Multi-source coupling driving cross-medium unmanned aerial vehicle power device

Abstract

The invention discloses a multi-source coupling driven cross-medium unmanned aerial vehicle power device, and relates to the technical field of cross-medium aircrafts. The device comprises a machine base assembly, a plurality of driving units distributed in the circumferential direction, input gears connected with the driving units respectively, and a center output gear located in the center and externally meshed with the input gears. Through a multi-path parallel fixed shaft transmission structure without an inner gear ring, the power of a plurality of driving units is converged to a central output shaft. By means of the gear speed reduction and torque increasing principle, the propeller obtains high torque output at the low rotating speed, the problem of non-linear torque surge caused by liquid drop impact at the near-water-surface stage and the water outlet stage of the cross-medium aircraft is effectively solved, and the water-air mixing flow field and the lift force attenuation effect induced by the high rotating speed are avoided by means of the low rotating speed characteristic; and meanwhile, due to the multi-motor redundancy design, the anti-interference capability and the task reliability of the power system under the severe sea condition are remarkably improved.

Description

Technical Field

[0001] This invention belongs to the field of cross-medium aircraft technology, and particularly relates to a multi-source coupled drive cross-medium unmanned aerial vehicle power unit. Background Technology

[0002] Cross-medium unmanned aerial vehicles (UAVs) possess both aerial and underwater capabilities, showing broad application prospects in civilian and scientific research fields such as marine scientific observation, underwater resource exploration, cross-domain communication relay, and emergency rescue. However, air and water have vastly different physical properties; water is approximately 800 times denser than air, and their viscosity differs significantly. When an aircraft performs cross-medium missions, especially during the crossing of the water-air interface, abrupt changes in the fluid medium can lead to nonlinear and drastic fluctuations in hydrodynamic loads. This transient fluid-structure interaction places extremely high demands on the output stability and shock resistance of the propulsion system. Existing cross-medium UAV propulsion systems typically employ a "single-motor direct-drive rotor" architecture. While this architecture is simple, it exhibits significant technical limitations under high-load conditions near the water surface. Relevant aerodynamic studies and experimental data indicate that the aerodynamic characteristics of the rotor operating near the water surface are fundamentally different from those of conventional ground effects, primarily manifested in the following ways: On the one hand, to obtain sufficient thrust above the water, direct-drive systems often need to increase the throttle to increase the rotational speed. However, the strong downwash generated by the high-speed rotor violently impacts the water surface, entraining a large number of water droplets and forming a high-density water-air mixed flow field. The dense droplets impacting the blades at high speed lead to a decrease in the rotor torque coefficient (…). The torque density of traditional direct-drive motors is limited, making it difficult to provide sufficient instantaneous torque redundancy. This makes them prone to stalling or sudden speed drops during water splashes, leading to instability.

[0003] On the other hand, under high-speed, strongly disturbed flow fields, the near-water surface effect no longer provides lift enhancement, but may instead trigger a "negative ground effect" phenomenon, resulting in reduced lift and a lower rotor stall angle of attack.

[0004] In summary, existing direct-drive systems struggle to simultaneously resolve the contradiction between "drastic torque increase due to medium density differences" and "lift reduction due to high-speed aerodynamic interference." Therefore, there is an urgent need to develop a novel cross-medium UAV power unit capable of providing high-load drive capability while maintaining low rotor speed and possessing high torque redundancy. Summary of the Invention

[0005] In view of this, the present invention provides a multi-source coupled drive cross-medium UAV power unit that can provide high load drive capability while maintaining a low rotor speed and has high torque redundancy.

[0006] A multi-source coupled drive trans-medium unmanned aerial vehicle (UAV) power unit, comprising: The base assembly includes a motor mounting bracket; The drive assembly includes multiple drive units fixed to the motor mounting base and distributed circumferentially; The transmission assembly includes input gears connected to the output shaft of each drive unit, and a central output gear located at the center of the area enclosed by the input gears and simultaneously meshing with the multiple input gears, forming a multi-path parallel drive structure; the number of teeth of the input gears is less than the number of teeth of the central output gear, constituting a multi-input single-output speed reduction and torque amplification transmission system; The output shaft system assembly includes a central output shaft that is coaxially fixed to the central output gear; the central output shaft is used to mount the blades.

