An unmanned aerial vehicle power system

Abstract

The unmanned aerial vehicle power system drives external air to enter from the air inlet channel between the hub fairing and the external fairing from top to bottom by the rotation of the propeller, and then flows downward through the inner flow channel and the outer flow channel to cool the motor. The bottom of the hub fairing is inclined outward to guide the airflow to flow along the inner wall of the external fairing, and the external fairing is provided with a bending part inside, so that the sand in the airflow tends to flow outward along the centrifugal direction, thereby making the sand farther away from the inner flow channel, so that the sand cannot enter the inner flow channel and moves downward along the outer flow channel. The first cooling fan rotates with the rotating shaft to ensure that a certain amount of air flows from the outer flow channel into the inner flow channel to cool the motor. The unmanned aerial vehicle power system solves the problem of poor motor cooling effect in the prior art, thereby affecting the working state.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of electric machines, in particular to a power system of a UAV. BACKGROUND

[0002] The motor body in the existing brushless motor mainly includes a stator and a rotor, wherein the rotor of the brushless motor can be arranged as an outer rotor or an inner rotor, the outer rotor brushless motor has large torque, high speed, low power consumption and small noise. Therefore, the electric unmanned aerial vehicle usually uses the outer rotor brushless motor as part of the power system of the unmanned aerial vehicle.

[0003] In the process of working, the brushless motor needs to be effectively cooled to ensure that the brushless motor is in a good working state. In the prior art, the cooling method of the brushless motor of the unmanned aerial vehicle mainly includes that a centrifugal fan is arranged on the top of the rotor of the brushless motor, an air inlet is arranged at the bottom of the brushless motor, a flow channel is formed in the motor, and the airflow can flow through the core and the coil (heat source) on the core, so as to realize the cooling of the motor.

[0004] However, only one centrifugal fan is used for cooling, the airflow speed in the flow channel is low, and the cooling effect is poor. Therefore, in the prior art, the air inlet is arranged upward, the airflow is driven downward by the rotation of the propeller at the top of the unmanned aerial vehicle, the centrifugal fan is assisted, the airflow in the flow channel is accelerated, and the cooling effect is enhanced. However, the propeller can drive sand together with the airflow to enter the motor, which can damage the inside of the motor. Although a screen is arranged at the air inlet to filter the sand, the sand is blocked on the screen, and the screen itself can hinder the airflow, which can affect the cooling effect of the motor and the working state. SUMMARY

[0005] Therefore, the present application aims to provide a power system of a UAV, which can solve the problem that there is no dustproof and good cooling effect power system of a UAV in the prior art.

[0006] The power system of the UAV provided by the present application comprises a rotating shaft, a stator assembly arranged on the rotating shaft, a rotor assembly arranged on the outer side of the stator assembly and connected with the rotating shaft, a fairing assembly arranged on the rotating shaft, and a propeller connected with one end of the rotating shaft.

[0007] The stator assembly comprises a support frame sleeved on the rotating shaft, a coil core component sleeved on the rotating shaft and connected with the bottom of the support frame, the support frame is provided with a through hole, and the coil core component is provided with a through slot matched with the through hole; the rotor assembly comprises a first heat dissipation fan and a second heat dissipation fan connected with the rotating shaft, a steel ring sleeved on the outer side of the coil core component and connected with the side of the second heat dissipation fan, and a permanent magnet component located between the steel ring and the coil core component and connected with the steel ring, the first heat dissipation fan is located in the through hole, and the second heat dissipation fan is located below the stator assembly; the fairing assembly comprises an outer fairing sleeved on the outer side of the steel ring and a hub fairing provided above the support frame and connected with the rotating shaft, the propeller root is located in the hub fairing, the side of the hub fairing is provided with an avoiding slot for avoiding the propeller, the outer fairing is sleeved on the outer side of the hub fairing and connected with the support frame through a connecting piece, the bottom of the hub fairing is outwardly inclined, the outer fairing comprises a bending part and a conformal part provided on both sides of the bending part, the bending part is located at the gap between the hub fairing and the support frame, and a plurality of conformal parts are respectively arranged on the outer sides of the hub fairing, the stator assembly and the rotor assembly, the bending part is concave from inside to outside, and both ends are respectively connected with the conformal parts through transitions; the hub fairing and the outer fairing form an air inlet duct, the hub fairing, the support frame and the coil core component form an internal flow duct, and the outer fairing, the support frame and the steel ring form an external flow duct, wherein, in use, air flow flows into the bending part from the air inlet duct, part of the air flow carrying sand and gravel flows out along the external flow duct, and another part of the air flow not carrying sand and gravel flows out along the internal flow duct.

