Variable pitch axle quadcopter

Abstract

The application discloses a variable-pitch axle-distance four-rotor aircraft and belongs to the technical field of aircraft design. The end of each first frame arm is horizontally rotatable with an outer arm. The variable-pitch vane and the center of the main frame body are coaxially rotatably connected. The length of the second frame arm is greater than that of the first frame arm, and the end of the second frame arm is open to a track groove in the vertical direction. The outer arm is provided with a variable-pitch limiting piece perpendicular to the outer arm. One end of the variable-pitch limiting piece penetrates through the track groove and is in sliding fit with the track groove. The top side of the outer arm away from the first frame arm is provided with a lifting assembly. The main frame body is provided with an angle adjusting assembly. The angle adjusting assembly is used for driving the horizontal rotation of the variable-pitch vane, thereby driving the synchronous horizontal rotation of the four outer arms, adjusting the distance between the lifting assembly and the center of the main frame body, and guaranteeing the safety performance of the aircraft in different axle-distance states, so that the aircraft can land and deliver goods in a narrow area.

Description

Technical Field

[0001] The present invention relates to the technical field of aircraft design, and in particular to a variable-paddle wheelbase quadrotor aircraft. Background Art

[0002] Multi-rotor unmanned aerial vehicles (UAVs) are a recent emerging technology, providing powerful tools for aerial photography, surveying and mapping, and express delivery, finding widespread use in numerous fields. With the increasing popularity and application of multi-rotor aircraft, the need to carry larger equipment or heavier objects has emerged. Consequently, multi-rotor aircraft with large payloads typically have a longer wheelbase and are difficult to carry. Quadcopters utilize two pairs of rotors rotating in opposite directions to eliminate torque on the aircraft while simultaneously generating lift, side force, and the required torque.

[0003] Through extensive experiments, it was found that large-wheelbase multi-rotor aircraft have high wind resistance and high stability, but due to high drag, they have slow flight speeds and are suitable for tasks such as high-altitude aerial photography and mapping. Small-wheelbase aircraft have fast flight speeds and flexibility, but poor wind resistance and stability, making them suitable for tasks such as low-altitude aerial photography and stunts. However, from a development perspective, quadcopters still have some shortcomings. They are inherently motion-coupled systems, with their direction and attitude coupled during flight. When designed as small aircraft with a fixed wheelbase, their load capacity is limited, and the aircraft's lift and weight are relatively low, resulting in poor flexibility, stability, and versatility.

[0004] In actual applications, if goods need to be delivered to customers' homes, the wheelbase of the aircraft needs to be changed according to the requirements of different altitudes. If the pitch or wheelbase is simply reduced, the safety performance of the aircraft during flight cannot be guaranteed, making it impossible to land in a narrow area to deliver goods. Summary of the Invention

[0005] In response to the problems existing in the above-mentioned fields, the present invention designs a variable-pitch wheelbase quadrotor aircraft, which can solve the technical problem that if the pitch or wheelbase is simply reduced, the safety performance of the aircraft during flight cannot be guaranteed, making it impossible to land in a narrow area to deliver goods.

[0006] In order to solve the above technical problems, the present invention proposes a variable-pitch quadrotor aircraft, comprising a main frame and variable-pitch blades;

[0007] The main frame has four first arms, which are evenly arranged along the circumference; each end of the first arms is horizontally rotated to form an outer arm;

[0008] The variable-pitch piece has four second frame arms, which are evenly arranged in the circumferential direction; the variable-pitch piece is located above the main frame body and is coaxially connected with the center of the main frame body; the length of the second frame arm is greater than that of the first frame arm; the end of the second frame arm is provided with a track groove in the vertical direction; a variable-pitch limiting piece perpendicular to the outer arm is arranged on the outer arm; one end of the variable-pitch limiting piece passes through the track groove and is in sliding fit with the track groove; a lifting assembly is arranged on the outer arm away from the top side of the first frame arm.

[0009] An angle adjusting assembly is arranged on the main frame body; the angle adjusting assembly is used to drive the horizontal rotation of the variable-pitch piece, thereby driving the synchronous horizontal rotation of the four outer arms, and adjusting the distance between the lifting assembly and the center of the main frame body.

[0010] Preferably, a plurality of first limiting holes are arranged on the top of the outer arm in the vertical direction, and the variable-pitch limiting piece is connected with any one of the first limiting holes.