[0007] Preferably, multiple drive units are fixed to the rear end face of the motor mounting base, and the output shaft of the drive unit passes through the motor mounting base and connects to the input gear; The central output shaft rod enters from the rear end face of the motor mounting base, passes through the central output gear, and connects to the blade; the limiting part at the tail end of the rod abuts against the rear end face of the motor mounting base for axial limiting.

[0008] Preferably, the output shaft assembly further includes a composite support structure consisting of radial support bearings and thrust bearings spaced axially along the central output shaft to withstand bidirectional impacts during the cross-medium process.

[0009] Preferably, the composite support structure includes: a radial support bearing, a thrust bearing, and a front thrust bearing; A radial support bearing, installed inside the motor mounting base, is used to support the central output shaft; A thrust bearing is sleeved on the central output shaft and fixed inside the main bearing housing, which is located between the central output gear and the motor mounting base and is installed on the front end face of the motor mounting base. A front thrust bearing is sleeved on the central output shaft and located between the front end face of the central output gear and the transmedium propeller. The thrust bearing and the front thrust bearing are used to withstand the positive tensile force and the reverse impact force during the cross-medium process, respectively.

[0010] Preferably, the radial support bearing is fixed in a countersunk hole opened on the rear end face of the motor mounting base.

[0011] Preferably, the connection structure between the input gear and the drive unit includes: a transmission locking ring sleeved on the output shaft of the drive unit; a fastening set screw that is radially screwed into the transmission locking ring and abuts against the output shaft of the drive unit; the hub end face of the input gear is provided with a mating notch, and the head of the radial fastening screw is accommodated in the mating notch to form a circumferential transmission limiting structure.

[0012] Preferably, the connection between the center output gear and the center output shaft is as follows: the center output shaft has a transverse pin hole in the middle, and the center hole of the center output gear has a positioning slot; the torque transmission and axial positioning of the center output gear are realized by the positioning pin passing through the transverse pin hole and being embedded in the positioning slot.

[0013] Preferably, it further includes: a front protective cover, which is fixedly connected to the base assembly by a fourth fastener to close the meshing area of ​​the input gear and the center output gear; the inner side of the front protective cover abuts against the upper ring of the front thrust bearing to apply axial preload.

[0014] Preferably, the device is connected to the cross-medium UAV via multiple body connecting columns.

[0015] Preferably, the ratio of the number of teeth of the input gear to the number of teeth of the central output gear is 3:5, and the reduction ratio is 1.67.

[0016] Compared with the prior art, the present invention has the following significant advantages: (1) This invention amplifies the output torque through a gear reduction mechanism, utilizing the principle of physical levers. Based on the power balance equation... (in For torque, (where angular velocity is constant) and with the total power remaining constant, the output speed is reduced. This achieves output torque The torque is multiplied. Even under conditions where the drag torque spikes instantaneously due to droplet impact at the water-air interface, this system, thanks to the high torque gain and power redundancy provided by the reduction mechanism, can still provide enough driving torque to overcome nonlinear hydrodynamic resistance, powerfully driving the blades to break through the water, effectively preventing sudden drops in speed or motor stall, and ensuring the continuity and stability of the cross-medium water discharge process.

[0017] (2) Thanks to the increased torque, this device can be matched with large pitch or large-size blades, and can generate sufficient takeoff thrust at a low speed. This "low speed" operation mode significantly reduces the frequency and intensity of the downwash airflow impacting the water surface, reduces water splash and the formation of water-air mixed flow field from the source, avoids lift attenuation caused by droplet interference flow field at high speed, and improves near-water surface hovering and cross-medium stability.

[0018] (3) Multiple drive units are connected in parallel to drive the same output gear. When one of the drive units fails due to a fault, the remaining drive units can still drive the central shaft to rotate through gear meshing, resulting only in a decrease in maximum output power, without causing a complete loss of power. This distributed redundancy design significantly improves the mission reliability and fault tolerance of UAVs in complex marine environments.