[0008] The aforementioned UAV power system uses a rotating propeller to draw in outside air from the top down through the air intake duct between the rotor hub fairing and the outer fairing. The air then flows downwards through the inner and outer air ducts to cool the motor. The rotor hub fairing's bottom is tilted outwards, guiding the airflow along the inner wall of the outer fairing. A bend in the outer fairing causes sand and gravel within the airflow to move centrifugally outwards, further away from the inner air duct and preventing it from entering. Furthermore, the outward tilt of the rotor hub fairing causes airflow from the outer duct to the inner duct, requiring upward movement, further hindering sand and gravel from entering the inner duct. Additionally, a first cooling fan, rotating with the shaft, is located within the inner air duct to ensure a certain amount of air flows from the outer duct into the inner air duct to cool the motor. Sand and gravel, due to their greater weight and potential energy than air, are not drawn into the first cooling fan. Furthermore, through internal and external airflow ducts, cool outside air comes into contact with the inner wall of the coil core and the outer wall of the steel ring, cooling the steel ring and core. The coil is wound around the core, and the permanent magnet component is in contact with the inner wall of the steel ring. Since both iron and steel are good conductors of heat, cooling the steel ring and core effectively cools the main components of the motor, including the coil and permanent magnet components. Targeted cooling of the motor's components optimizes heat dissipation, and the airflow driven by the propeller ensures sufficient outside airflow, further improving heat dissipation efficiency. Therefore, this invention solves the problem of the lack of a dustproof and effectively heat-dissipating UAV power system in the prior art.

[0009] In addition, the UAV power system proposed according to the present invention may also have the following additional technical features:

[0010] Preferably, the bottom outer side of the propeller hub fairing is provided with pre-swirl blades, which are located inside the air intake duct.

[0011] Preferably, the support frame is arranged to follow the shape of the propeller hub fairing at one end, so that the connection between the inner flow duct and the air intake duct is inclined from bottom to top.

[0012] Preferably, the rotor hub fairing has an arc-shaped recess at one end near the support frame, and the arc-shaped recess is transitionally connected to the bottom outer side of the rotor hub fairing. The arc-shaped recess is used to guide the airflow direction.

[0013] Preferably, the airfoil angle of the first cooling fan is 5°-40°, the airfoil length of the first cooling fan is 0.05-0.3 times the diameter of the external airflow duct, the airfoil angle of the axial fan blade is 5°-50°, and the airfoil length of the axial fan blade is 0.1-0.35 times the diameter of the external airflow duct.

[0014] Preferably, the outer side of the steel ring is provided with axial flow fan blades, which are located in the outer flow air duct.

[0015] Preferably, the inner wall of the through hole extends towards the center of the through hole with a stator blade, which is located below the first heat dissipation fan.

[0016] Preferably, the unmanned aerial vehicle power system further comprises a control assembly, which comprises a control circuit board arranged on the top of the support frame, and a cooling fin arranged on the control circuit board, and the control circuit board is provided with a groove matched with the through hole.

[0017] Preferably, the hub fairing comprises a top fairing part and a bottom fairing part, and the avoidance groove is arranged on the top fairing part and the bottom fairing part, respectively.

[0018] Preferably, the outer side of the outer fairing is provided with a mounting hole for connecting with a fixed object, so that the outer fairing and the stator assembly are sleeved outside the rotating shaft and do not rotate with the rotating shaft.

[0019] In addition, the present application also provides an unmanned aerial vehicle power device comprising the unmanned aerial vehicle power system. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 The structure diagram of the unmanned aerial vehicle power system provided in an embodiment of the present application is shown;

[0021] Figure 2 The exploded view of Figure 1 ;

[0022] Figure 3 The exploded view of the stator assembly provided in an embodiment of the present application is shown;

[0023] Figure 4 The exploded view of the rotor assembly provided in an embodiment of the present application is shown;

[0024] Figure 5 The cross-sectional view of the unmanned aerial vehicle power system provided in an embodiment of the present application is shown.

