Power and transmission system for unmanned aerial vehicle and low altitude aircraft

Abstract

The application discloses a power and transmission system for a UAV and a low-altitude aircraft, and relates to the technical field of low-altitude safety, and aims to solve the low-altitude safety problems of the prior art, such as serious transmission of high-frequency torsional vibration of an engine, great assembly difficulty of coaxial centering, incompatibility of a damping clutch and a power generation structure, and low success rate of secondary restart after engine flameout in the air. The application comprises an engine, a rubber torsional damper, a clutch system, a gearbox, a laminated flexible coupling and a generator. The output end of the rubber torsional damper is connected with the input end of the clutch system. The clutch system transmits power to the gearbox through a belt and transmits power to the generator through the laminated flexible coupling. The engine, the rubber torsional damper, the clutch system and the generator are coaxially and linearly arranged. The application realizes vibration attenuation, flexible compensation of coaxial deviation and collaborative arrangement of the damping clutch and the power generation structure, and improves the success rate of secondary restart of the UAV after engine flameout in the air and the low-altitude flight safety.

Description

Technical Field

[0001] This invention relates to the field of low-altitude safety technology, and in particular to a power and transmission system for unmanned aerial vehicles and a low-altitude aircraft. Background Technology

[0002] In low-altitude flight missions, the safety and reliability of the power transmission and power generation systems of coaxial unmanned aerial vehicles (UAVs) are core elements for ensuring flight safety. In existing technologies, the power output from the engine is typically transmitted directly to the clutch and gearbox via a rigid main shaft, synchronously driving the generator to supply power to the onboard equipment.

[0003] However, in the existing technology, the power transmission and power generation systems of drones mainly have the following safety hazards for low-altitude flight: First, high-frequency torsional vibration poses a risk of attitude instability during low-altitude flight. The high-frequency torsional vibration generated during engine operation is transmitted to the entire transmission chain without attenuation through the rigid main shaft. In low-altitude, low-speed flight, continuous vibration of the fuselage can easily cause noise interference in the signals collected by flight control sensors. In severe cases, it may cause attitude control deviation. In low-altitude airspace with dense buildings, attitude deviation will directly lead to the risk of collision and crash.

[0004] Secondly, the low success rate of restarting after an in-flight engine failure poses a safety hazard. Traditional permanent magnet generators cannot actively cut off power based on operating conditions, and the generator always carries a reverse drag torque after an in-flight engine failure. Even if the clutch can disengage and cut off the mechanical load, the electrical load cannot be eliminated. The engine must overcome both mechanical and electrical resistance to complete a restart. In low-altitude flight, the restart window is extremely short, and a failed restart will directly lead to power loss and a crash, seriously threatening the safety of people and property on the ground.

[0005] Third, the power transmission system lacks adaptive safety assurance capabilities under complex low-altitude operating conditions. The existing vibration reduction structure, clutch structure, and power generation structure are designed independently and lack synergy and compatibility. Under sudden low-altitude operating conditions, it is impossible to achieve synchronous and rapid disconnection of mechanical and electrical loads, unable to provide the engine with resistance-free secondary restart conditions, and also difficult to meet the stringent space requirements of compactness and lightweight design for the power system in low-altitude flight.

[0006] Fourth, the high requirements for coaxial alignment accuracy create a structural contradiction with the harsh operating conditions at low altitudes. During low-altitude flight, engine operating conditions fluctuate dramatically, and thermal expansion and contraction as well as vibration and shock are more pronounced. The stringent requirements for coaxiality and angular accuracy of rigid connection structures are difficult to maintain for long periods within the confined engine compartment. Slight deviations are rapidly aggravated by vibrations at low altitudes, further reducing the reliability of the transmission system and increasing the probability of in-flight failure.

[0007] Therefore, there is an urgent need for a power transmission and power generation safety assurance system that can effectively attenuate high-frequency torsional vibration of the engine and compensate for coaxial deviation, while simultaneously being compatible with clutch transmission and emergency power generation functions, and significantly improving the success rate of restarting the engine after an in-flight shutdown under abnormal low-altitude flight conditions, so as to serve the overall development needs of low-altitude safety technology. Summary of the Invention

[0008] Based on the above analysis, the present invention aims to provide a power and transmission system for unmanned aerial vehicles and a low-altitude aircraft, in order to solve the low-altitude safety problems in the prior art, such as severe high-frequency torsional vibration transmission of engines, difficulty in coaxial alignment and assembly, incompatibility of vibration reduction clutch power generation structures, and low success rate of secondary restart after engine shutdown in the air.