[0011] Preferably, a convex groove is fixedly arranged on one end of the outer arm close to the variable-pitch limiting piece in the horizontal direction, the end of the first frame arm is provided with a horizontal limiting groove, the convex groove and the horizontal limiting groove are matched and are inserted in the horizontal direction, a second limiting hole is arranged in the vertical direction through the horizontal limiting groove, a vertical limiting piece passes through the second limiting hole, and the end of the first frame arm is hinged with the horizontal limiting groove through the vertical limiting piece.

[0012] Preferably, the angle adjusting assembly comprises a motor, a worm, and a sector-shaped worm gear arranged between two second frame arms adjacent to the variable-pitch piece; the motor is arranged on the main frame body, the output shaft of the motor is in transmission connection with the worm, and the worm is in mesh with the sector-shaped worm gear.

[0013] Preferably, a fairing is further arranged on the top of the main frame body and the variable-pitch piece, the outer wall of the fairing is provided with a plurality of avoiding grooves in the horizontal direction and a plurality of limiting grooves in the vertical direction; the top of the limiting groove is in communication with the bottom of the avoiding groove; the limiting groove is in clamping connection with the first frame arm, and the avoiding groove is in sliding fit with the second frame arm.

[0014] Preferably, the variable-pitch limiting piece is a shaft pin, the shaft pin passes through the track groove and is connected with the first limiting hole.

[0015] Preferably, the opening angle of the horizontal limiting groove is 180 degrees.

[0016] Preferably, the sector-shaped worm gears installed on one side of two adjacent second frame arms are 90 degrees.

[0017] Preferably, the lifting component comprises a paddle and a paddle shaft, the paddle shaft is fixedly connected with the top of the outer arm, and the paddle shaft is bolted with the paddle.

[0018] Preferably, four landing gears are further included; each of the landing gears is fixedly connected with the bottom of each of the first frame arms and is perpendicular to the first frame arms; the landing gears, the first frame arms and the fairing are all hollow structures.

[0019] Compared with the prior art, the present application has the following beneficial effects:

[0020] The horizontal limiting groove is arranged, the end of the first frame arm and one end of the outer arm are rotationally connected through the vertical limiting member, the variable-distance limiting member is arranged to slide the outer arm with the second frame arm, the length of the second frame arm is greater than that of the first frame arm, so that the first frame arm, the second frame arm and the outer arm form a deformable triangle along the horizontal direction; the angle adjusting component is arranged, the variable-distance piece is driven to rotate, the variable-distance limiting member slides in the track groove, so as to drive the outer arm to rotate horizontally, change the length of the second frame arm in the triangle, further drive the rotation of the outer arm, change the included angle between the outer arm and the first frame arm, and finally change the wheelbase of the aircraft.

[0021] When the outer arm is rotated to the parallel position with the main frame body, the shaft pin on the outer arm slides to the outermost limit of the sliding groove arranged on the variable-distance piece, at this time, the whole machine is locked, and is in the maximum pitch state, the counterclockwise locking ability is provided by the worm and gear mechanism, the structure will not be opened due to external force, and in the flight state, even if strong wind is encountered, stable flight can still be achieved. When the shaft pin on the outer arm slides to the inner limit position of the track groove of the variable-distance piece, the distance is collected, at this time, the outer arm is completely retracted, and the pitch is at the minimum, which is helpful for the aircraft to quickly complete landing. When the aircraft flies to a position 5 meters away from the customer's balcony and hovers, the distance is collected, and the aircraft directly flies to a position 1 meter away from the ground on the user's balcony and then descends to complete the landing operation, so that the delivery task is completed. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 is the overall structural design drawing of the present application;

[0023] Figure 2 is the internal structure drawing of the aircraft without a fairing of the present application;

[0024] Figure 3 is the main frame body structure drawing of the present application;

[0025] Figure 4 is the main frame body structure sectional view of the present application;

[0026] Figure 5 is the hollow structure drawing of the outer arm of the present application;

[0027] Figure 6 It is a structural diagram of the pitch-variable piece of the present invention;

[0028] Figure 7 It is a structural diagram of the fairing of the present invention;

[0029] FIG8 is a schematic diagram of the structural deformation of the aircraft of the present invention at different viewing angles, wherein:

[0030] FIG8( a ) is a schematic structural diagram of the aircraft of the present invention at a viewing angle of 0 degrees;

[0031] FIG8( b ) is a schematic structural diagram of the aircraft of the present invention at a 30-degree viewing angle;

[0032] FIG8( c ) is a schematic structural diagram of the aircraft of the present invention at a 60-degree viewing angle;

[0033] FIG8( d ) is a schematic structural diagram of the aircraft of the present invention at a 90-degree viewing angle.