[0025] Explanation of main element symbols:

[0026] rotating shaft 10 stator assembly 20 rotor assembly 30 cowl assembly 40 propeller 50 support frame 21 coil core component 22 through hole 211 through slot 221 first cooling fan 31 second cooling fan 32 steel ring 33 permanent magnet component 34 outer cowl 41 hub cowl 42 avoidance slot 43 connecting piece 44 bent portion 411 contour portion 412 air inlet duct 60 inward flow duct 70 outward flow duct 80 pre-rotation blade 45 arc-shaped inward recess 421 axial fan blade 35 stator blade 23 control assembly 90 control circuit board 91 circuit cooling fin 92 groove 93 core cooling fin 24 mounting hole 413

[0027] The following specific embodiments will further illustrate the present application in combination with the above drawings. DETAILED DESCRIPTION

[0028] To facilitate understanding of the present invention, a more complete description will be given below with reference to the accompanying drawings. Several embodiments of the invention are illustrated in the drawings. However, the invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.

[0029] It should be noted that when a component is said to be "fixed to" another component, it can be directly on the other component or there may be an intervening component. When a component is said to be "connected to" another component, it can be directly connected to the other component or there may be an intervening component. The terms "vertical," "horizontal," "left," "right," and similar expressions used in this document are for illustrative purposes only.

[0030] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0031] Please see Figures 1-5 The image shows a UAV power system according to an embodiment of the present invention, including a rotating shaft 10, a stator assembly 20 sleeved on the rotating shaft 10, a rotor assembly 30 sleeved on the outside of the stator assembly 20 and connected to the rotating shaft 10, a fairing assembly 40 disposed on the rotating shaft 10, and a propeller 50 connected to one end of the rotating shaft 10, wherein:

[0032] The stator assembly 20 comprises a support frame 21 sleeved on the rotating shaft 10, a coil core component 22 sleeved on the rotating shaft 10 and connected with the bottom of the support frame 21, the support frame 21 is provided with a through hole 211, and the coil core component 22 is provided with a through slot 221 matched with the through hole 211; the rotor assembly 30 comprises a first heat dissipation fan 31 and a second heat dissipation fan 32 connected with the rotating shaft 10, a steel ring 33 connected with the second heat dissipation fan 32 and sleeved outside the coil core component 22, a permanent magnet component 34 located between the steel ring 33 and the coil core component 22 and connected with the steel ring 33, the first heat dissipation fan 31 is located in the through hole 211, and the second heat dissipation fan 32 is located below the stator assembly 20; the fairing assembly 40 comprises an outer fairing 41 sleeved outside the steel ring 33 and a hub fairing 42 connected with the rotating shaft 10 and arranged above the support frame 21, the root of the propeller 50 is located in the hub fairing 42, the side of the hub fairing 42 is provided with an avoiding slot for avoiding the propeller 50, the outer fairing 41 is sleeved outside the hub fairing 42 and connected with the support frame 21 through a connecting piece 44, the bottom of the hub fairing 42 is inclined outward, the outer fairing 41 comprises a bending part 411 and a conformal part 412 arranged on both sides of the bending part 411, the bending part 411 is located at the gap between the hub fairing 42 and the support frame 21, and a plurality of conformal parts 412 are arranged conformally outside the hub fairing 42, the stator assembly 20 and the rotor assembly 30 respectively, the bending part 411 is concave from inside to outside and connected with the conformal parts 412 at both ends; the hub fairing 42 and the outer fairing 41 form an air inlet duct 60, the hub fairing 42, the support frame 21 and the coil core component 22 form an inner flow duct 70, and the outer fairing 41, the support frame 21 and the steel ring 33 form an outer flow duct 80, wherein, in use, air flows into the bending part from the air inlet duct 60, part of the air flow carrying sand flows out along the outer flow duct 80, and another part of the air flow not carrying sand flows out along the inner flow duct 70.