[0019] (4) In response to the sudden change of huge axial tensile force across the medium, that is, the sudden change from the hovering tensile force in the air to the huge resistance in the water, the composite support structure of "bidirectional thrust bearing + radial bearing" designed in this invention can effectively absorb the irregular impact from the blade, protect the gear meshing accuracy, and extend the mechanical life. Attached Figure Description

[0020] Figure 1 This is an exploded view of the driving component in an embodiment of the present invention; Figure 2 This is an exploded structural diagram of the main bearing housing assembly in an embodiment of the present invention; Figure 3 This is an exploded assembly diagram of the transmission component in an embodiment of the present invention; Figure 4 This is a cross-sectional view of the output shaft system assembly in an embodiment of the present invention. Figure 5 This is a planar projection schematic diagram of the multi-gear meshing transmission in an embodiment of the present invention; Figure 6 This is a three-dimensional assembly diagram of the propeller and powertrain in an embodiment of the present invention; Figure 7 This is a schematic diagram of the installation structure of the protective cover in an embodiment of the present invention; Figure 8 This is a top view schematic diagram of the overall structure of the cross-media UAV in an embodiment of the present invention.

[0021] In the diagram: 100 - Multi-source coupled drive power unit for cross-medium UAV; 200 - Cross-medium UAV; 101 - Drive unit; 102 - Motor mounting base; 103 - First fastener; 104 - Main bearing housing; 105 - Thrust bearing; 106 - Second fastener; 107 - Transmission locking ring; 108 - Fastening set screw; 109 - Body connecting column; 110 - Third fastener; 111 - Radial support bearing; 112 - Center output shaft; 113 - Positioning pin; 114 - Input gear; 115 - Center output gear; 116 - Front thrust bearing; 117 - Propeller blade; 118 - Front protective cover; 119 - Fourth fastener. Detailed Implementation

[0022] This invention provides a multi-source coupled drive cross-medium unmanned aerial vehicle (UAV) power unit to address the following problems of existing solutions: (1) The contradiction between insufficient torque reserve and sudden change in nonlinear resistance: Existing single-motor direct drive systems are unable to cope with the torque coefficient caused by the density difference of the medium and the impact of droplets when crossing the medium. A sharp increase in nonlinearity can easily lead to motor stall or a sudden drop in speed.

[0023] (2) High-speed-induced flow field interference: In order to obtain large thrust, traditional systems need to increase the speed, but this intensifies the impact of the downwash airflow on the water surface, forming a large number of splashing droplets that interfere with the rotor aerodynamic shape, leading to lift reduction or even stall.

[0024] (3) Single point of failure risk: Traditional single motor systems lack redundancy. Once the motor fails or is jammed by foreign objects in severe sea conditions, the aircraft will directly lose power.

[0025] To address the aforementioned technical problems, this invention proposes a multi-source coupled drive cross-medium UAV power unit. The unit mainly includes a base assembly, multiple drive units circumferentially distributed within the base assembly, input gears connected to each drive unit, and a central output gear located at the center of the area enclosed by the input gears and meshing externally with each input gear. Through a multi-path parallel fixed-axis transmission structure formed by the multiple input gears and the central output gear, the power of the multiple drive units is converged to the central output shaft. The central output shaft is used to drive the propeller blades to rotate. As a core improvement of this invention, the number of teeth on the input gears... Less than the number of teeth of the central output gear The system forms a multi-input, single-output, reduction-and-torque-increasing fixed-shaft transmission system with a transmission ratio of... .

[0026] As can be seen, this invention utilizes the principle of gear reduction and torque amplification to enable the propeller blades to obtain high torque output at low speeds, effectively solving the problem of nonlinear torque surge caused by droplet impact during the near-water and out-of-water phases of cross-medium aircraft. It also utilizes the low-speed characteristics to avoid the water-air mixing flow field and lift attenuation effect induced by high-speed operation. At the same time, the multi-motor redundancy design significantly improves the anti-interference capability and mission reliability of the power system under harsh sea conditions.

[0027] Furthermore, this invention employs a multi-stage bearing support structure in the device, including a radial support bearing to withstand radial loads, and thrust bearings and a front thrust bearing located before and after the central output gear, respectively, to withstand bidirectional axial impacts during the cross-medium process. This composite structure can effectively absorb irregular impacts from the blades, protect gear meshing accuracy, and extend mechanical life.

[0028] The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings and examples.

[0029] like Figure 1-8 As shown, this embodiment provides a multi-source coupled drive cross-medium UAV power unit 100, which is installed on a cross-medium UAV 200. The unit mainly includes a base assembly, a drive assembly, a transmission assembly, and an output shaft system assembly.

