A tilt-thrust quadcopter

Abstract

The application provides a tilt thrust four-duct aircraft, comprising: four curved ducts, which are distributed in up, down, left and right directions; a fixed frame, which is provided with four arc-shaped grooves, and the four ducts are embedded in the four arc-shaped grooves and fixed; and a duct fan is obliquely installed in each duct. The curved duct design can effectively reduce noise, and can reduce the danger that the aircraft may cause to people and objects in the surrounding environment during flight, and the safety is significantly improved compared with an open rotor configuration.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of machinery, in particular to a tilt thrust four-duct aircraft. BACKGROUND

[0002] In the field of unmanned aerial vehicles, the common structural types mainly cover open rotor configuration and short duct structure. The open rotor configuration is a traditional and widely used multi-rotor layout, Figure 1 For the schematic diagram of the open rotor configuration unmanned aerial vehicle in the prior art, as shown in Figure 1 The open rotor configuration causes the noise source to be directly exposed to the environment space, and the open structure causes the uncontrolled propagation of broadband noise, which seriously restricts the implementation effect of noise control technology in urban low-altitude scenarios. Figure 2 For the schematic diagram of the short duct structure unmanned aerial vehicle in the prior art, as shown in Figure 2 Although the short duct structure unmanned aerial vehicle can constrain the rotor airflow to a certain extent, it is still difficult to achieve the purpose of effective noise reduction due to the duct design problem.

[0003] In summary, the existing open rotor configuration and short duct structure unmanned aerial vehicles have obvious deficiencies in noise control and cannot meet the needs of complex urban low-altitude environments. Therefore, it is of great practical significance to develop a new type of unmanned aerial vehicle structure to solve the above problems. SUMMARY

[0004] The present application provides a tilt thrust four-duct aircraft to solve the noise control problem in the prior art.

[0005] A tilt thrust four-duct aircraft, comprising:

[0006] Four curved ducts, the four ducts are distributed in up-down and left-right directions;

[0007] A fixed frame is provided with four arc-shaped grooves, and the four ducts are respectively embedded in the four arc-shaped grooves and fixed;

[0008] A duct fan is respectively installed in each duct.

[0009] Further, the tilt thrust four-duct aircraft described above, the duct comprises: a downwardly open curved nozzle, an upwardly open curved air inlet pipe;

[0010] The air inlet pipe and the nozzle are coaxially connected on the airflow channel; and the duct fan is obliquely installed at the connection between the air inlet pipe and the nozzle.

[0011] Further, the tilt thrust four-duct aircraft described above, the duct further comprises a semi-annular upper fixing member and a semi-annular lower fixing member.

[0012] The turbofan is clamped and fixed by the upper and lower fixing members in an interference fit connection mode;

[0013] The upper and lower fixing members are both double-layer structures, and a cavity gap is formed between the double-layer structures, and the upper edge of the nozzle is inserted into the cavity gap;

[0014] Four nozzle protrusions are circumferentially distributed on the outer edge of the nozzle, two upper protrusions are circumferentially distributed on the outer edge of the upper fixing member, and two lower protrusions are circumferentially distributed on the lower fixing member; the two upper protrusions and the two lower protrusions correspond to the positions of the four nozzle protrusions, and are fixed as a whole by bolts.

[0015] Further, the inclined-thrust four-turbofan aircraft as described above, the turbofan comprises: a rotor, an annular channel, a motor;

[0016] A flange plate is arranged at one end of the annular channel, the upper and lower fixing members are clamped on the annular channel and are limited in the axial direction by the flange plate; and the motor is arranged in the nozzle.

[0017] The width of the flange plate is consistent with the width of the upper and lower fixing members.

[0018] Further, the inclined-thrust four-turbofan aircraft as described above, wing plates are arranged on both side edges of the upper and lower fixing members, and the upper and lower fixing members are fixed as a whole by bolt holes arranged on the wing plates.

[0019] Two nozzle clamping grooves are arranged on the outer circumference of the nozzle, and two air inlet pipe clamping grooves are arranged at corresponding positions on the outer circumference of the air inlet pipe.

[0020] Part of the wing plate is clamped into the nozzle clamping groove, and part of the wing plate is clamped into the air inlet pipe clamping groove.

[0021] Bolt holes are arranged on the wing plate, the nozzle clamping groove, and the air inlet pipe clamping groove, and the wing plate, the nozzle clamping groove, and the air inlet pipe clamping groove are fixed as a whole by bolts and the bolt holes arranged thereon.

[0022] Further, the inclined-thrust four-turbofan aircraft as described above, the opening at the upper part of the air inlet pipe is in an inverted trumpet shape.

[0023] Further, the inclined-thrust four-turbofan aircraft as described above, the fixing frame comprises: a semi-annular air inlet pipe fixing member, a center top plate, a center bottom plate, and four landing gears made of carbon pipe materials.