[0034] Among them: 1. Outer arm; 2. Fairing; 3. Pitch blade; 4. Main frame; 5. Blade; 6. Bolt. DETAILED DESCRIPTION

[0035] The following is a combination of the embodiments of the present invention Figure 1 -8, clearly and completely describe the technical solutions in the embodiments of the present invention.

[0036] It should be understood that the terms used in the present invention are only used to describe particular embodiments and are not intended to limit the present invention.

[0037] Example

[0038] like Figures 1-4 As shown, a variable-pitch quadrotor aircraft includes a main frame 4 and a pitch plate 3. The main frame 4 has four first arms, which are evenly spaced along the circumference. Each first arm has an outer arm 1 at its end for horizontal rotation, allowing only horizontal rotation of the outer arm 1 at the end of the first arm. The pitch plate 3 has four second arms, which are evenly spaced along the circumference. This uniform arrangement enhances the stability of the aircraft. The pitch plate 3 is located above the main frame 4 and is coaxially rotatably connected to the center of the main frame 4. The second arm is longer than the first arm, and a track groove is defined at the end of the second arm in the vertical direction. The outer arm 1 is provided with a pitch limiter perpendicular to the outer arm 1. One end of the pitch limiter passes through the track groove and is slidably connected to the track groove. A lift assembly is mounted on the side of the outer arm 1 away from the top of the first arm, so that the first arm, the second arm, and the outer arm form a horizontally deformable triangle.

[0039] The angle adjusting assembly is arranged on the main frame body 4 and is used for driving the variable-pitch piece 3 to rotate horizontally, thereby driving the four outer arms 1 to rotate horizontally synchronously, adjusting the distance between the lifting assembly and the center of the main frame body 4, i.e. the distance between the center of the propeller shaft and the center of the main frame body 4, which is referred to as the wheelbase.

[0040] Working principle: The angle adjusting assembly drives the variable-pitch piece 3 to rotate horizontally, so that the variable-pitch limiting piece slides in the track groove, thereby driving the outer arm 1 to rotate horizontally, changing the length of the second frame arm in the horizontally deformable triangle composed of the first frame arm, the second frame arm and the outer arm 1, further driving the rotation of the outer arm 1, so that the included angle between the outer arm 1 and the first frame arm changes, and finally the wheelbase of the aircraft is changed.

[0041] As shown in FIG. 8, it is a structural deformation schematic diagram of the aircraft at different angle views, wherein FIG. 8(a) is a variable-pitch structure schematic diagram of the aircraft at a 0-degree view, at this time the wheelbase is maximum; FIG. 8(b) is a structural schematic diagram of the aircraft at a 30-degree view; FIG. 8(c) is a structural schematic diagram of the aircraft at a 60-degree view, at this time the wheelbase of the aircraft is smaller than the wheelbase at the 30-degree view; FIG. 8(d) is a structural schematic diagram of the aircraft at a 90-degree view, at this time the included angle between the outer arm 1 and the end of the second frame arm of the variable-pitch piece 3 is perpendicular, which is also the limit position of the horizontal rotation of the outer arm, as can be seen from FIG. 8(d), the sliding position of the shaft pin on the outer arm is at the inner limit of the track groove, at this time the wheelbase is minimum.

[0042] As shown in FIG. 8, it is a structural deformation schematic diagram of the aircraft at different angle views, wherein FIG. 8(a) is a variable-pitch structure schematic diagram of the aircraft at a 0-degree view, at this time the wheelbase is maximum; FIG. 8(b) is a structural schematic diagram of the aircraft at a 30-degree view; FIG. 8(c) is a structural schematic diagram of the aircraft at a 60-degree view, at this time the wheelbase of the aircraft is smaller than the wheelbase at the 30-degree view; FIG. 8(d) is a structural schematic diagram of the aircraft at a 90-degree view, at this time the included angle between the outer arm 1 and the end of the second frame arm of the variable-pitch piece 3 is perpendicular, which is also the limit position of the horizontal rotation of the outer arm, as can be seen from FIG. 8(d), the sliding position of the shaft pin on the outer arm is at the inner limit of the track groove, at this time the wheelbase is minimum. Figure 5 As shown in FIG. 8, it is a structural deformation schematic diagram of the aircraft at different angle views, wherein FIG. 8(a) is a variable-pitch structure schematic diagram of the aircraft at a 0-degree view, at this time the wheelbase is maximum; FIG. 8(b) is a structural schematic diagram of the aircraft at a 30-degree view; FIG. 8(c) is a structural schematic diagram of the aircraft at a 60-degree view, at this time the wheelbase of the aircraft is smaller than the wheelbase at the 30-degree view; FIG. 8(d) is a structural schematic diagram of the aircraft at a 90-degree view, at this time the included angle between the outer arm 1 and the end of the second frame arm of the variable-pitch piece 3 is perpendicular, which is also the limit position of the horizontal rotation of the outer arm, as can be seen from FIG. 8(d), the sliding position of the shaft pin on the outer arm is at the inner limit of the track groove, at this time the wheelbase is minimum.