[0009] The objective of this invention is mainly achieved through the following technical solutions: A power and transmission system for an unmanned aerial vehicle (UAV) includes an engine, a rubber torsional vibration damper, a clutch system, a gearbox, a laminated flexible coupling, and a generator. The generator is configured as an excitation-type DC generator. The power output shaft of the engine is fixedly connected to the input end of the rubber torsional vibration damper, and the output end of the rubber torsional vibration damper is fixedly connected to the input end of the clutch system. The clutch system transmits power to the gearbox via a belt, and the clutch system transmits power to the generator via the laminated flexible coupling. The engine, the rubber torsional vibration damper, the clutch system, and the generator are arranged coaxially.

[0010] Furthermore, the rubber torsional vibration damper includes an output shaft sleeve, a rubber-metal composite component, a torsional vibration damping adapter plate, radial bolts, axial bolts, and locating pins; the locating pins include axial locating pins and radial locating pins, the rubber-metal composite component is connected to the torsional vibration damping adapter plate via the axial locating pins, connected to the output shaft sleeve via the radial locating pins, connected to the torsional vibration damping adapter plate via the radial bolts, and connected to the output shaft sleeve via the axial bolts.

[0011] Furthermore, the rubber torsional damper provides coaxial compensation adjustment in both radial and angular directions, with the adjustment range being 0.3 mm to 1.0 mm.

[0012] Furthermore, the clutch system includes a clutch assembly, a left clutch bracket, an arch beam bracket, a right clutch bracket, and an I-beam plate; the clutch system is fixed to the frame via the arch beam bracket; the left clutch bracket and the right clutch bracket are respectively disposed on both sides of the clutch assembly, the arch beam bracket is disposed below the clutch assembly, and the I-beam plate is connected between the left clutch bracket and the right clutch bracket.

[0013] Furthermore, the clutch assembly includes a clutch outer cover, a clutch pulley, a clutch inner shaft, a clutch block assembly, and a clutch end cover; one end of the clutch inner shaft is fixedly connected to the output end of the rubber torsional vibration damper, and the other end is connected to the generator through the laminated flexible coupling; the clutch block assembly is disposed on the outer periphery of the clutch inner shaft, the clutch outer cover is sleeved on the outside of the clutch block assembly and fixedly connected to the clutch pulley, and the clutch end cover is disposed at the end of the clutch outer cover.

[0014] Furthermore, the clutch assembly also includes a deep groove ball bearing and a needle roller bearing; the clutch inner shaft is supported in the inner hole of the clutch pulley by the needle roller bearing, and the deep groove ball bearing is disposed between the clutch outer cover and the clutch inner shaft.

[0015] Furthermore, the clutch block assembly includes a clutch block and a coil spring; the clutch block is thrown outward against the tension of the coil spring under the action of centrifugal force and engages with the inner wall of the clutch cover.

[0016] Furthermore, the laminated flexible coupling includes a generator mounting plate, a diaphragm, an adapter plate, an intermediate shaft, and a clutch mounting plate; the generator mounting plate is fixedly connected to the input shaft end of the generator, and the clutch mounting plate is fixedly connected to the inner shaft of the clutch system.

[0017] Furthermore, the rubber-metal composite is integrally formed by vulcanization of fluororubber elastomer and aerospace aluminum alloy inner and outer rings.

[0018] A low-altitude aircraft, comprising the power and transmission system for an unmanned aerial vehicle as described above.

[0019] The technical solution of this invention can achieve at least one of the following effects: (1) This invention sets up an engine, a rubber torsional vibration damper, a clutch system, a gearbox, a laminated flexible coupling and a generator. The generator is set as an excitation type DC generator. The engine is connected to the input end of the rubber torsional vibration damper, the output end of the rubber torsional vibration damper is connected to the input end of the clutch system, the clutch system transmits power to the gearbox through a belt, and transmits power to the generator through the laminated flexible coupling. The engine, rubber torsional vibration damper, clutch system and generator are arranged coaxially. This solves the problem of low space utilization caused by the transmission of high-frequency torsional vibration through a rigid main shaft without attenuation and the independent arrangement of each subsystem in the prior art. It achieves effective attenuation of vibration in the power transmission path, and at the same time achieves the lightweight and compactness of the system.