[0024] The center top plate and the center bottom plate are arranged in parallel, one end of each landing gear is fixedly connected with the center top plate in an interference fit mode, and the other end is fixedly connected with the center bottom plate in an interference fit mode.

[0025] The four landing gears are arranged in an inclined state and are symmetrically arranged left and right and up and down, a containing space suitable for the shape and size of the battery is constructed through the center area of the four landing gears, and the battery is fixed in the middle position in a clamping mode.

[0026] An annular groove with the same width as the air inlet pipe fixing piece is arranged on the air inlet pipe, the air inlet pipe fixing piece and the semi-annular fixing piece on the center top plate are embedded in the annular groove, and are fixed as a whole through nylon bolts.

[0027] Further, the inclined thrust four-duct aircraft described above further comprises a flight control and a flight control base.

[0028] The flight control base is a hollow structure, the battery is embedded in the flight control base, and the flight control is adhered to the flight control base through double-sided foam.

[0029] Further, the inclined thrust four-duct aircraft described above further comprises an upper nozzle fixing piece and a lower nozzle fixing piece.

[0030] The inclined ducts are clamped and fixed through the upper nozzle fixing piece and the lower nozzle fixing piece, and the lower nozzle fixing piece is fixed on the center bottom plate.

[0031] The upper nozzle fixing piece, the lower nozzle fixing piece and the center bottom plate are all hollow structures.

[0032] Further, the inclined thrust four-duct aircraft described above, the center bottom plate is in a cross-shaped structure, and each duct corresponds to a support installation position on the center bottom plate.

[0033] The inclined thrust four-duct aircraft provided by the application has the advantages that: through the curved duct design, on the one hand, the noise is effectively reduced, and on the other hand, the curved duct wraps the duct fan inside, forms physical protection, reduces the danger that the aircraft may cause to the surrounding environment during flight, and the safety is significantly improved compared with the open rotor configuration. Moreover, the inclined installation of the duct fan optimizes the mass center distribution of the whole machine, the rigidity of the annular layout fixing frame is large, the influence of vibration on flight is reduced, the stability of the aircraft during flight is enhanced, and the aircraft can better adapt to the complex environment of urban low altitude. BRIEF DESCRIPTION OF DRAWINGS

[0034] Figure 1 It is a schematic diagram of the open rotor configuration unmanned aerial vehicle in the prior art;

[0035] Figure 2 A schematic diagram of a short-duct structure unmanned aerial vehicle in the prior art;

[0036] Figure 3 A schematic diagram of a tilting-thrust four-duct aerial vehicle structure provided by the present application;

[0037] Figure 4 A side view cross-sectional diagram of one of the ducts of the tilting-thrust four-duct aerial vehicle provided by the present application;

[0038] Figure 5 A schematic diagram of the explosion structure of one of the ducts of the tilting-thrust four-duct aerial vehicle provided by the present application;

[0039] Figure 6 A schematic diagram of a fixing frame structure provided by the present application with a battery installed;

[0040] Figure 7 A schematic diagram of a fixing frame structure provided by the present application with a battery and a flight control installed;

[0041] Figure 8 A schematic diagram of a tilting-thrust four-duct aerial vehicle structure provided by the present application;

[0042] Figure 9 A schematic diagram of the position of the lower fixing member and the wing plate;

[0043] Reference signs:

[0044] 1 - upper fixing member; 2 - duct fan; 3 - nozzle, 4 - lower fixing member, 5 - air inlet pipe; 6 - nozzle upper fixing member, 7 - nozzle lower fixing member; 8 - landing gear, 9 - center bottom plate; 10 - air inlet pipe fixing member, 11 - flight control, 12 - flight control base, 13 - battery, 14 - center top plate, 15 - duct;

[0045] 113 - upper protrusion, 41 - lower protrusion, 42 - wing plate, 31 - nozzle protrusion, 32 - nozzle clamping groove, 51 - air inlet pipe clamping groove;

[0046] 21 - rotor, 22 - annular channel, 23 - motor, 24 - flange plate. DETAILED DESCRIPTION

[0047] To make the objectives, technical solutions and advantages of the present application clearer, the technical solutions in the present application will be described below in connection with the drawings in the present application. Obviously, the described embodiments are only some of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the scope of protection of the present application.

[0048] Figure 3This is one of the structural schematic diagrams of the tilt-thrust quadruped aircraft provided by the present invention. Figure 4 A side cross-sectional view of one of the ducts of the tilt-thrust four-duct aircraft provided by the present invention, as shown below. Figure 3 , Figure 4 As shown, it includes: four curved ducts 15, which are distributed in the up, down, left and right directions; a fixing frame with four arc-shaped grooves, into which the four ducts 15 are respectively embedded and fixed; and a duct fan 2 installed at an angle in each duct 15.