[0033] It can be understood that by rotating the propeller 50, the external air is brought into the air inlet channel 60 between the hub fairing 42 and the outer fairing 41 from top to bottom, and then flows downward through the inner flow channel 70 and the outer flow channel 80 to cool the motor. Among them, the bottom of the hub fairing 42 is inclined outward to guide the airflow to flow along the inner wall of the outer fairing 41, and the outer fairing 41 is provided with a bending part 411, so that the sand in the airflow tends to flow outward and farther away from the inner flow channel 70, so that the sand cannot enter the inner flow channel 70 and moves downward along the outer flow channel 80. In addition, due to the inclination of the bottom of the hub fairing 42, the airflow from the outer flow channel 80 into the inner flow channel 70 needs to move from bottom to top, which further makes it difficult for sand to enter the inner flow channel 70. In addition, the first cooling fan 31 rotating with the shaft 10 is arranged in the inner flow channel 70 to ensure that a certain amount of air flows from the outer flow channel 80 into the inner flow channel 70 to cool the motor, and the sand cannot be sucked into the first cooling fan 31 due to its own weight and potential energy greater than that of air. In addition, through the inner flow channel 70 and the outer flow channel 80, the external cold air contacts the inner wall of the coil core part 22 and the outer wall of the steel ring 33 to cool the steel ring 33 and the core. The coil is wound on the core, the permanent magnet part 34 contacts the inner wall of the steel ring 33, and both iron and steel are good conductors of heat, so cooling the steel ring 33 and the core cools the main components of the motor, the coil and the permanent magnet part 34. The cooling effect of the motor is optimized, and the airflow driven by the rotation of the propeller 50 ensures the flow speed of the external air and improves the cooling efficiency. Therefore, the present application solves the problem of lack of a dustproof and good cooling effect unmanned aerial vehicle power system in the prior art.

[0034] It should be noted that the second cooling fan 32 is arranged below the stator assembly 20, and the second cooling fan 32 is connected with the shaft 10 and connected with the steel ring 33 on the outer side, so that the shaft 10 drives the second cooling fan 32 and the steel ring 33 to rotate when rotating. In addition, the second cooling fan 32 is located in the inner flow channel 70, and the blade angle of the second cooling fan 32 is greater than that of the first cooling fan 31. Through the rotation of the second cooling fan 32, a negative pressure area is generated below the inner flow channel 70, so that the airflow in the inner flow channel 70 is quickly sucked away, thereby enhancing the cooling effect.

[0035] By setting the pre-swirl vane 45 to rotate with the propeller 50, the airflow in the air inlet duct 60 is further accelerated, and the sand and gravel in the airflow are also accelerated to have greater kinetic energy. Due to the greater kinetic energy, the sand and gravel move downward along the outflow duct 80 and cannot move upward from the outflow duct 80 to the inflow duct 70 against the kinetic energy trend, thereby further improving the dustproof effect inside the motor. In addition, the flow rate in the air inlet duct 60 is increased, that is, the flow rate per unit time is increased, and the airflow flow rate is increased, thereby increasing the airflow flow rates in the inflow duct 70 and the outflow duct 80, and further improving the heat dissipation efficiency.

[0036] In addition, the support frame 21 is conformally arranged on one end side of the boss fairing 42 close to the boss fairing 42, so that the connection between the inflow duct 70 and the air inlet duct 60 is arranged to be inclined from bottom to top. In this way, the gas entering the inflow duct 70 from the outflow duct 80 must move from bottom to top, which increases the difficulty of sand and gravel entering the inflow duct 70 along with the airflow, and increases the dustproof effect.

[0037] Specifically, the boss fairing 42 close to one end of the support frame 21 is provided with an arc-shaped recessed portion 421, which is transitionally connected to the outer bottom of the boss fairing 42. The arc-shaped recessed portion 421 is used to guide the flow direction of the airflow. By setting the arc-shaped recessed portion 421, the airflow flowing into the inflow duct from bottom to top is smoothly transitioned to be deflected, so as to flow downward into the inflow duct 70, thereby making the gas flow orderly and not impacting the inner wall of the boss fairing 42 to generate turbulence, affecting the gas flow speed, and reducing the heat dissipation efficiency.

[0038] In addition, the blade airfoil angle of the first heat dissipation fan 31 is 5°-40°, the blade airfoil length of the first heat dissipation fan 31 is 0.05-0.3 of the diameter of the outflow duct 80, the blade airfoil angle of the axial flow blade 35 is 5°-50°, and the blade airfoil length of the axial flow blade 35 is 0.1-0.35 of the diameter of the outflow duct 80. Since the larger the angle of attack of the blade airfoil and the greater the airfoil length, the greater the flow rate. When the air inlet flow rate in the air inlet duct 60 is constant, the flow rates of the inflow duct 70 and the outflow duct 80 can be adjusted by adjusting the blade airfoil angle and the airfoil length of the first heat dissipation fan 31 and the axial flow blade 35, so that the flow rates in the inflow duct 70 and the outflow duct 80 can be designed according to the requirements, and the heat dissipation effect is maximized.