[0020] (2) The present invention uses a rubber torsional vibration damper including an output shaft sleeve, a rubber-metal composite, a torsional vibration damping adapter plate, radial bolts, axial bolts and positioning pins. The positioning pins include axial positioning pins and radial positioning pins. The rubber-metal composite is connected to the torsional vibration damping adapter plate through the axial positioning pin, connected to the output shaft sleeve through the radial positioning pin, connected to the torsional vibration damping adapter plate through the radial bolts, and connected to the output shaft sleeve through the axial bolts. This solves the problem of accurate positioning and reliable connection between the vibration damper and the metal parts on both sides, realizes the stable combination of the elastic body and the metal parts, and realizes the structural integrity and torque transmission reliability of the vibration damper under high frequency vibration environment.

[0021] (3) The present invention includes a clutch system comprising a clutch assembly, a left clutch bracket, an arch beam bracket, a right clutch bracket and an I-beam plate. The clutch system is fixed to the frame by the arch beam bracket. The left clutch bracket and the right clutch bracket are respectively set on both sides of the clutch assembly. The I-beam plate is connected between the two brackets. This invention solves the problem of insufficient structural rigidity of the clutch system during high torque transmission and achieves stable support for the clutch assembly.

[0022] (4) The present invention is fixedly connected to the output end of the rubber torsional vibration damper at one end of the inner shaft of the clutch and connected to the generator at the other end through the laminated flexible coupling. The clutch block assembly is located on the outer periphery of the inner shaft of the clutch, and the clutch cover is fitted on the outside of the clutch block assembly and fixedly connected to the clutch pulley. This solves the problem that the three modules of vibration damping, clutch and power generation are structurally dispersed and cannot be integrated along the power flow direction, and realizes the linear integration of the three functional modules and the smooth transmission of torque.

[0023] (5) The present invention uses a clutch block assembly including a clutch block and a helical spring. Under the action of centrifugal force, the clutch block overcomes the tension of the helical spring and is thrown outward to engage with the inner wall of the clutch cover to realize power transmission. This solves the problem that the clutch cannot automatically cut off the mechanical load according to the speed. It realizes the automatic clutch function of disengaging the clutch at low speed to start the engine under no-load, automatically engaging to drive the rotor at high speed, and automatically cutting off the mechanical load when the speed drops sharply.

[0024] In this invention, the above-described technical solutions can be combined with each other to achieve more preferred combinations. Other features and advantages of this invention will be set forth in the following description, and some advantages may become apparent from the description or be learned by practicing the invention. The objects and other advantages of this invention can be realized and obtained from what is particularly pointed out in the description and drawings. Attached Figure Description

[0025] The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Throughout the drawings, the same reference numerals denote the same parts.

[0026] Figure 1 This is one of the overall structural schematic diagrams of the power and transmission system for an unmanned aerial vehicle according to Embodiment 1 of the present invention; Figure 2 This is a second schematic diagram of the overall structure of the power and transmission system for an unmanned aerial vehicle according to Embodiment 1 of the present invention; Figure 3 This is one of the overall structural diagrams of the laminated flexible coupling for the power and transmission system of an unmanned aerial vehicle according to Embodiment 1 of the present invention; Figure 4 This is a front view of the clutch system for the power and transmission system of an unmanned aerial vehicle according to Embodiment 1 of the present invention; Figure 5 This is the second overall structural diagram of the laminated flexible coupling for the power and transmission system of an unmanned aerial vehicle (UAV) according to Embodiment 1 of the present invention. Figure 6 This is one of the overall structural diagrams of the clutch system for the power and transmission system of an unmanned aerial vehicle according to Embodiment 1 of the present invention; Figure 7 This is the second overall structural diagram of the clutch system for the power and transmission system of an unmanned aerial vehicle according to Embodiment 1 of the present invention; Figure 8 This is a top view of the clutch system for the power and transmission system of an unmanned aerial vehicle according to Embodiment 1 of the present invention; Figure 9 This is a front view of the clutch assembly for the power and transmission system of an unmanned aerial vehicle according to Embodiment 1 of the present invention; Figure 10 This is a cross-sectional view of the clutch system for the power and transmission system of an unmanned aerial vehicle according to Embodiment 1 of the present invention. Figure 11 This is a top view of the clutch block assembly for the power and transmission system of an unmanned aerial vehicle according to Embodiment 1 of the present invention; Figure 12 This is a side view of a rubber torsional vibration damper for the power and transmission system of an unmanned aerial vehicle according to Embodiment 1 of the present invention; Figure 13 This is one of the structural schematic diagrams of a rubber torsional vibration damper for the power and transmission system of an unmanned aerial vehicle according to Embodiment 1 of the present invention; Figure 14 This is a second schematic diagram of the structure of a rubber torsional vibration damper for the power and transmission system of an unmanned aerial vehicle (UAV) according to Embodiment 1 of the present invention. Figure 15 This is a cross-sectional view of a rubber torsional vibration damper for the power and transmission system of an unmanned aerial vehicle according to Embodiment 1 of the present invention.