[0049] Specifically, four curved ducts 15 are distributed in the vertical, horizontal, and vertical directions, forming a ring layout and secured by the arc-shaped grooves of the mounting bracket, making the overall airframe a unified structure. This ring structure improves overall rigidity and reduces vibrations caused by the operation of the motors and propellers during flight. Furthermore, the curved duct design, compared to short ducts or open rotor configurations, is longer, forming a relatively closed or semi-closed annular cavity. This effectively blocks the wideband noise (especially high-frequency tip vortex noise) generated by the high-speed rotation of the ducted fan 2 from radiating freely in all directions, better meeting the low-noise requirements of urban low-altitude environments. In addition, since the ducted fan 2 is installed at an angle within each duct 15, the angled design can control the longitudinal dimensions of the airframe while maintaining the flow channel length, optimizing the overall center of gravity distribution.

[0050] When the ducted fan 2 is working, the airflow enters from above the duct 15, passes through the ducted fan 2, and exits from the bottom of the duct, generating thrust. Because the duct 15 is curved and the ducted fan 2 is installed at an angle, the thrust direction is not vertical. Combined with the layout of the four ducts in different positions, various flight maneuvers of the aircraft, such as ascent, descent, translation, and yaw, can be achieved by adjusting the speed of each ducted fan and other parameters, utilizing the vector change of thrust.

[0051] In addition, lightweight connectors such as nylon bolts can be used to connect the mounting frame to the duct and to fix the internal components of the duct. This ensures the strength of the connection while achieving a lightweight fuselage, which is beneficial to improving the aircraft's endurance and other performance characteristics.

[0052] The four-ducted rotorcraft provided by this invention, through its curved duct design, effectively reduces noise on the one hand; on the other hand, the curved duct encloses the ducted fan 2, forming physical protection and reducing the potential danger to people and objects in the surrounding environment during flight, significantly improving safety compared to an open rotor configuration. Furthermore, the tilted installation of the ducted fan 2 optimizes the overall center of gravity distribution, and the ring-shaped fixed frame has high rigidity, reducing the impact of vibration on flight and enhancing the aircraft's stability during flight, enabling it to better adapt to the complex low-altitude urban environment.

[0053] Preferably,Figure 5 The schematic diagram of one of the ducts of the tilting thrust four-ducted aircraft provided by the present application is shown in the figure Figure 5 As shown in the figure, the duct 15 comprises an open downwardly curved nozzle 3, an open upwardly curved air inlet pipe 5, the air inlet pipe 5 and the nozzle 3 are coaxially connected at the air flow passage, and the duct fan 2 is obliquely installed at the connection of the air inlet pipe 5 and the nozzle 3.

[0054] Specifically, the single duct 15 is composed of an open downwardly curved nozzle 3 and an open upwardly curved air inlet pipe 5, which are coaxially connected at the air flow passage to form a complete air flow path. The duct fan 2 is obliquely installed at the connection of the two, and the installation angle is realized through the cooperation of the nozzle 3 and the air inlet pipe 5, which constitutes an integrated air flow passage of "air inlet pipe-duct fan-nozzle". The air flow enters from the open upward air inlet pipe 5, is guided to complete the first turning, and then flows into the obliquely installed duct fan 2. The duct fan 2 drives the air flow to enter the nozzle 3, and the nozzle 3 realizes the second turning of the air flow through the curved design, and finally discharges from the open downward nozzle to generate directional thrust. The curved design of the nozzle 3 and the air inlet pipe 5 prolongs the overall length of the duct, forming a semi-closed cavity. The long duct completely wraps the duct fan 2, forming an acoustic barrier to block the wideband noise (especially the high-frequency tip vortex noise) generated by the high-speed rotation of the fan from freely radiating to the outside, solving the defects of noise exposure of open rotors and the inability of short ducts to achieve acoustic noise reduction.

[0055] Compared with the existing short duct or open rotor structure, the tilting thrust four-ducted aircraft provided by the present application has a longer duct cavity formed by the curved and lengthened air inlet pipe 5 and nozzle 3, which can effectively reduce noise.

[0056] Preferably, the duct 15 further comprises a semi-annular upper fixing member 1 and a semi-annular lower fixing member 4; the duct fan 2 is clamped and fixed by the upper fixing member 1 and the lower fixing member 4 through interference fit connection; the upper fixing member 1 and the lower fixing member 4 are both double-layer structures, and a cavity gap is formed between the double-layer structures; the upper edge of the nozzle 3 is inserted into the cavity gap; four nozzle protrusions 31 are distributed on the outer circumferential edge of the nozzle 3, two upper protrusions 113 are distributed on the outer circumference of the upper fixing member 1, and two lower protrusions 41 are also distributed on the lower fixing member 4; the two upper protrusions 113 and the two lower protrusions 41 correspond to the positions of the four nozzle protrusions 31 respectively, and are integrally fixed by bolts.

[0057] The duct fan 2, the upper fixing member 1 and the lower fixing member 4 are processed by FDM additive manufacturing process, and the material is selected to be PLA-Aero high-performance foamed polylactic acid material, which significantly reduces the weight of the components under the premise of ensuring the structural strength.