[0030] Base components, such as Figure 1 , Figure 2 and Figure 3 As shown, it mainly includes a motor mounting base 102 and a main bearing housing 104. One side of the motor mounting base 102 is used to mount the transmission assembly and output shaft assembly, referred to as the front end face; the other side of the motor mounting base 102 is used to mount the drive assembly, referred to as the rear end face. The main bearing housing 104 is fixed to the center of the front end face of the motor mounting base 102. In this embodiment, the main bearing housing 104 is securely connected to the front end face of the motor mounting base 102 by a second fastener 106. Furthermore, the body connecting column 109 is also part of this assembly; one end is connected to the frame of the cross-medium UAV 200, and the other end is fixed to the edge of the rear end face of the motor mounting base 102 by a third fastener 110, thereby achieving a stable mechanical connection between the power unit and the body.

[0031] Driver components, such as Figure 1 and Figure 2 As shown, the drive assembly provides the power source for the system. In this embodiment, four drive units 101 are evenly distributed along the circumference of the motor mounting base 102. Each drive unit 101 is fixed to the rear end face of the motor mounting base 102. In this embodiment, the drive unit 101 is securely mounted to the rear end face of the motor mounting base 102 by a first fastener 103 passing through the front end face. A drive unit 101 can be fixed by multiple first fasteners 103. The output axis of the drive unit 101 passes forward through the motor mounting base 102 and extends into the transmission area.

[0032] Transmission components, such as Figure 3 , Figure 4 and Figure 5 As shown, the transmission assembly is responsible for converging and transmitting the power of the four drive units to the center, and is the core of torque transmission. This transmission assembly includes an input gear 114 connected to the output shaft of each drive unit 101, and a central output gear 115 located at the center of the area enclosed by the input gears 114 and simultaneously meshing with multiple input gears 114. By eliminating the internal gear ring in a multi-path parallel fixed-axis transmission structure, the power of multiple drive units is converged to the central output shaft.

[0033] Regarding the connection at the input end (motor side): To prevent the pinion from slipping under high torque, this invention employs a "positive locking" structure. A transmission locking ring 107 is fitted onto the output shaft of each drive unit 101. A fastening set screw 108 passes through a threaded hole on the transmission locking ring 107 and abuts against the motor output shaft. An input gear 114 is fitted onto the outside of the transmission locking ring 107, and the hub of the input gear 114 has a groove that matches the shape of the head of the fastening set screw 108. In this way, the fastening set screw 108 not only achieves axial fixation of the transmission locking ring 107 but also acts as a reliable force transmission limiting structure, reliably transmitting the motor torque to the input gear 114.

[0034] For the connection at the output end (center side): the locating pin 113 passes through the transverse pin hole in the middle of the center output shaft 112. The center output gear 115 is sleeved on the center output shaft 112, and its center hole has a groove that mates with the locating pin 113. When the four input gears 114 are installed in place, they simultaneously engage with the center output gear 115 located in the center, forming a multi-path parallel drive structure.

[0035] Output shaft system components, such as Figure 4 and Figure 6 As shown, the output shaft assembly is used to support rotating components, withstand complex loads during cross-medium processes, and output final power. Figure 4 and Figure 6 As shown, it includes a central output shaft 112, which is coaxially fixed with a central output gear 115 for directly driving the blades 117.

[0036] The output shaft assembly also includes a multi-stage composite support structure: to cope with complex fluid-structure interaction impacts, this multi-stage composite support structure includes radial support bearings and thrust bearings spaced axially along the central output shaft to withstand bidirectional impacts during the cross-medium process. In this embodiment, the thrust bearings are as follows: Figure 2 and Figure 4 As shown in the sectional view, this device adopts a multi-bearing layout of "bidirectional thrust bearing + radial bearing", specifically including thrust bearing 105, radial support bearing 111 and front thrust bearing 116.

[0037] The radial support bearing 111 is installed inside the motor mounting base 102 to support the central output shaft 112, ensuring the rotational accuracy of the central output shaft 112 and bearing radial force. In this embodiment, the radial support bearing 111 is embedded in a groove opened at the center of the rear end face of the motor mounting base 102, which facilitates installation. Its two end faces respectively abut against the limiting part at the end of the central output shaft 112 and the motor mounting base 102; the inner ring and outer ring of the bearing in the motor mounting base 102 respectively contact the central output shaft 112 and the motor mounting base 102.