[0043] As shown in FIG. 8, it is a structural deformation schematic diagram of the aircraft at different angle views, wherein FIG. 8(a) is a variable-pitch structure schematic diagram of the aircraft at a 0-degree view, at this time the wheelbase is maximum; FIG. 8(b) is a structural schematic diagram of the aircraft at a 30-degree view; FIG. 8(c) is a structural schematic diagram of the aircraft at a 60-degree view, at this time the wheelbase of the aircraft is smaller than the wheelbase at the 30-degree view; FIG. 8(d) is a structural schematic diagram of the aircraft at a 90-degree view, at this time the included angle between the outer arm 1 and the end of the second frame arm of the variable-pitch piece 3 is perpendicular, which is also the limit position of the horizontal rotation of the outer arm, as can be seen from FIG. 8(d), the sliding position of the shaft pin on the outer arm is at the inner limit of the track groove, at this time the wheelbase is minimum.

[0044] As shown in FIG. 8, it is a structural deformation schematic diagram of the aircraft at different angle views, wherein FIG. 8(a) is a variable-pitch structure schematic diagram of the aircraft at a 0-degree view, at this time the wheelbase is maximum; FIG. 8(b) is a structural schematic diagram of the aircraft at a 30-degree view; FIG. 8(c) is a structural schematic diagram of the aircraft at a 60-degree view, at this time the wheelbase of the aircraft is smaller than the wheelbase at the 30-degree view; FIG. 8(d) is a structural schematic diagram of the aircraft at a 90-degree view, at this time the included angle between the outer arm 1 and the end of the second frame arm of the variable-pitch piece 3 is perpendicular, which is also the limit position of the horizontal rotation of the outer arm, as can be seen from FIG. 8(d), the sliding position of the shaft pin on the outer arm is at the inner limit of the track groove, at this time the wheelbase is minimum. Figure 2 Figure 6 ​As shown, the angle adjustment assembly includes a motor and a worm, and a sector worm gear arranged between the two adjacent second arms of the variable pitch plate 3; the motor is arranged on the main frame body 4, and the output shaft of the motor is in transmission connection with the worm; the worm is in engagement with the sector worm gear. The worm drives the sector worm gear to rotate, drives the second arm to rotate horizontally, and makes the variable pitch limiting piece slide in the track groove, further changing the wheelbase. The sector worm gear installed on one side of the two adjacent second arms is 90 degrees, which can reinforce the stability of the second arm of the variable pitch plate 3 during rotation.

[0045] As shown in Figure 7 , the fairing 2 arranged is ellipsoidal, the wall thickness is 0.8mm, and grooves are arranged in four directions of the fairing for placing and movement of the main frame body 4 and the variable pitch plate 3. The fairing 2 is arranged on the top of the main frame body 4 and the variable pitch plate 3, the outer wall of the fairing 2 is provided with a plurality of avoiding grooves in the horizontal direction and a plurality of limiting grooves in the vertical direction; the top of the limiting groove is in communication with the bottom of the avoiding groove; the limiting groove is in clamping connection with the first arm, and the avoiding groove is in sliding connection with the second arm.

[0046] The avoiding groove is arranged to make the second arm of the variable pitch plate 3 rotate in a certain range in the horizontal direction, so as to avoid damage to the deformable triangular structure composed of the first arm, the second arm and the outer arm due to too large rotation angle of the variable pitch plate 3. The limiting groove is arranged in clamping connection with the first arm, so as to increase the connection stability between the fairing 2 and the main frame body.

[0047] As shown in Figure 5 , the variable pitch limiting piece is arranged as a shaft pin, which is connected with the first limiting hole through the track groove. The top structure of the shaft pin can limit the track groove to prevent the track groove from being separated during sliding.