[0058] Specifically, the semi-annular upper fixing member 1 and the lower fixing member 4 are connected to the ducted fan 2 in an upper and lower clamping manner through interference fit connection, and are connected through nylon bolts. The ducted fan is stably installed in the duct, and reliable support is provided for the work. The upper and lower fixing members have a double-layer structure, and the cavity gap is used for inserting the upper edge of the nozzle 3 to realize the connection of the nozzle and the fixing member, build the overall structure of the duct, and form a relatively stable power flow channel system of the air inlet pipe, the ducted fan, the nozzle and the like. The outer edge of the nozzle 3 is circumferentially distributed with four nozzle protrusions 31, the outer circumference of the upper fixing member 1 has two upper protrusions 113, and the lower fixing member 4 has two lower protrusions 41. The three are connected into one through the corresponding protrusion positions and bolt fixing, so that the components of the duct are connected tightly, the structural integrity is ensured, the airflow can stably pass through the duct according to the designed path, the flight attitude and power performance of the aircraft are ensured, and the like.

[0059] The inclined thrust four-duct aircraft provided by the application greatly improves the overall structural strength and rigidity of the duct through the interference fit clamping of the upper and lower fixing members on the ducted fan and the connection of the three and the nozzle through the protrusions and nylon bolts. In flight, the components are not easy to loosen and deform in the face of vibration and airflow impact caused by the rotation of the ducted fan, so that the aircraft flies more stably, and the flight safety hidden danger caused by unstable structure is reduced. Moreover, the upper and lower fixing members adopt a double-layer structure to form a cavity gap, which not only realizes the connection and fixing function of the nozzle, but also reduces the overall weight by using the cavity compared with the solid and heavy structure, which is beneficial to the lightweight design of the aircraft. In addition, the nylon bolts used in the application realize the lightweight of the fuselage while ensuring the strength.

[0060] Preferably, the ducted fan 2 comprises: a rotor 21, an annular channel 22, and a motor 23; a flange plate 24 is arranged at one end of the annular channel 22, the upper fixing member 1 and the lower fixing member 4 are clamped on the annular channel 22 and are limited in the axial direction through the flange plate 24; the motor 23 is arranged in the nozzle 3; and the width of the flange plate 24 is consistent with the width of the upper fixing member 1 and the lower fixing member 4.

[0061] Specifically, the annular channel 22 of the ducted fan serves as a main structure, and the flange plate 24 at one end clamps the annular channel 22 in cooperation with the upper fixing member 1 and the lower fixing member 4, and limits the upper and lower fixing members in the axial direction (along the length direction of the duct) by the flange plate, so that the ducted fan forms a stable axial assembly relationship with the upper and lower fixing members, the nozzle and other components, and ensures that the components do not relatively displace in the axial direction during the flight of the aircraft and the operation of the ducted fan (such as vibration caused by the rotation of the rotor driven by the motor, airflow impact and the like), maintains the stability of the overall structure of the duct, ensures the integrity of the airflow channel, and enables the airflow to pass through the duct stably, so that the ducted fan reliably generates thrust. Moreover, the width of the flange plate 24 is consistent with the width of the upper fixing member 1 and the lower fixing member 4, and when the flange plate is limited in the axial direction and clamped in the radial direction, the upper and lower fixing members can be more evenly contacted and more balanced in force with the annular channel of the ducted fan, so that the local force is not too large and the components are not deformed due to the width difference, the tightness and structural synergy of the connection between the ducted fan and the upper and lower fixing members are ensured, the ducted fan is stably installed in the duct, and the overall structural strength and stability of the duct are improved.

[0062] The tilt-thrust four-duct aircraft provided by the application multi-dimensionally restricts the position of the ducted fan in the duct through axial limitation by the flange plate and radial clamping by the upper and lower fixing members, greatly enhances the installation stability of the ducted fan, reduces problems such as structural vibration and airflow turbulence caused by loosening and displacement of the ducted fan during flight, improves the flight reliability of the aircraft, and reduces the risk of failure. Moreover, the width of the flange plate is consistent with that of the upper and lower fixing members, so that the flange plate is easy to align and position during assembly, and the installation difficulty and error are reduced.

[0063] Preferably, the tilt-thrust four-duct aircraft provided by the application is provided with wing plates 42 on both side edges of the upper fixing member 1 and the lower fixing member 4, and the upper fixing member 1 and the lower fixing member 4 are fixed as a whole through bolt holes provided on the wing plates 42; two nozzle clamping grooves 32 are provided on the outer circumference of the nozzle 3, and two air inlet pipe clamping grooves 51 are provided at the corresponding positions on the outer circumference of the air inlet pipe 5; a part of the wing plate 42 is clamped into the nozzle clamping groove 32, and a part of the wing plate 42 is clamped into the air inlet pipe clamping groove 51; bolt holes are provided on the wing plate 42, the nozzle clamping groove 32 and the air inlet pipe clamping groove 51, and the wing plate 42, the nozzle clamping groove 32 and the air inlet pipe clamping groove 51 are fixed as a whole through bolts and the bolt holes provided thereon.