[0027] Figure label: 1-Laminated flexible coupling; 11-Generator mounting plate; 12-Diaphragm; 13-Adapter plate; 14-First screw assembly; 15-Intermediate shaft; 16-Second screw assembly; 17-Clutch mounting plate; 2-Clutch system; 21-Clutch assembly; 211-Clutch housing; 212-Deep groove ball bearing; 213-Clutch pulley; 214-Clutch end cover; 215-Clutch inner shaft; 216-Clutch block assembly; 2161-Clutch block; 2162-Coil spring; 217-Needle roller bearing; 218-Flange bolt; 22-Left side clutch bracket; 23-Arch beam bracket; 24-Belt; 25-Right side clutch bracket; 26-I-beam plate; 3-Rubber torsional vibration damper; 31-Output shaft sleeve; 32-Rubber-metal composite part; 33-Torsion damping adapter plate; 34-Radial bolt; 35-Axial bolt; 36-Positioning pin; 4-Generator; 5-Gearbox; 6-Engine; 7-Frame. Detailed Implementation

[0028] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings. These embodiments are merely illustrative of the principles of the invention and are not intended to limit the scope of protection of the invention. The scope of protection of the present invention is defined by the claims.

[0029] Example 1 This embodiment aims to provide a power and transmission system for unmanned aerial vehicles (UAVs) to solve the low-altitude safety problems in existing UAV power transmission and power generation systems, such as severe vibration transmission, high requirements for coaxial alignment, incompatibility between vibration reduction clutch power generation structures, and low success rate of secondary restart after in-flight engine shutdown.

[0030] like Figure 1 and Figure 2 As shown, the power and transmission system includes an engine 6, a rubber torsional damper 3, a clutch system 2, a gearbox 5, a laminated flexible coupling 1, and a generator 4. The generator system is coaxially and compactly arranged within the unmanned aerial vehicle (UAV) cabin and is fixedly mounted via a frame 7.

[0031] Specifically, the power output shaft of engine 6 is fixedly connected to the input end of rubber torsional damper 3. The output end of rubber torsional damper 3 is fixedly connected to the input end of clutch system 2. Clutch system 2 transmits power to gearbox 5 via belt 24, and clutch system 2 transmits power to generator 4 via laminated flexible coupling 1.

[0032] Furthermore, to address the issue of undamped transmission of high-frequency torsional vibrations from the engine via a rigid spindle, such as... Figures 12 to 15As shown, the rubber torsional vibration damper 3 includes an output shaft sleeve 31, a rubber-metal composite part 32, a torsional vibration damping adapter plate 33, a radial bolt 34, an axial bolt 35, and a locating pin 36.

[0033] Specifically, such as Figure 15 As shown, the positioning pin 36 includes an axial positioning pin and a radial positioning pin. The rubber-metal composite 32 is connected to and positioned by the torsional vibration damping adapter plate 33 through the axial positioning pin, and the rubber-metal composite 32 is connected to and positioned by the output shaft sleeve 31 through the radial positioning pin.

[0034] The rubber-metal composite 32 is connected to the torsional damping adapter plate 33 by radial bolts 34, and the rubber-metal composite 32 is connected to the output shaft sleeve 31 by axial bolts 35.

[0035] Preferably, the rubber-metal composite part 32 is integrally formed by vulcanization of fluororubber elastomer and aerospace aluminum alloy inner and outer rings.