[0039] Specifically, the outer side of the steel ring 33 is provided with an axial fan blade 35, and the axial fan blade 35 is located in the outer flow air duct 80. When the rotating shaft 10 rotates, the second cooling fan 32, the steel ring 33 and the axial fan blade 35 are driven to rotate. The axial fan blade 35 is located in the inner flow air duct 70, and the rotation of the axial fan blade 35 causes a stronger negative pressure at the bottom of the outer flow air duct 80, so that the airflow in the outer flow air duct 70 is discharged faster, thereby enhancing the cooling effect.

[0040] Further, the inner wall of the through hole 211 extends towards the center of the through hole 211 and has a stator blade 23, and the stator blade 23 is located below the first cooling fan 31. When the external cold air is sucked into the motor through the first cooling fan 31 and enters the inner flow air duct 70, the wake will rotate and affect the gas flow direction, which is not conducive to the rapid flow of cold air in the inner flow air duct 70. Therefore, the static stator blade 23 is arranged to straighten the rotating airflow, so that the gas flow direction is determined to flow along the inner flow air duct 70, thereby improving the cooling effect.

[0041] In addition, the unmanned aerial vehicle power system further includes a control assembly 90, which includes a control circuit board 92 arranged on the top of the support frame 21, and a circuit heat sink 92 arranged on the control circuit board 91, and a groove 93 adapted to the through hole 211 is formed on the control circuit board 91. The control assembly 90 is used for receiving external signals to control the motor. The control assembly 90 is arranged on the top of the support frame 21, so that the external gas enters the motor to be divided before being cooled by the circuit heat sink 92 to cool the control assembly 90. Because the heat resistance of the control assembly 90 is relatively poor, such arrangement ensures that this place is preferably cooled, and the control assembly 90 is not affected by the high-temperature airflow after the heat dissipation of other heat sources.

[0042] Specifically, the coil core component 22 extends outwardly and has a core heat sink 24, and the core heat sink 24 is located in the through slot 221. By additionally extending the core heat sink 24, the core heat sink 24 is located in the inner flow air duct 70, thereby increasing the heat dissipation area of the coil core component 22, thereby improving the cooling effect.

[0043] In addition, the outer side of the external fairing 41 is provided with a mounting hole 413 for connecting with a fixed object, so that the external fairing 41 and the stator assembly 20 are sleeved on the outer side of the rotating shaft 10 and do not rotate with the rotating shaft 10. The coil core 22 is fixed on the support frame 21, the support frame 21 is connected with the external fairing 41 through the connecting piece 44, and the external fairing 41 is connected with the fixed object through the mounting hole 413 on the outer side, so that the stator assembly 20 and the external fairing 41 are sleeved on the rotating shaft 10, but do not rotate with the rotating shaft 10.

[0044] In summary, the unmanned aerial vehicle power system in the above embodiments of the present application, by the rotation of the propeller 50, drives the outside air from the air inlet duct 60 between the hub fairing 42 and the outer fairing 41 from top to bottom, and then flows downward through the inner flow duct 70 and the outer flow duct 80 to cool the motor. Among them, the bottom of the hub fairing 42 is inclined outward, guiding the airflow to flow along the inner wall of the outer fairing 41, and the outer fairing 41 is provided with a bending part 411, so that the sand in the airflow tends to flow outward due to centrifugal force, thereby making the sand farther away from the inner flow duct 70, so that the sand cannot enter the inner flow duct 70, and moves downward along the outer flow duct 80. In addition, since the bottom of the hub fairing 42 is inclined outward, the airflow from the outer flow duct 80 into the inner flow duct 70 needs to move from bottom to top, which further makes it difficult for sand to enter the inner flow duct 70. In addition, the first cooling fan 31 rotating with the shaft 10 is arranged in the inner flow duct 70 to ensure that a certain amount of air flows from the outer flow duct 80 into the inner flow duct 70 to cool the motor, and the sand cannot be sucked into the first cooling fan 31 due to its own weight and potential energy greater than that of air. In addition, through the inner flow duct 70 and the outer flow duct 80, the outside cold air contacts the inner wall of the coil core part 22 and the outer wall of the steel ring 33 to cool the steel ring 33 and the core. The coil is wound on the core, the permanent magnet part 34 contacts the inner wall of the steel ring 33, and both iron and steel are good conductors of heat. Cooling the steel ring 33 and the core cools the main components of the motor, the coil and the permanent magnet part 34. The cooling of the components in the motor is targeted to achieve the best cooling effect, and the airflow driven by the rotation of the propeller 50 ensures the flow speed of the outside air and improves the cooling efficiency. Therefore, the present application solves the problem of lack of a dustproof and good cooling unmanned aerial vehicle power system in the prior art.