[0064] Specifically, the upper fixing member 1 and the lower fixing member 4 are connected in an upper-lower "embrace" mode through the two side wing plates 42 and bolt holes, forming a clamping frame for the duct fan 2 and providing a basic support structure for the duct assembly. The wing plates 42 are partially clamped into the nozzle clamping groove 32 and the air inlet pipe clamping groove 51, and the radial limiting is realized by the clamping grooves. Then, the upper / lower fixing member, the nozzle 3 and the air inlet pipe 5 are connected in series into a rigid whole through the bolts penetrating the bolt holes of the wing plates and the clamping grooves, so as to build a complete duct housing structure and constrain the relative displacement of the components. The rigidly connected duct housing ensures that the airflow path is stable when the duct fan 2 is working, i.e. the airflow flows through the air inlet pipe 5, the duct fan and the nozzle 3, so as to avoid the leakage of the airflow and the loss of the thrust due to the loosening of the components.

[0065] The inclined thrust four-duct aircraft provided by the application greatly improves the overall rigidity of the duct assembly through the double connection of the upper-lower fixing member "embrace + wing plate clamping groove", can effectively suppress vibration during flight (especially during complex maneuvers), avoids the loss of control of the flight attitude due to structural deformation, and is suitable for the urban low-altitude strong disturbance environment.

[0066] Preferably, the opening at the upper part of the air inlet pipe 5 of the inclined thrust four-duct aircraft provided by the application is in the shape of an inverted horn.

[0067] Specifically, the airflow first enters the air inlet pipe 5 with the opening in the shape of an inverted horn, flows into the duct fan 2 after the first turning inside the air inlet pipe, and is sprayed out after the second turning inside the nozzle 3, thereby forming the main thrust. When the duct motor is working, the upper surface of the air inlet pipe 5 with the opening in the shape of an inverted horn has airflow being sucked into the duct along the wall surface, and the lower surface has no airflow flowing along the wall surface. According to Bernoulli's theorem, the higher the flow rate of the fluid, the lower the pressure. The airflow on the upper surface has a high speed and a low pressure, and the airflow on the lower surface has a low speed and a high pressure, thereby forming a pressure difference between the upper surface and the lower surface and generating additional lift.

[0068] The duct wall of the duct motor itself has an outward expansion design, and the upper fixing member 1 and the lower fixing member 4 of the duct have a hollow structure, which reduces the obstruction to the airflow in the duct and enables the airflow to smoothly flow through the outward expansion part of the duct wall. This part of the outward expansion structure also generates additional lift through a similar pressure difference principle (the difference in flow rate of the airflow causes the difference in pressure), thereby further improving the lift performance of the aircraft.

[0069] The inclined thrust four-duct aircraft provided by the application has the air inlet pipe with the opening in the shape of an inverted horn, which increases the air inlet area and can introduce more airflow in a unit of time, so as to provide more sufficient airflow source for the duct fan, make the duct fan generate more stable and strong thrust, and help to improve the lift, flight speed and other performances of the aircraft.

[0070] Figure 6 The fixed rack structure provided by the application is installed with a battery, Figure 7The fixed frame structure provided by the application is shown in the figure, which comprises a semi-annular air inlet pipe fixing member 10, a center top plate 14, a center bottom plate 9, and four landing gears 8 made of carbon pipe material. Figure 6 The center top plate 14 and the center bottom plate 9 are arranged in parallel from top to bottom, one end of each landing gear 8 is fixedly connected to the center top plate 14 in an interference fit, and the other end is fixedly connected to the center bottom plate 9 in an interference fit. The four landing gears 8 are in an inclined state and are symmetrically arranged left and right and up and down, and a space suitable for the shape and size of the battery 13 is constructed in the central area of the four landing gears 8, and the battery 13 is fixed in the middle position in a clamping manner. An annular groove with the same width as the air inlet pipe fixing member 10 is arranged on the air inlet pipe 5, the air inlet pipe fixing member 10 and the semi-annular fixing member on the center top plate 14 are embedded in the annular groove, and are fixed as a whole by nylon bolts.

[0071] The air inlet pipe fixing member 10 adopts a semi-annular thin-walled structure design with curvature. Since the fracture strength of PLA-Aero foaming material is low under the condition of thin-walled bending, PLA-CF material is selected for manufacturing.

