stop claw 51 is stuck on the top of the lower limit block 312, and the extension rod 52 is stuck on the bottom of the lower limit block 312, and the downward swing angle of the blade is limited. According to one embodiment of the present invention, the downward swing angle of the blade is limited to 5 degrees.

[0048] like Figure 8 As shown, if a special situation occurs and the blade swings upward, the upper limit stop 311 collides with the centrifugal swing limiter 5, and the centrifugal swing limiter 5 limits the upper limit stop 311. The upper limit stop 311 hits the arc portion 53 of the centrifugal swing limiter 5, and the folding blade clamp assembly 3 can no longer deflect upward, and the blade can no longer swing upward. According to one embodiment of the present invention, the upward deflection angle of the blade is limited to 8 degrees.

[0049] like Figure 6 As shown, when the folding paddle clamp assembly 3 is in the unfolded state, the lower limit projection 312 is clamped in the groove between the extending rod 52 and the reverse stop claw 51 .

[0050] According to a specific embodiment of the present invention, the variable pitch hub 2 is rotatably connected to the hub central component 1, and the variable pitch hub 2 drives the folding blade clamp assembly 3 and the blade to deflect at a certain angle.

[0051] According to a specific embodiment of the present invention, the rotor also includes a pitch rocker arm 8, which is connected to the pitch hub 2 through a pitch hub assembly 9. The pitch hub assembly 9 is used to connect the pitch rocker arm 8 and the pitch hub 2. The pitch rocker arm 8 is used to drive the pitch hub assembly 9 and the pitch hub 2 to rotate relative to the hub central piece 1.

[0052] According to a specific embodiment of the present invention, the swing bolt 6 is fixedly connected to one end of the variable pitch hub 2 away from the hub central part 1, and the two ends of the folding blade clamp assembly 3 are respectively mounted on the two ends of the swing bolt 6 and are rotatably connected to the swing bolt 6 through a swing bearing 7.

[0053] The beneficial effects achieved by this application are as follows:

[0054] (1) The present application adopts a torsion spring and a centrifugal pendulum limiter as dual insurances to limit the limiting angle of the folding propeller clamp assembly, that is, the angle at which the folding propeller clamp assembly can be displaced upward or downward relative to the variable pitch propeller hub. When the speed of the motor connected to the central part of the propeller hub is uneven or the helicopter encounters strong winds during flight, the present application can prevent the upper and lower blades from being displaced upward or downward by too large an angle, causing the phenomenon of flapping propellers, thereby improving the stability and safety of the unmanned helicopter's flight.

[0055] (2) The limiting angle of the present application can be changed according to actual conditions, effectively preventing the upper and lower blades of the rotor from hitting each other during deployment and flight, thereby improving the flight stability of the unmanned helicopter.

[0056] (3) The torsion spring of the present application provides power for the initial deployment of the blades, which is not only beneficial to the deployment of small-diameter rotors, but also beneficial to the deployment of large-diameter rotors.

[0057] (4) This application does not require excessive weight increase while meeting the requirements and functions of the basic design, and is easy to maintain and process.

[0058] The above is a detailed description of an embodiment of the present invention, but the content is only a preferred embodiment of the present invention and cannot be considered to limit the scope of implementation of the present invention. All equivalent changes and improvements made within the scope of the present invention should fall within the scope of the patent coverage of the present invention.

Claims

1. A coaxial unmanned helicopter folding rotor, characterized in that: include: Variable pitch propeller hub, folding propeller clamp assembly, propeller blades, torsion springs and centrifugal pendulum limiter, The folding blade clamp assembly is rotatably connected to the end of the variable pitch blade hub via a flapping bolt and a flapping bearing; The paddle is connected to the end of the folding paddle clamp assembly; The torsion spring is sleeved on the swinging bolt, the upper torsion arm of the torsion spring extends into the through hole of the variable pitch propeller hub, and the lower torsion arm of the torsion spring abuts against the bottom of the folding propeller clamp assembly; The centrifugal pendulum limiter is movably connected to the variable pitch propeller hub via a rotating shaft, and is clamped at the tail of the folding propeller clamp assembly when the folding propeller clamp assembly is unfolded; The centrifugal pendulum limiter is symmetrically connected to both sides of the variable pitch propeller hub; The folding paddle clamp assembly has a limiting mechanism at one end and a connecting portion for connecting a paddle blade at the other end. When the folding paddle clamp assembly is in an unfolded state, the centrifugal pendulum limiter is clamped in the limiting mechanism. When the folding paddle clamp assembly is in a folded state, the centrifugal pendulum limiter is separated from the limiting mechanism. The limiting mechanism comprises an upper limit moving protrusion and a lower limit moving protrusion which are arranged at intervals, and a limiting groove is formed between the upper limit moving protrusion and the lower limit moving protrusion; the centrifugal pendulum limiter comprises a reverse stop claw, and when the folding paddle clamp assembly is in an unfolded state, the reverse stop claw is clamped in the limiting groove, the upper limit moving protrusion is located above the centrifugal pendulum limiter, and the lower limit moving protrusions are respectively located at the bottom of the reverse stop claw; The side of the lower limit block close to the limit groove is a plane, and the other side is an arc transition surface; when the reverse stop claw is clamped in the limit groove, the side of the reverse stop claw in contact with the lower limit block is a plane; One end of the centrifugal pendulum limiter close to the upper limit projection is an arc portion, and the other end is a protruding rod; When the folding paddle clamp assembly is in an unfolded state, the lower limit projection is clamped in a groove between the extension rod and the reverse stop claw; The swing bolt is fixedly connected to one end of the variable pitch hub away from the hub, and the two ends of the folding blade clamp assembly are respectively sleeved on the two ends of the swing bolt and are rotatably connected to the swing bolt through a swing bearing.

2. The coaxial unmanned helicopter folding rotor according to claim 1, characterized in that: The variable pitch propeller hub is rotatably connected to the propeller hub central piece.

3. The coaxial unmanned helicopter folding rotor according to claim 2, characterized in that: It also includes a variable pitch rocker arm, which is connected to the variable pitch propeller hub.

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