A structural and functional integrated main shaft for a coaxial rotor aircraft

Abstract

A main shaft with integrated structure and function for a coaxial rotor aircraft belongs to the field of aircraft design. The main shaft parts are integrated with cables, weak current devices, shock pads and part of the power supply and are designed and manufactured in an integrated manner. The present invention is actually applied to small and medium-sized coaxial twin-rotor drones and other products that have requirements for mechanical structure, structural strength and stiffness, and assembly and matching of structural parts and power cables. The product is designed as an integrated whole, and the assembly of cables, separation of strong and weak electricity, and signal shielding are completed in the manufacturing stage. Parts of the circuit board are functionally integrated with the main shaft, and the time-consuming and cumbersome parts to be assembled are integrally solidified with the main shaft in the manufacturing stage, reducing the transmission of structural vibration and assembly time; the main shaft structural stiffness and strength can be designed in different regions, further reducing the weight of the main shaft, improving the compactness of the structure of small and medium-sized coaxial twin-rotor drones, and greatly reducing assembly and maintenance time.

Description

Technical Field

[0001] The invention belongs to the field of aircraft design, and in particular relates to a main shaft with integrated structure and function for a coaxial rotor aircraft. Background Art

[0002] Coaxial twin-rotor drones generate lift through the rotation of the upper and lower propellers. The positive rotation of the propeller overcomes its own reverse torsion. It has the advantages of compact structure, symmetrical aerodynamic characteristics, high hovering efficiency, strong load capacity, and low noise. However, due to the external force transmission route cut off by the rotation of the upper and lower propellers, the overall force transmission path of the coaxial rotor drone is single, and all cables need to be assembled from the inside of the main shaft. As the only main load-bearing component in the overall structure, the main shaft of the coaxial rotor drone plays the role of structural bearing, component connection and cable assembly path. The main shaft of the currently commonly used small and medium-sized coaxial rotor drone is a hollow metal pipe. The wall thickness of the pipe is selected according to the load and structural requirements of the drone. The screw holes and the holes for the cable to pass through are drilled on the pipe according to the installation position of the components, and the equipment is installed and the cables are installed and welded. At present, the assembly and maintenance steps of coaxial twin-rotor drones are very cumbersome, and the installation sequence is also required to be high. When installing the equipment, the cables need to be combed and carefully passed through the cable holes on the shaft. The cables need to be installed simultaneously with the relevant equipment, and the length needs to be debugged and controlled simultaneously. An appropriate amount of cable length margin needs to be left to facilitate the adjustment of the installation position. In later maintenance, the coaxial twin-rotor drone components are installed in a compact layout, and the cables extend throughout various parts. The damage of local parts often requires the disassembly of all parts. At the same time, in order to prevent cable wear, all cables also need to be pulled out. After the parts are repaired and replaced, they need to be reassembled and debugged, which greatly reduces the maintenance of the coaxial twin-rotor drone.

[0003] As the power, size and functional requirements of coaxial rotor drones increase, the propeller size of coaxial rotors also needs to increase, and the number of cables required for assembly and the thickness and diameter of the cables also increase further. The strong and weak current signal lines of the power supply equipment and the control, digital transmission and image transmission equipment are all installed in the hollow pipe of the main shaft. When the drone is in operation, the alternating current generated by the power line will affect other weak current control signals. The increase in the size and power of the drone will make the vibration environment of the structure more severe. As the only main load-bearing component in the overall structure, the increase in the weight and vibration environment of the main shaft further increases the need for the strength and stiffness of the main shaft structure, and increases the difficulty of cable assembly and subsequent maintenance. The main shaft structure of existing small and medium-sized coaxial rotor drones is still a drilling and positioning processing method for hollow pipes and mounting components. The efficiency of component assembly and subsequent debugging and maintenance is low, and it is impossible to further reflect the advantages of the use of coaxial rotor drones.

[0004] At present, the main shaft design and manufacturing of small and medium-sized coaxial rotor UAVs still use a hollow metal (aluminum alloy or steel, etc.) pipe with equal diameters at the top and bottom. Positioning holes are drilled according to the position of the installation components and the position of the cable entry and exit. At the same time, a lathe is used to carve out a slot on the outer surface of the main shaft to facilitate the installation of the stop component. During the assembly and later debugging of parts, the replacement and maintenance of a single part requires the re-welding, disassembly, and assembly of each component and cable. With the increase in the size and load power of drones, the contradictions in the design, assembly and maintenance of the main shaft structure strength and stiffness, and the position of parts are becoming more and more prominent. The existing coaxial rotor UAV main shaft design makes the overall structure poor in installability and maintainability, and cannot further reflect the advantages of the use of coaxial rotor UAVs.