[0036] More preferably, the rubber torsional damper 3 provides coaxial compensation adjustment in both radial and angular directions, with a compensation range of 0.3mm-1.0mm, and a compensation of 0.6mm in the standard embodiment.

[0037] When in use, the rubber torsional vibration damper 3 transmits torque from the output shaft of the engine 6 to the output shaft sleeve 31. After the high-frequency torsional vibration is attenuated by the elastic body of the rubber-metal composite 32, it is smoothly output to the clutch system 2 through the torsional vibration damping adapter plate 33. The instantaneous impact during engine 6 startup and shutdown is absorbed and buffered by the rubber-metal composite 32. During assembly, the elastic deformation of the rubber torsional vibration damper 3 can compensate for the radial and angular coaxial deviations between the output shaft of the engine 6 and the input end of the clutch system 2, thus relaxing the requirements for assembly alignment accuracy.

[0038] like Figure 4 As shown, the clutch system 2 includes a clutch assembly 21, a left clutch bracket 22, an arch beam bracket 23, a belt 24, a right clutch bracket 25, and an I-beam plate 26. The clutch system 2 is fixed to the frame 7 by the arch beam bracket 23.

[0039] Specifically, such as Figures 6 to 8 As shown, the left clutch bracket 22 and the right clutch bracket 25 are respectively located on both sides of the clutch assembly 21. The arch beam bracket 23 is located below the clutch assembly 21 and fixed on the frame 7. The belt 24 is mounted on the pulley of the clutch assembly 21 and connected to the gearbox 5. The I-beam plate 26 is connected between the left clutch bracket 22 and the right clutch bracket 25.

[0040] Furthermore, such as Figure 9 and Figure 10As shown, the clutch assembly 21 includes a clutch outer cover 211, a deep groove ball bearing 212, a clutch pulley 213, a clutch end cover 214, a clutch inner shaft 215, a clutch block assembly 216, a needle roller bearing 217, and flange bolts 218. The clutch inner shaft 215 is supported in the inner hole of the clutch pulley 213 by the needle roller bearing 217. One end of the clutch inner shaft 215 is fixedly connected to the output end of the rubber torsional damper 3, and the other end is connected to the generator 4 via a laminated flexible coupling 1. The clutch block assembly 216 is disposed on the outer periphery of the clutch inner shaft 215. The clutch outer cover 211 is fitted over the clutch block assembly 216 and fixedly connected to the clutch pulley 213. The deep groove ball bearing 212 is disposed between the clutch outer cover 211 and the clutch inner shaft 215. The clutch end cover 214 is disposed at the end of the clutch outer cover 211 and fixed by the flange bolts 218.

[0041] Furthermore, such as Figure 11 As shown, the clutch block assembly 216 includes a clutch block 2161 and a coil spring 2162. Under the action of centrifugal force, the clutch block 2161 overcomes the tension of the coil spring 2162 and is thrown outward, engaging with the inner wall of the clutch cover 211 to realize power transmission.

[0042] Preferably, the threshold speed for clutch triggering is 30% of the engine's rated operating speed, and the threshold speed for clutch triggering is set to 1800 rpm.

[0043] When the clutch system 2 is in use, the torque of the engine 6 is transmitted to the inner shaft 215 of the clutch via the rubber torsional damper 3. At low speeds, the clutch block 2161 remains contracted under the action of the coil spring 2162, the clutch is in the disengaged state, and the main rotor is unloaded. When the engine speed of 6 rises above 1800 rpm, the centrifugal force on the clutch block 2161 exceeds the tension of the coil spring 2162, and the clutch block 2161 is thrown outward to engage with the clutch cover 211. Power is then transmitted to the gearbox 5 via the clutch pulley 213 and the belt 24, driving the main rotor to rotate. When the engine speed of 6 drops sharply below 1800 rpm, the coil spring 2162 pulls the clutch block 2161 back, the clutch automatically disengages, and the mechanical load on the main rotor is cut off.

[0044] Furthermore, to address the issues of the permanent magnet generator's inability to actively cut off power based on operating conditions and the low success rate of restarting after an in-flight shutdown, the clutch inner shaft 215 is fixedly connected to the input shaft end of the generator 4 via a laminated flexible coupling 1.