[0072] Specifically, the center top plate 14 and the center bottom plate 9 serve as the basic support and are connected by the four inclined and symmetrically arranged landing gears 8 to form a stable frame structure. The inclined design and symmetric layout of the landing gears 8 utilize the geometric structural characteristics to construct a space suitable for the shape and size of the battery 13, and rely on the clamping manner to fix the battery in the middle position by the limiting action of the frame on the battery, thereby ensuring the stability of the battery after installation. At the same time, the semi-annular air inlet pipe fixing member 10 and the semi-annular fixing member on the center top plate 14 are spliced into a circular ring by bolts, and the adaptability of the circular ring structure to the upper part of the air inlet pipe 5 is utilized to fix the air inlet pipe 5, so that the position of the air inlet pipe 5 is stable after installation, thereby providing a reliable installation basis for the duct system.

[0073] The air inlet pipe 5 is provided with an annular groove with a width adapted to the semi-annular air inlet pipe fixing member 10, and the embedded structure of "groove + fixing member" is used to precisely embed the semi-annular fixing member of the air inlet pipe fixing member 10 and the center top plate 14 in the groove to form radial (along the circumferential direction of the air inlet pipe) limiting to limit the relative sliding of the air inlet pipe 5 and the fixing member.

[0074] The tilt thrust four-duct aircraft provided by the application is composed of a center top plate, a center bottom plate and four symmetrical tilt landing gears, has large structural rigidity and can effectively bear various loads (such as self weight, inertial force during flight, air flow force and the like) in the flight process of the aircraft. The clamping and fixing mode of the battery makes the battery firm and fixed, and the battery will not be displaced due to vibration and the like during flight, thereby ensuring stable power supply of the battery and improving the overall flight stability of the aircraft. Moreover, the battery accommodating space is constructed by tilting the layout of the landing gear, and no additional battery fixing structure is needed, so that the battery is compactly installed at the middle position while the fixing frame internal space is fully utilized, and the internal space layout of the aircraft is optimized. The splicing design of the intake pipe fixing member and the center top plate fixing member skillfully utilizes the space of the center top plate to realize fixing of the intake pipe, avoids that the intake pipe installation occupies too much external space, makes the overall structure of the aircraft more compact, is helpful to miniaturization design and improves the adaptability of the aircraft in complex environments (such as narrow space flight). Moreover, the fixing frame structure integrates the functions of battery fixing, intake pipe fixing and landing support, reduces the number of parts of the aircraft and simplifies the overall structure. Meanwhile, the structures of various parts work cooperatively to ensure stable installation of the battery, intake pipe and other key components, so that the systems of the aircraft can efficiently cooperate, thereby improving the overall performance of the aircraft.

[0075] In addition, the interference fit mode makes the landing gear and the upper and lower limiting structures closely connected, can effectively resist vibration and impact during flight, ensures the rigidity of the support frame and improves the overall stability of the aircraft during take-off and landing and flight. The landing gear is made of carbon pipe material, and carbon fiber has the characteristics of high strength and low density. In combination with the interference fit non-redundant structure design, the weight is greatly reduced while the support strength is ensured.

[0076] Further, the tilt thrust four-duct aircraft provided by the application further comprises a flight control 11 and a flight control base 12. The flight control base 12 is a hollow structure, the battery 13 is inlaid in the flight control base 12, and the flight control 11 is adhered to the flight control base 12 by double-sided foam.

[0077] Specifically, the flight control base 12 is a hollow structure, and the battery 13 is accommodated by the inlaying mode. The battery is physically protected by the base cavity to avoid collision and vibration of the battery during flight. The working process is as follows: the flight control sends a signal, the battery supplies power to the motor, the duct motor starts, air enters the duct motor through the intake pipe, and the jet pipe changes the direction of the air flow, thereby realizing flight of the aircraft.

[0078] The flexible connection foam can effectively isolate the high-frequency vibration of the duct fan, avoid false judgment of the flight control sensor (such as a gyroscope and an accelerometer) due to vibration, improve the accuracy of attitude calculation and flight control, and make the aircraft more reliable in complex maneuvers (such as urban low-altitude obstacle avoidance and precise hovering).

[0079] Further, Figure 8 The second schematic diagram of the inclined thrust four-duct aircraft structure provided by the application, Figure 9 The schematic diagram of the position of the lower nozzle fixing member and the wing plate is shown in Figure 8 、 Figure 9 The upper nozzle fixing member 6 and the lower nozzle fixing member 7 are further included, the inclined duct 15 is clamped and fixed through the upper nozzle fixing member 6 and the lower nozzle fixing member 7, and the lower nozzle fixing member 7 is fixed on the center bottom plate 9.

[0080] The upper nozzle fixing member 6, the lower nozzle fixing member 7 and the center bottom plate 9 are all hollow structures.