[0048] As shown in Figure 3 , the opening angle of the horizontal limiting groove is 180 degrees, which prevents the outer arm from rotating too much in the horizontal direction, so as to prevent the lift from being too small and the flight performance from being reduced. At the same time, it may cause the lift devices of the aircraft to collide with each other and cause unsafe accidents.

[0049] As shown in Figure 1 and Figure 2 , the lift assembly includes a paddle 5 and a paddle shaft, the paddle shaft is fixedly connected with the top of the outer arm 1, and the paddle shaft is connected with the paddle 5 through a bolt 6. The paddle 5 rotates to generate lift, which provides power for the flight of the aircraft.

[0050] Further comprising landing gears, each landing gear is fixedly connected with the bottom of each first arm and perpendicular to the first arm; the main frame body 4, the landing gear, the first arm and the fairing 2 are all hollow structures, as shown in Figures 4-5 , and a plurality of air holes are horizontally arranged in the length direction of the outer arm 1, so as to reduce the load of the aircraft.

[0051] For example, Figure 5 As shown, in order to reduce the mass and increase the elasticity of the outer arm, 10 circular holes with a diameter of 1 cm are punched from left to right along the Y-axis direction, 4 similar circular holes are punched along the Z-axis direction, and 1 circular hole is punched along the X-axis direction. The above circular holes are penetrated until they end in front of the left hole. This can also reduce the overall load of the aircraft and increase the continuous endurance of the aircraft.

[0052] In particular, during takeoff, the aircraft must maintain a minimum propeller wheelbase to avoid excessive impact on ground hazards. When the aircraft reaches a safe altitude of 25 meters, it hovers and activates the angle adjustment assembly, driving the pitch-changing worm to drive the fan-shaped worm gear on the pitch-changing piece 3, causing the pitch-changing piece 3 to rotate counterclockwise relative to the main frame 4. At the same time, the pitch-changing piece 3 drives the axle pin on the outer arm 1, causing the outer arm 1 to rotate. When the outer arm 1 rotates to a position parallel to the main frame 4, the axle pin on the outer arm 1 slides to the outermost limit of the slide groove provided on the pitch-changing piece 3. At this point, the entire aircraft is locked and in the maximum propeller pitch state. Afterwards, the aircraft performs level flight operations.

[0053] During level flight, the aircraft's maximum propeller pitch ensures excellent stability and maneuverability. At maximum pitch, the aircraft's variable pitch mechanism is locked clockwise, while the worm gear mechanism provides counterclockwise locking. This structure is immune to external forces, ensuring stable flight even in strong winds.

[0054] If the maximum power of a single rotorcraft engine remains unchanged, increasing the wheelbase can increase the maximum level flight speed of the aircraft. This is verified as follows: Assume that a quadrotor with a propeller wheelbase of r and a quadrotor with a propeller wheelbase of R generate the same maximum lift F as the single motor and rotor. When both aircraft's motors are operating at maximum power, to achieve level flight, the power of the motor in the direction of flight must be reduced. The aircraft with the smaller propeller wheelbase (r) needs to reduce the power of both motors in the direction of flight more to achieve the same "head-down" angle as the aircraft with the wheelbase of R. Therefore, if the output power of the lift motors of the quadrotor aircraft is the same, the aircraft with the propeller wheelbase of R will have a higher level flight speed.

[0055] During the landing phase, when the aircraft reaches 25 meters above the destination and hovers, the "pitch retraction" operation begins. The motor rotates in the opposite direction, driving the pitch plate 3 counterclockwise. The axle pin on the outer arm 1 gradually slides inward from the outer limit of the pitch plate 3, and the outer arm 1 retracts inward. When the axle pin on the outer arm 1 slides to the inner limit of the track groove of the pitch plate 3, it stops sliding. At this time, the outer arm 1 is fully retracted and the pitch is at its minimum. The aircraft then descends and lands, completing the landing operation.

[0056] The design of the present application is to complete the logistics end distribution task, and simulate the opening balcony which intends to send goods directly to the customer's home. When the aircraft flies to 5 meters away from the customer's balcony, it hovers and starts to collect the propeller. After the propeller collection operation is completed, it flies directly to the user's balcony 1 meter away from the ground, then descends, completes the landing operation, and thus completes the distribution task.

[0057] Anti-fatigue verification, the main fatigue point of the aircraft is the connection between the main frame body 4 and the outer arm 1, followed by the sliding friction between the trajectory groove of the variable pitch piece 3 and the shaft pin connected on the outer arm 1, and finally the friction between the worm gear and the sector worm gear installed on one side of the adjacent two second frame arms. The present application uses Teflon layer at the three places, thereby increasing the flight performance and service life of the aircraft.