[0005] In the design of existing coaxial rotor UAVs, the main structural layout is that the middle part is the power assembly, including the reduction motor or direct drive motor, shock pad, hub, and propeller components; the lower part is the control assembly, including the swash plate, servo and flight control board, data transmission, and image transmission (camera) components; other components such as batteries and loads can be used as the center of gravity adjustment components of the whole. However, no matter what layout form and center of gravity position is adopted, the main shaft is the only main load-bearing structure and cable path of the whole structure, which will transfer the vibration and heat of the power part to other components. The existing structural design can solve some problems to a certain extent by lightweighting other structures, adding damping materials to reduce vibration, and selecting high-quality thin cables. However, the existing designs cannot remove the main shaft structure, cannot effectively reduce the overall difficulty of assembly and maintenance, and cannot fundamentally solve the problem of the main shaft components.

[0006] The present invention aims to solve the problems of difficult assembly of components such as cables, flight vibration and single force transmission path in the design, assembly and later maintenance of coaxial rotor UAVs by designing the main shaft structure through a functional and structural integrated design and manufacturing method, thus solving the problems of difficult assembly and maintenance of components such as cables and flight vibration of the body structure during flight. Summary of the invention

[0007] The main shaft functional structure of the coaxial rotor UAV proposed in the present invention integrates the main shaft parts with cables, weak current devices, shock pads and part of the power supply for integrated design and manufacturing, which can greatly reduce the difficulty and time of assembling parts, improve the strength and stiffness of the overall structure, and reduce the transmission of structural vibration, thus facilitating the subsequent debugging and maintenance of the UAV.

[0008] The technical solution of the present invention:

[0009] A structural and functional integrated main shaft of a coaxial rotor aircraft, the structural and functional integrated main shaft comprising an upper cable connector 1, a lower cable connector 7, a high-voltage cable 2, a low-voltage cable 3, a sensor 4, a screw pad 5, a circuit board 6, a vibration-damping column 8, an upper main shaft 9, a lower main shaft 10, a high-voltage and low-voltage cable channel 11, a first screw through hole 12, a second screw through hole 13, a limit groove 14, a cable outlet 15 and a sensor installation position 16.

[0010] The upper spindle 9 and the lower spindle 10 are connected by a shock-absorbing column 8. The upper spindle 9 and the lower spindle 10 serve as the main load-bearing structure of the entire coaxial rotor aircraft, and the shock-absorbing column 8 is used to isolate the vibration transmission on the upper spindle 9. The upper spindle 9 and the lower spindle 10 are provided with a strong and weak current cable channel 11 that is independently connected from top to bottom. The strong current cable 2 and the weak current cable 3 pass through the strong current and weak current cable channels 11 respectively, wherein the number of the strong current cables 2 and the weak current cables 3 and the size of the strong current and weak current cable channels 11 can be increased or decreased according to actual needs; an upper cable connector 1 and a lower cable connector 7 are provided at both ends of the upper spindle 9 and the lower spindle 10 respectively.

[0011] The first screw through hole 12 in the middle of the upper spindle 9 is used for power system installation, and the screw pad 5 is installed inside the first screw through hole 12 to reduce the transmission of vibration generated by the power system to the spindle; the limit groove 14 is located on the outer surface of the spindle 9 and is used for the installation of limit parts such as clamping rings and retaining rings. The number, position, size and depth can be adjusted according to the actual installation position of the parts; the cable outlet 15 is a through hole located on the outer side wall of the spindle, and the cable passes through the cable outlet 15 from the cable channel to connect to the outside world. The position, number and opening size of the cable outlet 15 can be adjusted according to actual needs. The cable outlet 15 is used for the entry and exit of cables to provide power, control signals and sensor signals to electrical components such as power systems and control systems; the sensor 4 is patch installed at the sensor installation position 16 on the outer side wall of the upper spindle 9, where the number and position of the sensor 4 and the sensor installation position 16 can be adjusted according to actual needs.