[0081] Specifically, the upper nozzle fixing member 6 and the lower nozzle fixing member 7 clamp the inclined duct 15 in an up-down clamping manner, the protrusions on the left and right sides of the two are matched with the protrusions of the duct assembly (the nozzle 3 and the air inlet pipe 5) to form radial limiting to ensure that the duct does not displace in the horizontal direction. The "runway circular protrusion" at the bottom of the lower nozzle fixing member 7 is matched with the groove on the center bottom plate 9 to realize transverse limiting in the front-back and left-right directions; at the same time, the lower nozzle fixing member 7 is connected with the center bottom plate 9 through nylon bolts to complete axial limiting in the up-down direction, so as to finally stably fix the duct 15 on the center bottom plate 9 and form a three-dimensional constraint system of "radial + transverse + axial". In addition, the upper nozzle fixing member 6, the lower nozzle fixing member 7 and the center bottom plate 9 adopt a hollow structure, which removes redundant materials while retaining key connection parts (such as protrusions and screw holes), so as to not only meet the structure supporting and fixing functions, but also greatly reduce the weight. The hollow design does not affect the matching relationship between parts, the groove of the upper nozzle fixing member 6 can still be precisely connected with the protrusions of the nozzle 3 and the air inlet pipe 5, and the connection strength of the lower nozzle fixing member 7 and the center bottom plate 9 is also guaranteed through the bolts and the protrusion structure, so as to realize the balance of "structural strength and light weight".

[0082] Further, the center bottom plate 9 is in a cross shape structure, and each duct corresponds to a support installation position on the center bottom plate 9.

[0083] Specifically, the cross-shaped center bottom plate can extend in four directions around the center, each extension part corresponds to a duct to form a "support installation position", which can structurally assist in supporting and positioning the duct, cooperates with the air inlet pipe fixing member and the like to guarantee the stability of the duct after installation, and emphasizes the support function of the duct on the center bottom plate.

[0084] In summary, the four-duct aircraft provided by the present application breaks through the limitations of traditional unmanned aerial vehicles from four dimensions of noise control, maneuverability, structural stability and space optimization, and through the collaborative design of "structure-function-environment adaptation", the aircraft is more suitable for the demand of low noise, high safety and strong stability in the complex environment of urban low altitude, specifically:

[0085] 1. By the bending design and combination of the inlet pipe and the nozzle, the overall length of the duct is longer than that of the conventional duct, and the duct motor is wrapped in the middle of the inlet pipe and the nozzle to form an integrated airflow channel of "inlet pipe-duct motor-nozzle". The long duct forms a closed or semi-closed annular cavity, completely wrapping the rotor (duct fan), using the cavity structure as an acoustic barrier to directly block the wideband noise (especially high-frequency tip vortex noise) generated by the high-speed rotation of the rotor from freely radiating to the outside, thereby inhibiting the spread of noise from the transmission path. Therefore, the present application can significantly reduce noise and meet the demand for low noise in urban low altitude environment.

[0086] 2. The nozzle adopts an upward opening design (non-vertical downward), and the upward opening generates a lateral component (lateral force perpendicular to the vertical direction) of the rotor lift vector, which naturally forms a yaw control moment without the need for additional complex actuators (such as rudders, tail rotors) to achieve yaw control. Therefore, the complex actuators are eliminated, the structure is simplified and the weight is reduced, and the response speed and stability of the yaw control are improved, which is more suitable for the attitude adjustment demand in the complex environment of urban low altitude.

[0087] 3. The frame adopts a ring-shaped integrated configuration, which is composed of a ring-shaped bottom plate, a top plate and a duct support frame, instead of a conventional cross frame. The ring-shaped structure has high integrity, and the bottom plate, the top plate and the duct support frame form a continuous rigid frame, which has stronger anti-deformation ability than the dispersed connection of the cross frame, and can effectively offset the vibration energy generated by the motor and the propeller during flight. Therefore, the present application has higher overall rigidity, smaller deformation during flight, reduces the interference of vibration on the flight control and sensors, improves the structural stability, prolongs the service life of the whole machine, and adapts to the multi-duct working scene with high frequency vibration.

[0088] 4. The duct fan is installed obliquely between the inlet pipe and the nozzle, instead of vertically, which controls the longitudinal size of the machine body while maintaining the length of the flow channel. The oblique installation changes the spatial angle of the duct, shortens the projection size of the machine body in the longitudinal direction (front and rear direction) under the premise of ensuring the length of the airflow channel (inlet pipe-duct-nozzle), and optimizes the distribution of the center of mass of the whole machine (makes the center of gravity closer to the center). Therefore, the longitudinal size of the machine body of the present application makes the structure more compact, improves the ability to pass through the narrow space in urban low altitude, optimizes the distribution of the center of mass, enhances the flight stability, reduces the risk of attitude loss of control, the design of the duct wrapping the fan improves the safety (avoids the exposure of the rotor), and provides a mounting basis for the acoustic noise reduction device.