[0045] Specifically, such as Figure 3 and Figure 5As shown, the laminated flexible coupling 1 includes a generator mounting plate 11, a diaphragm 12, an adapter plate 13, a first screw assembly 14, an intermediate shaft 15, a second screw assembly 16, and a clutch mounting plate 17. The generator mounting plate 11 is fixedly connected to the input shaft end of the generator 4, and the clutch mounting plate 17 is fixedly connected to the clutch inner shaft 215.

[0046] Two adapter plates 13 are provided, symmetrically arranged on both sides of the intermediate shaft 15. One adapter plate 13 is located between the generator mounting plate 11 and the intermediate shaft 15, and the other is located between the intermediate shaft 15 and the clutch mounting plate 17. Two diaphragms 12 are also provided, symmetrically arranged on both sides of the intermediate shaft 15. One diaphragm 12 closer to the generator mounting plate 11 is located between the generator mounting plate 11 and the adapter plate 13, and the other diaphragm 12 closer to the clutch mounting plate 17 is located between the adapter plate 13 and the clutch mounting plate 17. A first screw assembly 14 is used to connect the generator mounting plate 11 and the adapter plate 13. The diaphragm 12 closer to the generator mounting plate 11 is clamped and fixed between the generator mounting plate 11 and the adapter plate 13 by a second screw assembly 16; the diaphragm 12 closer to the clutch mounting plate 17 is clamped and fixed between the adapter plate 13 and the clutch mounting plate 17 by the second screw assembly 16.

[0047] When in use, the lamination flexible coupling 1 transmits torque via the clutch inner shaft 215 to the clutch mounting plate 17, and then via the diaphragm 12 and intermediate shaft 15 to the generator mounting plate 11, driving the rotor of the generator 4 to rotate. The lamination flexible coupling 1 compensates for minor installation misalignments between the clutch inner shaft 215 and the input shaft of the generator 4 through the elastic deformation of the diaphragm 12, isolates residual clutch vibration, and protects the rotor bearings of the generator 4.

[0048] Furthermore, generator 4 is an excitation-type DC generator with a built-in independent excitation coil. The signal line of the excitation coil is electrically connected to the flight control computer. The flight control computer collects the rotor speed signal and outputs a switching signal according to a preset speed threshold to control the excitation circuit to be turned on or off, switching the no-load or loaded power generation state of generator 4. Generator 4 is a separately excited DC generator / shunt-wound DC generator, which requires an independent excitation power supply; for example, the output voltage of the separately excited DC generator / shunt-wound DC generator is 28 volts and the rated current is 100 amperes.

[0049] The flight control computer collects rotor speed signals in real time. When the rotor speed is below the excitation activation speed threshold, the flight control computer outputs a disconnect signal, the excitation circuit is cut off, there is no magnetic field inside generator 4, the rotor idles without generating electrical energy, and there is no reverse drag torque. When the rotor speed increases to above the excitation activation speed threshold, the flight control computer outputs a conduction signal, the excitation circuit is activated, generator 4 establishes a stable magnetic field, and continuously outputs DC power to supply airborne equipment. The excitation activation speed threshold is configured to be higher than the clutch engagement speed threshold, so that the system follows the startup sequence of mechanical engagement driving the rotor first, followed by electrical loading and power supply, avoiding the engine bearing a double load at low speeds. When the excitation disconnect speed threshold is lower than the clutch disengagement speed threshold, mechanical disengagement and electrical no-load are triggered synchronously.

[0050] The working principle of the present invention under all working conditions will be described in detail below.

[0051] During ground start-up, the engine speed gradually increases after ignition. Before reaching the clutch engagement speed threshold of 1800 rpm, clutch block 2161 remains disengaged, and the main rotor experiences no mechanical load. The flight control computer continuously monitors the rotor speed, detecting when it falls below the excitation activation speed threshold of 350 rpm, and automatically cuts off power to the excitation coil, leaving generator 4 completely unloaded with no reverse drag torque. The rubber torsional vibration damper 3 buffers the ignition start-up impact of engine 6 and compensates for minor coaxial misalignment between the engine 6 output shaft and the clutch system 2 input. Engine 6 achieves mechanical and electrical dual no-load start-up, significantly reducing starting resistance.