[0045] In the description of the present specification, the description of the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" and the like means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In the present specification, the illustrative description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0046] The above embodiments only express several implementation manners of the present application, and the description is more specific and detailed, but it should not be understood as a limitation on the patent scope of the present application. It should be noted that for ordinary skilled persons in the art, without departing from the concept of the present application, several modifications and improvements can be made, which are within the protection scope of the present application. Therefore, the protection scope of the patent of the present application should be subject to the appended claims.

Claims

1. A power system for an unmanned aerial vehicle (UAV), characterized in that, It includes a rotating shaft, a stator assembly sleeved on the rotating shaft, a rotor assembly sleeved on the outside of the stator assembly and connected to the rotating shaft, a fairing assembly disposed on the rotating shaft, and a propeller connected to one end of the rotating shaft; The stator assembly includes a support frame sleeved on the rotating shaft and a coil core component sleeved on the rotating shaft and connected to the bottom of the support frame. The support frame has a through hole, and the coil core component has a through slot adapted to the through hole. The rotor assembly includes a first cooling fan and a second cooling fan connected to the rotating shaft, a steel ring sleeved on the outside of the coil core component and connected to the side of the second cooling fan, and a permanent magnet component located between the steel ring and the coil core component and connected to the steel ring. The first cooling fan is located inside the through hole, and the second cooling fan is located below the stator assembly. The fairing assembly includes an outer fairing fitted around the outside of the steel ring and a hub fairing disposed above the support frame and connected to the rotating shaft. The root of the propeller is located inside the hub fairing. The side of the hub fairing is provided with a clearance groove for avoiding the propeller. The outer fairing is fitted around the outside of the hub fairing and connected to the support frame through a connector. The bottom of the hub fairing is inclined outward. The outer fairing includes a bent portion and conforming portions disposed on both sides of the bent portion. The bent portion is located in the gap between the hub fairing and the support frame. A plurality of conforming portions are respectively conformally disposed to the outside of the hub fairing, the stator assembly, and the rotor assembly. The bent portion is concave from the inside to the outside and its two ends are respectively transitionally connected to the conforming portions. The hub fairing and the outer fairing together form an air intake duct, the hub fairing, the support frame and the coil core component together form an inner airflow duct, and the outer fairing, the support frame and the steel ring together form an outer airflow duct. The outer side of the steel ring is provided with axial flow fan blades, which are located inside the external airflow duct; In use, airflow flows from the air intake duct to the bend, with a portion of the airflow carrying sand and gravel flowing out along the outward airflow duct, and the other portion of the airflow not carrying sand and gravel flowing out along the inward airflow duct.

2. The UAV power system according to claim 1, characterized in that, The bottom outer side of the propeller hub fairing is provided with pre-swirl blades, which are located inside the air intake duct.

3. The UAV power system according to claim 2, characterized in that, The support frame is arranged to follow the shape of the propeller hub fairing at one end, so that the connection between the inner flow duct and the air intake duct is inclined from bottom to top.

4. The UAV power system according to claim 3, characterized in that, The propeller hub fairing has an arc-shaped recess at one end near the support frame. The arc-shaped recess is transitionally connected to the bottom outer side of the propeller hub fairing. The arc-shaped recess is used to guide the airflow direction.

5. The unmanned aerial vehicle (UAV) power system according to claim 1, characterized in that, The first cooling fan has a blade airfoil angle of 5°-40° and a blade airfoil length of 0.05-0.3 times the diameter of the external airflow duct. The axial fan blade has a blade airfoil angle of 5°-50° and a blade airfoil length of 0.1-0.35 times the diameter of the external airflow duct.

6. The UAV power system according to claim 1, characterized in that, Stator blades extend from the inner wall of the through hole toward the center of the through hole, and the stator blades are located below the first cooling fan.

7. The unmanned aerial vehicle (UAV) propulsion system according to any one of claims 1 to 6, characterized in that, The UAV power system also includes a control component, which includes a control circuit board disposed on the top of the support frame and a heat sink disposed on the control circuit board. The control circuit board has a groove adapted to the through hole.

8. The unmanned aerial vehicle power system according to claim 7, characterized in that, The coil core component has a core heat sink extending outward, and the core heat sink is located in the through slot.

9. The unmanned aerial vehicle power system according to claim 8, characterized in that, The outer fairing has mounting holes on its outer side for connection with a fixed object, so that the outer fairing and the stator assembly are fitted onto the outside of the rotating shaft and do not rotate with the rotating shaft.

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