[0089] It should be pointed out finally that the above embodiments are only used to illustrate the technical solutions of the present application, but not to limit the same; and although the present application has been described in detail with reference to the foregoing embodiments, it should be appreciated by those skilled in the art that the technical solutions recorded in the foregoing embodiments can be modified, or some technical features thereof can be replaced equivalently; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A tilt-thrust quadruped aircraft, characterized in that, include: Four curved culverts (15) are distributed in the vertical, horizontal and vertical directions; A fixing frame is provided with four arc-shaped grooves, and the four ducts (15) are respectively embedded in the four arc-shaped grooves and fixed. In each duct (15), a duct fan (2) is installed at an angle. The duct (15) includes: a nozzle (3) with its opening curved downwards and an air intake pipe (5) with its opening curved upwards. The intake pipe (5) and the nozzle (3) are coaxially connected in the airflow channel; the duct fan (2) is installed at an angle at the connection between the intake pipe (5) and the nozzle (3); the opening at the top of the intake pipe (5) is in the shape of an inverted trumpet. The duct (15) also includes a semi-circular upper fixing member (1) and a semi-circular lower fixing member (4). The ducted fan (2) is clamped and fixed by the upper fixing member (1) and the lower fixing member (4) through an interference fit connection; The upper fixing member (1) and the lower fixing member (4) are both double-layer structures, and a cavity gap is formed between the double-layer structures. The upper edge of the nozzle (3) is inserted into the cavity gap; the opening of the nozzle (3) is upturned. Four nozzle protrusions (31) are distributed around the outer edge of the nozzle (3), two upper protrusions (113) are distributed around the outer circumference of the upper fixing member (1), and two lower protrusions (41) are also distributed on the lower fixing member (4); the two upper protrusions (113) and the two lower protrusions (41) correspond to the positions of the four nozzle protrusions (31) respectively, and are fixed together by bolts; The ducted fan (2), upper fixing part (1), and lower fixing part (4) are all made of PLA-Aero expanded polylactic acid material and processed by FDM additive manufacturing process.

2. The tilt-thrust quadruped aircraft according to claim 1, characterized in that, The ducted fan (2) includes: rotor (21), annular channel (22), and motor (23); A flange (24) is provided at one end of the annular channel (22), and the upper fixing member (1) and the lower fixing member (4) are clamped on the annular channel (22) and are axially limited by the flange (24); the motor (23) is placed inside the nozzle (3); The width of the flange (24) is the same as the width of the upper fixing member (1) and the lower fixing member (4).

3. The tilt-thrust quadruped aircraft according to claim 1, characterized in that, Wing plates (42) are provided on both sides of the upper fixing member (1) and the lower fixing member (4), and the upper fixing member (1) and the lower fixing member (4) are fixed together by bolt holes provided on the wing plates (42); Two nozzle slots (32) are provided on the outer circumference of the nozzle (3), and two air inlet slots (51) are provided on the corresponding positions on the outer circumference of the air inlet pipe (5). A portion of the wing plate (42) is inserted into the nozzle slot (32), and a portion is inserted into the air intake slot (51); Bolt holes are provided on the wing plate (42), nozzle slot (32), and air intake slot (51). The wing plate (42), nozzle slot (32), and air intake slot (51) are fixed together with the bolt holes provided on them by bolts.

4. The tilt-thrust quadruped aircraft according to any one of claims 1-3, characterized in that, The mounting frame includes: a semi-circular intake pipe mounting component (10), a central top plate (14), a central bottom plate (9), and four landing gears (8) made of carbon fiber. The central top plate (14) and the central bottom plate (9) are arranged parallel to each other vertically. Each landing gear (8) is fixedly connected to the central top plate (14) at one end by an interference fit and to the central bottom plate (9) at the other end by an interference fit. The four landing gears (8) are all tilted and symmetrically arranged on the left, right and up and down. The central area of ​​the four landing gears (8) is used to construct a space that accommodates the shape and size of the battery (13) and fixes the battery (13) in the middle position by snapping. An annular groove with the same width as the air intake pipe fixing member (10) is provided on the air intake pipe (5). The air intake pipe fixing member (10) and the semi-annular fixing member on the central top plate (14) are embedded in the annular groove and fixed together by nylon bolts. The intake pipe fixture (10) is made of PLA-CF material.

5. The tilt-thrust quadruped aircraft according to claim 4, characterized in that, It also includes a flight controller (11) and a flight controller base (12); The flight controller base (12) has a hollow structure, the battery (13) is embedded in the flight controller base (12), and the flight controller (11) is attached to the flight controller base (12) by double-sided foam adhesive.

6. The tilt-thrust quadruped aircraft according to claim 5, characterized in that, It also includes the upper nozzle fixing component (6) and the lower nozzle fixing component (7); The inclined duct (15) is clamped and fixed by the upper nozzle fixing member (6) and the lower nozzle fixing member (7); the lower nozzle fixing member (7) is fixed on the central base plate (9); The nozzle upper fixing part (6), nozzle lower fixing part (7), and center base plate (9) are all hollow structures made of carbon fiber plate; the center top plate is processed by fused deposition modeling additive manufacturing process and the material is PLA-CF.

7. The tilt-thrust quadruped aircraft according to claim 6, characterized in that, The central base plate (9) has a cross-shaped structure, and each duct corresponds to a support installation position on the central base plate (9).

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