[0038] The thrust bearing 105 is sleeved on the central output shaft 112 and fixed inside the main bearing housing 104. In this embodiment, the thrust bearing 105 is embedded in a groove opened on the front end face of the main bearing housing 104, and the upper and lower rings of the bearing contact the main bearing housing 104 and the central output gear 115, respectively.

[0039] A front thrust bearing 116 is sleeved on the central output shaft 112 and located between the front end face of the central output gear 115 and the transmedium blade 117. This front thrust bearing 116 is used to withstand reverse axial impact force and, together with the thrust bearing 105, forms bidirectional axial support.

[0040] When the drone hovers in the air, the thrust bearing 105 bears the load due to the forward pulling force; when the drone enters the water or is impacted by the water surface, the resistance moves backward, and the front thrust bearing 116 bears the load. Therefore, the thrust bearing 105 and the front thrust bearing 116 are used to withstand the forward pulling force and the reverse impact force during the cross-medium process, respectively. Together with the intermediate radial support bearing 111, this shaft system can cope with the intense, instantaneous fluid-structure interaction impact across the medium from all directions, protecting the gear meshing clearance from becoming unchanged.

[0041] In this embodiment, the central output shaft 112 includes a limiting part and a shaft part. The shaft part of the central output shaft 112 passes through the radial support bearing 111 in the motor mounting seat 102, the thrust bearing 105 in the main bearing seat 104, the central output gear 115, and the front thrust bearing 116 in sequence, and is limited by the limiting part.

[0042] Closure and protection: such as Figure 7 As shown, the device also includes a closure and protection assembly, comprising a front protective cover 118 and its mounting elements. After the front thrust bearing 116 is installed, the front protective cover 118 is secured to the extension post of the main bearing housing 104 or the motor mounting base 102 by a fourth fastener 119. This front protective cover 118 not only serves to rectify airflow and prevent water and air intrusion, but also abuts against the outside of the front thrust bearing 116, applying axial preload. Finally, the blade 117 is mounted and fixed to the foremost end of the central output shaft 112.

[0043] Regarding the transmission principle and parameter design, let the number of teeth of each input gear 114 be... The number of teeth on the center output gear 115 is In a preferred embodiment of the invention, in order to obtain the ideal torque amplification factor within a limited space, the number of teeth of the input gear 114 is selected. The number of teeth of the center output gear 115 At this point, the system's deceleration ratio... The calculation is as follows: According to the law of conservation of power (in For torque, Angular velocity, (for transmission efficiency), output torque at blade 117 end With the output torque of a single motor The relationship is: This means that, under ideal conditions, this device can output nearly 6.68 times the torque of a single motor.

[0044] The structural design of this embodiment brings the following significant effects: 1. Low-Speed ​​Operation Avoiding Water-Air Mixing Flow: As mentioned in the background technology, rotors at high speeds violently impact the water surface, entraining droplets and creating a disruptive flow field. This invention, through a reduction ratio of 1.67, allows the blade speed to be only approximately 4800 RPM when the motor operates in its high-efficiency range (e.g., 8000 RPM). This reduction drive strategy significantly weakens the shearing effect of the downwash airflow on the water surface, reduces the generation of splashing droplets, and thus maintains good near-water surface lift characteristics.

[0045] 2. High torque resists nonlinear drag abrupt changes: When an aircraft emerges from underwater or flies close to the water surface, the impact of droplets causes a drag torque on the propeller blades ( The torque gain increases nonlinearly. Thanks to the huge torque gain calculated by the above formula, this device can output a driving torque sufficient to overcome the high-intensity hydrodynamic resistance, powerfully driving the blades to break through the water, effectively preventing motor stall or sudden speed drop caused by sudden increase in resistance, and ensuring attitude stability during the cross-medium process.

[0046] 3. Omnidirectional shock-resistant bearing layout: such as Figure 2 and Figure 6 As shown, the thrust bearing 105 and the front thrust bearing 116 are located on the front and rear sides of the central output gear 115, respectively, forming an axial constraint. When the UAV hovers in the air, the pulling force is forward, and the thrust bearing 105 bears the load; when the UAV enters the water or is hit by the water surface, the resistance is backward, and the front thrust bearing 116 bears the load. Together with the intermediate radial support bearing 111, this shaft system can cope with the intense, instantaneous fluid-structure interaction impact across the medium in all directions, protecting the gear meshing clearance from becoming unchanged.