[0012] The position and size of the second screw hole 13 in the middle of the lower main shaft 10 can be adjusted according to the design for the installation of other required equipment. There are platform ends on both sides of the lower main shaft 10 parallel to the cables for the installation of the circuit board 6. The cables pass through the high-voltage and low-voltage cable channels 11 and are connected to the circuit board 6. The cables pass through the high-voltage and low-voltage cable channels 11 again from the other end of the circuit board 6.

[0013] Beneficial effects of the present invention: The functional structure integrated design scheme can be used for coaxial twin-rotor unmanned aerial vehicle main shaft and other parts that require strength and stiffness of the structure and that have assembly requirements with cables, power supply and electrical components. The main implementation of the present invention is to embed cables, functional parts (shock-absorbing pads, sensors, etc.), and circuit boards into the structure according to actual use requirements during the manufacturing stage, thereby reducing the time for later assembly and maintenance. The present invention is actually applied to small and medium-sized coaxial twin-rotor unmanned aerial vehicles and other products that have assembly and matching requirements for mechanical structure, structural strength and stiffness, and structural parts and power supply cables. The present invention is designed as a whole during the design stage of the product, and the assembly of cables, separation of strong and weak electricity, and signal shielding are completed during the manufacturing stage. Part of the circuit board is functionally integrated with the main shaft, and the time-consuming and cumbersome parts of the assembly are solidified as a whole with the main shaft during the manufacturing stage, thereby reducing the transmission of structural vibration and the assembly time; the main shaft structural stiffness strength can be designed in different regions, further reducing the weight of the main shaft, improving the compactness of the structure of small and medium-sized coaxial twin-rotor unmanned aerial vehicles, and greatly reducing the assembly and maintenance time. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is the integrated main axis of the coaxial rotor UAV.

[0015] Figure 2 This is the layout diagram of the main shaft internal cables and other parts.

[0016] Figure 3 This is a structural diagram of the upper and lower main axes.

[0017] Figure 4 This is an application diagram of the upper and lower spindles of the embodiment.

[0018] In the figure: 1 upper cable connector, 2 high-voltage cable, 3 low-voltage cable, 4 sensor, 5 screw pad, 6 circuit board, 7 lower cable connector, 8 vibration damping column, 9 upper spindle, 10 lower spindle, 11 high-voltage and low-voltage cable channels, 12 first screw through hole, 13 second screw through hole, 14 limit slot, 15 cable outlet, 16 sensor installation position, 17 load, 18, power system, 19 control system and internal load components, 20 spindle. DETAILED DESCRIPTION

[0019] A structural and functional integrated main shaft of a coaxial rotor aircraft, the structural and functional integrated main shaft comprising an upper cable connector 1, a lower cable connector 7, a high-voltage cable 2, a low-voltage cable 3, a sensor 4, a screw pad 5, a circuit board 6, a vibration-damping column 8, an upper main shaft 9, a lower main shaft 10, a high-voltage and low-voltage cable channel 11, a first screw through hole 12, a second screw through hole 13, a limit groove 14, a cable outlet 15 and a sensor installation position 16.

[0020] The upper spindle 9 and the lower spindle 10 are connected by a shock-absorbing column 8. The upper spindle 9 and the lower spindle 10 serve as the main load-bearing structure of the entire coaxial rotor aircraft, and the shock-absorbing column 8 is used to isolate the vibration transmission on the upper spindle 9. The upper spindle 9 and the lower spindle 10 are provided with a strong and weak current cable channel 11 that is independently connected from top to bottom. The strong current cable 2 and the weak current cable 3 pass through the strong current and weak current cable channels 11 respectively, wherein the number of the strong current cables 2 and the weak current cables 3 and the size of the strong current and weak current cable channels 11 can be increased or decreased according to actual needs; an upper cable connector 1 and a lower cable connector 7 are provided at both ends of the upper spindle 9 and the lower spindle 10, respectively, for connecting strong and weak cables, and connected with external batteries, communication and navigation modules and other electrical components through the upper cable connector 1 and the lower cable connector 7.