[0052] During normal flight operations, when the engine speed of 6 rises to over 1800 rpm, the clutch block 2161 expands outward under centrifugal force, the clutch engages, and the torque drives the main rotor to rotate continuously via belt 24. When the rotor speed rises to the excitation activation speed threshold of 350 rpm, the flight control computer activates the excitation circuit, and generator 4 establishes a stable magnetic field to output 28 volts DC power, supplying power to the airborne flight control, navigation, and telemetry equipment. Throughout the flight, the rubber torsional vibration damper 3 continuously attenuates the torsional vibration of engine 6, eliminating the risk of belt 24 slippage and generator 4 eccentric wear.

[0053] In the emergency situation of abnormal engine shutdown in the air, after engine 6 shuts down, its speed drops rapidly to below 1800 rpm. Clutch block 2161 immediately disengages under the action of helical spring 2162, cutting off the mechanical load on the main rotor. The flight control computer detects the rapid drop in rotor speed and instantaneously disconnects the excitation current of generator 4, leaving the generator 4 rotor unloaded and eliminating the reverse torque dragging engine 6. The rubber torsional damper 3 buffers the instantaneous impact of engine shutdown. At this time, because the clutch has cut off the mechanical load and the excitation circuit has cut off the electrical load, engine 6 is in a completely unloaded state without any reverse resistance and can be restarted twice under no-load conditions in one go. After the speed recovers to the threshold, the clutch re-engages, the excitation circuit is activated, and power and airborne power supply are restored synchronously.

[0054] During a touchdown landing, after the helicopter touches the ground, the engine speed of engine 6 drops below the clutch engagement speed threshold, the clutch automatically disengages, and engine 6 no longer drives the main rotor. The rotor speed drops below 300 revolutions per minute, the flight control computer cuts off the excitation current, and generator 4 operates under no-load conditions throughout the landing. The rubber torsional vibration damper 3 absorbs the inertial impact and vibration of the landing fuselage, isolates the impact load, and protects precision components such as the clutch and generator 4 bearings.

[0055] In this embodiment, the power and transmission system for the UAV is operated by an external fuel supply to engine 6. After engine 6 starts, the torque is transmitted to clutch system 2 via rubber torsional damper 3. At low speeds, the clutch disengages and the excitation is disconnected, allowing the engine to start under no-load. Once the speed reaches the clutch engagement threshold, the clutch engages to drive the main rotor. As the speed increases further, the excitation is activated, and the generator supplies power to the onboard equipment. In the event of an accidental engine shutdown in mid-air, the clutch immediately disengages and the excitation is instantly cut off, allowing the engine to return to zero under dual loads and restart smoothly. During landing, the clutch automatically disengages and the excitation is disconnected to prevent wear from a load-bearing shutdown. The rubber torsional damper 3 continuously dampens vibrations and compensates for coaxial misalignment under all operating conditions.

[0056] This embodiment absorbs and attenuates engine torsional vibration and start-stop impact through the rubber torsional vibration damper 3, reducing belt slippage 24 and eccentric wear of generator 4, thus extending the service life of the power system. The coaxial compensation capability of the rubber torsional vibration damper 3 relaxes the assembly alignment accuracy requirements and shortens assembly time. The coaxial linear arrangement and absence of redundant components in the structural design achieves lightweight and compact design. Most importantly, the damper enables a causal chain of reliable clutch disengagement under vibration, clutch disengagement achieving zero mechanical load, and excitation cutoff achieving zero electrical load, thus achieving the technical effect of simultaneous zeroing of dual loads after in-flight engine shutdown and zero-resistance secondary engine restart.

[0057] Example 2 Another specific embodiment of the present invention provides a low-altitude aircraft, including the power and transmission system for an unmanned aerial vehicle described in Embodiment 1. The system is installed in the power compartment of the low-altitude aircraft, and the rubber torsional vibration damper 3, the clutch system 2, and the generator 4 are arranged coaxially along the power flow axis. By employing the aforementioned power and transmission system, the low-altitude aircraft achieves integrated control of power transmission and onboard power supply, improving the success rate of restarting after an in-flight engine failure and enhancing flight safety.