Claims

1. A multi-source coupled drive cross-medium unmanned aerial vehicle (UAV) power unit, characterized in that, include: A base assembly, including a motor mounting bracket (102); The drive assembly includes a plurality of drive units (101) fixed to the motor mounting base (102) and distributed circumferentially. The transmission assembly includes an input gear (114) connected to the output shaft of each drive unit (101) and a central output gear (115) located at the center of the area enclosed by the input gears (114) and simultaneously meshing with the multiple input gears (114), forming a multi-path parallel drive structure; the number of teeth of the input gears (114) is less than the number of teeth of the central output gear (115), constituting a multi-input single-output speed reduction and torque amplification transmission system; The output shaft assembly includes a central output shaft (112) coaxially fixed with the central output gear (115); the central output shaft (112) is used to mount the blades (117).

2. The multi-source coupled drive cross-medium UAV power unit according to claim 1, characterized in that, Multiple drive units (101) are fixed to the rear end face of the motor mounting base (102), and the output shaft of the drive unit (101) passes through the motor mounting base (102) and connects to the input gear (114). The central output shaft (112) rod enters from the rear end face of the motor mounting base (102), passes through the central output gear (115), and connects to the blade (117); the limiting part at the tail end of the rod abuts against the rear end face of the motor mounting base (102) for axial limiting.

3. The multi-source coupled drive cross-medium UAV power unit according to claim 1, characterized in that, The output shaft assembly further includes a composite support structure consisting of radial support bearings and thrust bearings spaced axially along the central output shaft to withstand bidirectional impacts during the cross-medium process.

4. The multi-source coupled drive cross-medium UAV power unit according to claim 3, characterized in that, The composite support structure includes: a radial support bearing (111), a thrust bearing (105), and a front thrust bearing (116). A radial support bearing (111) is installed in the motor mounting base (102) to support the central output shaft (112). The thrust bearing (105) is sleeved on the central output shaft (112) and fixed inside the main bearing housing (104). The main bearing housing (104) is located between the central output gear (115) and the motor mounting base (102) and is installed on the front end face of the motor mounting base (102). A front thrust bearing (116) is sleeved on the central output shaft (112) and located between the front end face of the central output gear (115) and the transmedium propeller (117). The thrust bearing (105) and the front thrust bearing (116) are respectively used to withstand the positive tensile force and the reverse impact force during the cross-medium process.

5. A multi-source coupled drive cross-medium UAV power unit according to claim 4, characterized in that, The radial support bearing (111) is fixed in the countersunk hole opened on the rear end face of the motor mounting base (102).

6. The multi-source coupled drive cross-medium UAV power unit according to claim 1, characterized in that, The connection structure between the input gear (114) and the drive unit (101) includes: a transmission locking ring (107) sleeved on the output shaft of the drive unit (101); a fastening set screw (108) that is radially screwed into the transmission locking ring (107) and abuts against the output shaft of the drive unit (101); the hub end face of the input gear (114) is provided with a mating notch, and the head of the radial fastening screw (108) is accommodated in the mating notch to form a circumferential transmission limiting structure.

7. A multi-source coupled drive cross-medium UAV power unit according to claim 1, characterized in that, The connection between the central output gear (115) and the central output shaft (112) is as follows: the central output shaft (112) has a transverse pin hole in the middle, and the central hole of the central output gear (115) has a positioning slot; the torque transmission and axial positioning of the central output gear (115) are realized by the positioning pin (113) passing through the transverse pin hole and embedding into the positioning slot.

8. A multi-source coupled drive cross-medium UAV power unit according to claim 4, characterized in that, Also includes: The front protective cover (118) is fixedly connected to the base assembly by the fourth fastener (119) to close the meshing area of ​​the input gear (114) and the center output gear (115); the inner side of the front protective cover (118) abuts against the upper ring of the front thrust bearing (116) to apply axial preload.

9. A multi-source coupled drive cross-medium UAV power unit according to claim 1, characterized in that: The device is connected to the cross-medium unmanned aerial vehicle (200) via multiple body connecting posts (109).

10. A multi-source coupled drive cross-medium UAV power unit according to claim 1, characterized in that: The ratio of the number of teeth of the input gear (114) to the number of teeth of the center output gear (115) is 3:5, and the reduction ratio is 1.67.

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