[0021] The first screw through hole 12 in the middle of the upper spindle 9 is used for power system installation, and the screw pad 5 is installed inside the first screw through hole 12 to reduce the transmission of vibration generated by the power system to the spindle; the limit groove 14 is located on the outer surface of the spindle 9 and is used for the installation of limit parts such as clamping rings and retaining rings. The number, position, size and depth can be adjusted according to the actual installation position of the parts; the cable outlet 15 is a through hole located on the outer side wall of the spindle, and the cable passes through the cable outlet 15 from the cable channel to connect to the outside world. The position, number and opening size of the cable outlet 15 can be adjusted according to actual needs. The cable outlet 15 is used for the entry and exit of cables to provide power, control signals and sensor signals to electrical components such as power systems and control systems; the sensor 4 is patch installed at the sensor installation position 16 on the outer side wall of the upper spindle 9, where the number and position of the sensor 4 and the sensor installation position 16 can be adjusted according to actual needs. The position and size of the second screw hole 13 in the middle of the lower spindle 10 can be adjusted according to the design, and it is used for the installation of other required equipment. There are platform ends on both sides of the lower spindle 10 parallel to the cable, which are used for the installation of the circuit board 6. The cable passes through the strong and weak current cable channel 11 and is connected to the circuit board 6. The cable passes through the strong and weak current cable channel 11 again from the other end of the circuit board 6. The functions of the circuit board 6 may include but are not limited to high and low voltage conversion and signal processing; subsequently, according to the circuit board manufacturing process, the flexible circuit printing process is adopted to further reduce the size of the platform end. The spindle used in the coaxial twin-rotor drone is used to support the upper load 17. The related components of the power system 18 in the middle are connected to the upper spindle 9 by bolts passing through the screw pad column 5 and the first screw through hole 12. The control system and internal load components 19 in the lower part are connected to the lower spindle 10 by bolts passing through the screw pad column 5 and the second screw through hole 13. The power supply and signal transmission of the upper and lower load components can be connected through the upper cable connector 1 and the lower cable connector 7 of the spindle, and the corresponding cables are connected for communication. The integrated spindle structure reduces the transmission of vibration of the power assembly to the structure. The plug-in operation unifies the interface of the electrical equipment, reduces the coupling between devices, and facilitates assembly and maintenance.

Claims

1. A main shaft with integrated structure and function for a coaxial rotor aircraft, characterized in that: The structural and functional integrated spindle comprises an upper cable connector (1), a lower cable connector (7), a high-voltage cable (2), a low-voltage cable (3), a sensor (4), a screw pad column (5), a circuit board (6), a vibration-damping column (8), an upper spindle (9), a lower spindle (10), high-voltage and low-voltage cable channels (11), a first screw through hole (12), a second screw through hole (13), a limit groove (14), a cable outlet (15) and a sensor installation position (16); The upper spindle (9) and the lower spindle (10) are connected via a shock-absorbing column (8). The upper spindle (9) and the lower spindle (10) serve as the main load-bearing structure of the entire coaxial rotor aircraft. The shock-absorbing column (8) is used to isolate the vibration transmission on the upper spindle (9). The upper spindle (9) and the lower spindle (10) are provided with independent upper and lower through-going strong and weak current cable channels (11). The strong current cables (2) and the weak current cables (3) pass through the strong current and weak current cable channels (11) respectively. The number of the strong current cables (2) and the weak current cables (3) and the size of the strong current and weak current cable channels (11) can be increased or decreased according to actual needs. An upper cable connector (1) and a lower cable connector (7) are provided at both ends of the upper spindle (9) and the lower spindle (10). The first screw through hole (12) in the middle of the upper spindle (9) is used for installing the power system, and the screw pad column (5) is installed inside the first screw through hole (12) to reduce the transmission of vibration generated by the power system to the spindle; the limit groove (14) is located on the outer surface of the spindle (9) and is used for installing limit parts such as clamping rings and retaining rings, and its number, position and size depth can be adjusted according to the actual installation position of the parts; the cable outlet (15) is a through hole located on the outer side wall of the spindle, and the cable passes through the cable outlet (15) from the cable channel to connect to the outside, and the position, number and opening size of the cable outlet (15) can be adjusted according to actual needs. The cable outlet (15) is used for the cable to pass in and out, and provide power, control signals and sensor signals to the power system and control system electrical components; the sensor (4) is installed on the sensor installation position (16) on the outer side wall of the upper spindle (9), wherein the number and position of the sensor (4) and the sensor installation position (16) can be adjusted according to actual needs; The position and size of the second screw through hole (13) in the middle of the lower main shaft (10) can be adjusted according to the design for installation of other required equipment. The lower main shaft (10) has platform ends on both sides parallel to the cables for installation of the circuit board (6). The cables pass through the high-voltage and low-voltage cable channels (11) and are connected to the circuit board (6). The cables pass through the high-voltage and low-voltage cable channels (11) again from the other end of the circuit board (6).

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