[0058] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A power and transmission system for an unmanned aerial vehicle (UAV), characterized in that, It includes an engine (6), a rubber torsional damper (3), a clutch system (2), a gearbox (5), a laminated flexible coupling (1), and a generator (4); the generator (4) is configured as an excitation-type DC generator; The power output main shaft of the engine (6) is fixedly connected to the input end of the rubber torsional vibration damper (3), and the output end of the rubber torsional vibration damper (3) is fixedly connected to the input end of the clutch system (2). The clutch system (2) transmits power to the gearbox (5) via a belt (24), and the clutch system (2) transmits power to the generator (4) via the laminated flexible coupling (1). The engine (6), the rubber torsional damper (3), the clutch system (2), and the generator (4) are arranged coaxially.

2. The power and transmission system for an unmanned aerial vehicle according to claim 1, characterized in that, The rubber torsional vibration damper (3) includes an output shaft sleeve (31), a rubber-metal composite (32), a torsional vibration damping adapter plate (33), a radial bolt (34), an axial bolt (35), and a positioning pin (36). The positioning pin (36) includes an axial positioning pin and a radial positioning pin. The rubber-metal composite (32) is connected to the torsional vibration damping adapter plate (33) through the axial positioning pin, connected to the output shaft sleeve (31) through the radial positioning pin, connected to the torsional vibration damping adapter plate (33) through the radial bolt (34), and connected to the output shaft sleeve (31) through the axial bolt (35).

3. The power and transmission system for an unmanned aerial vehicle according to claim 2, characterized in that, The rubber torsional damper (3) provides coaxial compensation adjustment in both radial and angular directions, with an adjustment range of 0.3 mm. 1.0mm.

4. The power and transmission system for an unmanned aerial vehicle according to claim 1, characterized in that, The clutch system (2) includes a clutch assembly (21), a clutch left side bracket (22), an arch beam bracket (23), a clutch right side bracket (25), and an I-beam plate (26). The clutch system (2) is fixed to the frame (7) by the arch beam bracket (23); The left clutch bracket (22) and the right clutch bracket (25) are respectively disposed on both sides of the clutch assembly (21), the arch beam bracket (23) is disposed below the clutch assembly (21), and the I-beam plate (26) is connected between the left clutch bracket (22) and the right clutch bracket (25).

5. The power and transmission system for an unmanned aerial vehicle according to claim 4, characterized in that, The clutch assembly (21) includes a clutch housing (211), a clutch pulley (213), a clutch inner shaft (215), a clutch block assembly (216), and a clutch end cap (214). One end of the inner shaft (215) of the clutch is fixedly connected to the output end of the rubber torsional damper (3), and the other end is connected to the generator (4) through the laminated flexible coupling (1); The clutch block assembly (216) is disposed on the outer periphery of the clutch inner shaft (215), the clutch outer cover (211) is sleeved on the outside of the clutch block assembly (216) and fixedly connected to the clutch pulley (213), and the clutch end cover (214) is disposed at the end of the clutch outer cover (211).

6. The power and transmission system for an unmanned aerial vehicle according to claim 5, characterized in that, The clutch assembly (21) also includes a deep groove ball bearing (212) and a needle roller bearing (217). The clutch inner shaft (215) is supported in the inner hole of the clutch pulley (213) by the needle roller bearing (217), and the deep groove ball bearing (212) is disposed between the clutch outer cover (211) and the clutch inner shaft (215).

7. The power and transmission system for an unmanned aerial vehicle according to claim 5, characterized in that, The clutch block assembly (216) includes a clutch block (2161) and a coil spring (2162). The clutch block (2161) is thrown outward by the centrifugal force, overcoming the tension of the helical spring (2162), and engages with the inner wall of the clutch cover (211).

8. The power and transmission system for an unmanned aerial vehicle according to claim 1, characterized in that, The laminated flexible coupling (1) includes a generator mounting plate (11), a diaphragm (12), a transfer plate (13), an intermediate shaft (15), and a clutch mounting plate (17). The generator mounting plate (11) is fixedly connected to the input shaft end of the generator (4), and the clutch mounting plate (17) is fixedly connected to the clutch inner shaft (215) of the clutch system (2).

9. The power and transmission system for an unmanned aerial vehicle according to claim 2, characterized in that, The rubber-metal composite (32) is integrally formed by vulcanization process of fluororubber elastomer and aerospace aluminum alloy inner and outer rings.

10. A low-altitude aircraft, characterized in that, Includes the power and transmission system for an unmanned aerial vehicle as described in any one of claims 1 to 9.

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