[0058] The above is only the preferred embodiment of the present application, but the protection scope of the present application is not limited to this. Any skilled person in the art can make equivalent replacement or change according to the technical solution and the inventive concept of the present application within the technical range disclosed by the present application, which should be covered within the protection scope of the present application.

[0059] In addition, all technical and scientific terms used herein have the same meaning as generally understood by those skilled in the art of the present application. All documents mentioned in the specification are incorporated by reference to disclose and describe the methods related to the documents. In the event of conflict with any incorporated document, the content of the specification shall prevail.

[0060] Many modifications and variations of the specific embodiments of the present application can be made without departing from the scope or spirit of the present application, which will be apparent to those skilled in the art. Other embodiments obtained from the specification of the present application will be apparent to those skilled in the art. The specification and examples of the present application are only exemplary.

Claims

1. A quadrotor aircraft with variable-pitch propellers, characterized in that: It comprises a main frame (4) and a pitch-changing piece (3); The main frame (4) has four first frame arms, which are evenly arranged along the circumference; an outer arm (1) is horizontally rotated at the end of each first frame arm; The pitch-changing piece (3) has four second arms, and the four second arms are evenly arranged along the circumference; the pitch-changing piece (3) is located above the main frame (4) and is coaxially connected to the center of the main frame (4); the length of the second arm is greater than the length of the first arm; a track groove is opened at the end of the second arm in the vertical direction; a pitch-changing limiter is provided on the outer arm (1) and is perpendicular to the outer arm (1); one end of the pitch-changing limiter passes through the track groove and is slidably matched with the track groove; a lift assembly is installed on the top side of the outer arm (1) away from the first arm; An angle adjustment component is mounted on the main frame (4); the angle adjustment component is used to drive the pitch-variable piece (3) to rotate horizontally, thereby driving the four outer arms (1) to rotate horizontally synchronously, thereby adjusting the distance between the lift component and the center of the main frame (4); The top of the outer arm (1) is provided with a plurality of first limiting holes in a vertical direction, and the variable distance limiting member is connected to any one of the first limiting holes; The outer arm (1) is fixedly provided with a convex groove in the horizontal direction at one end close to the variable distance limiting member, and the end of the first frame arm is provided with a horizontal limiting groove, the convex groove cooperates with the horizontal limiting groove and is plugged in the horizontal direction; a second limiting hole is opened in the vertical direction through the horizontal limiting groove; a vertical limiting member passes through the second limiting hole, and the end of the first frame arm is hinged to the horizontal limiting groove through the vertical limiting member.

2. The variable-pitch quadrotor aircraft according to claim 1, characterized in that: The angle adjustment assembly comprises a motor and a worm, and a sector-shaped worm gear arranged between two adjacent second frame arms of the pitch-changing piece (3); the motor is mounted on the main frame (4), and its output shaft is transmission-connected to the worm; the worm is meshed with the sector-shaped worm gear.

3. The variable-pitch quadrotor aircraft according to claim 1, characterized in that: The invention also includes a fairing (2), which is mounted on the top of the main frame (4) and the pitch-variable plate (3), and the outer wall of the fairing (2) is provided with a plurality of avoidance grooves in the horizontal direction and a plurality of limiting grooves in the vertical direction; the top of the limiting groove is connected to the bottom of the avoiding groove; the limiting groove is engaged with the first frame arm, and the avoiding groove is slidably matched with the second frame arm.

4. The variable-pitch quadrotor aircraft according to claim 1, characterized in that: The variable distance limiting member is an axle pin, which passes through the track groove and is connected to the first limiting hole.

5. The variable-pitch quadrotor aircraft according to claim 1, characterized in that: The opening angle of the horizontal limiting groove is 180 degrees.

6. The variable-pitch quadrotor aircraft according to claim 2, characterized in that: The fan-shaped worm gears installed on one side of two adjacent second frame arms are arranged at an angle of 90 degrees.

7. The variable-pitch quadrotor aircraft according to claim 1, characterized in that: The lift assembly comprises a blade (5) and a blade shaft, wherein the blade shaft is fixedly connected to the top of the outer arm (1), and the blade shaft is connected to the blade (5) by a bolt (6).

8. The variable-pitch quadrotor aircraft according to claim 3, characterized in that: It also includes four landing gears; each landing gear is fixedly connected to the bottom of each first frame arm and is perpendicular to the first frame arm; the landing gear, the first frame arm and the fairing (2) are all hollow structures.

Images