External rotor motor ducted fan system with high integration level and efficient cooling

Abstract

The invention discloses a high-integration-level and efficient-cooling external rotor motor ducted fan system, which belongs to the technical field of ducted fans and comprises a motor stator winding and a fan external rotor integrated part integrally formed by fan blades and a motor external rotor turntable, the integrated shell is integrally formed by a motor inner stator sleeve, a ducted nacelle, a motor controller main shell and a plurality of groups of ducted stationary blades; a cooling structure is mounted on the integrated shell; a motor stator winding is fixedly connected to the outer wall of one end of the integrated shell, the front flow guide cover is fixedly connected to the fan outer rotor integrated part, and the rear flow guide cover is installed at the other end of the integrated shell. And the integrated shell is rotationally connected with the fan outer rotor integrated piece. The system is low in noise, high in integration level, high in system reliability, high in system cooling efficiency, high in power level compatibility and high in expandability.

Description

Technical Field

[0001] The present invention relates to the technical field of ducted fans, and in particular to a highly integrated, highly efficient cooling outer rotor motor ducted fan system. Background Art

[0002] For the electric propulsion systems of electric / hybrid aircraft, conventional aircraft (CTOL), short take-off and landing aircraft (STOL) and vertical take-off and landing aircraft (EVTOL), the electric ducted fan propulsion system is the most preferred electric propulsion system solution in the future electric aviation field due to its high efficiency and energy saving, compact structure and low noise.

[0003] The core components of the electric ducted fan propulsion system include the fan, drive motor, motor controller, duct (nacelle), guide vanes and center body hub. These components work together to accelerate the airflow and generate thrust. Among them, the fan is a key component that accelerates the airflow through rotation to generate thrust; the duct is similar to an airfoil duct, which not only guides the airflow, but also plays a role in gathering and diffusing the airflow.

[0004] The ducted fan system in the prior art mainly has the following technical problems: 1) Inner rotor high-speed motors are mainly used, and the motor speed is usually high (6000-10000rpm); therefore, although the noise and NVH problems of ducted fans are better than those of open propellers, the high-frequency noise and NVH problems of ducted fans still exist.

[0005] 2) There are many parts and many connecting components between different parts. The connections are complex and have low reliability, resulting in a high probability of failure. In addition, a cooling system is usually required to cool the motor, which increases the weight.

[0006] 3) Low integration, large size and heavy weight.

[0007] 4) Poor power scalability and compatibility in different application scenarios. Limited by the heat dissipation conditions of the electric propulsion system, the electric ducted fan propulsion system of the same design model can only be used in a narrow power level and cannot meet the needs of different power levels and application scenarios.

[0008] 5) Low system cooling efficiency. When an aircraft flies at high altitude, the speed relative to the air is very high (usually 20-100m / s). The motor is installed inside the duct nacelle, and high-speed forced air cooling cannot be effectively utilized; the motor controller is installed in the fuselage or wing, separated from the motor, and connected in the middle by a cooling pipe, the system cooling efficiency is low and the loss is large; the motor and controller are separated, which does not effectively benefit the most efficient heat dissipation components (fans and nacelles) of the duct; because the electric propulsion system generates heat when in use, it is usually necessary to design additional heat dissipation components for cooling. When additional heat dissipation structures are added, additional structural weight will be added, and the increased surface area of ​​the heat dissipation components will cause aerodynamic losses, increase resistance, and reduce system efficiency.

[0009] Based on this, the present invention designs a highly integrated, efficient cooling outer rotor motor ducted fan system to solve the above problems. Summary of the invention

[0010] In view of the above-mentioned shortcomings of the prior art, the present invention provides a highly integrated and efficient cooling outer rotor motor ducted fan system.

[0011] To achieve the above objectives, the present invention is implemented through the following technical solutions: A highly integrated, highly efficient cooling outer rotor motor ducted fan system comprises a motor stator winding, a fan outer rotor assembly formed integrally of fan blades and a motor outer rotor turntable, and an integrated housing formed integrally of a motor inner stator sleeve, a duct nacelle, a motor controller main housing of a motor controller, and a plurality of duct stator blades; a cooling structure is mounted on the integrated housing; the motor stator winding is fixedly connected to the outer wall at one end of the integrated housing, the front air guide cover is fixedly connected to the fan outer rotor assembly, and the rear air guide cover is mounted on the other end of the integrated housing; the integrated housing is rotatably connected to the fan outer rotor assembly; the cooling structure comprises a cooling water channel; a water inlet pipe and a water outlet pipe are fixedly mounted on the upper and lower ends of the outer wall at the other end of the integrated housing, a cooling water channel is provided inside the integrated housing, and the water inlet pipe and the water outlet pipe are respectively connected to the two ends of the cooling water channel.

[0012] Furthermore, the fan outer rotor integrated component is made of titanium alloy or aluminum alloy; the integrated shell is made of aluminum alloy or magnesium alloy.

[0013] Furthermore, the outer rotor of the motor includes a fan outer rotor integrated component, a rear bearing and a permanent magnet; the permanent magnet is fixed to the inner surface of the outer rotor turntable of the motor, and the stator sleeve inside the motor is rotationally connected to the outer rotor turntable of the motor through the front bearing and the rear bearing.

[0014] Furthermore, a plurality of groups of duct stator blades are evenly distributed between the duct nacelle and the main housing of the motor controller.

[0015] Furthermore, the motor controller includes a motor controller main shell, a motor controller side shell and a control element located on the motor controller main shell in the integrated shell; the motor controller side shell is fixedly installed on the side wall of the motor controller main shell; the water inlet pipe and the water outlet pipe are fixedly installed on the upper and lower ends of the side wall of the motor controller side shell.

[0016] Furthermore, a cooling structure is installed on the stator sleeve inside the motor and the main housing of the motor controller.

[0017] Furthermore, the stator sleeve inside the motor and the main shell of the motor controller are respectively provided with a cooling water channel 1 and a cooling water channel 2 which are connected to each other. The cooling water channel 1 and the cooling water channel 2 are integrated into a cooling water channel, and the water inlet pipe and the water outlet pipe are respectively connected to the two ends of the cooling water channel 2.

[0018] Furthermore, the motor stator winding is fixedly connected to the outer wall of the stator sleeve inside the motor.

[0019] Furthermore, the front air guide cover is fixedly connected to the front end of the outer rotor turntable of the motor.

[0020] Furthermore, the rear air deflector is fixedly mounted on the outer wall of the other end of the main housing of the motor controller.

[0021] Compared with the prior art, the present invention has the following beneficial effects: 1) The axial length of the duct nacelle is small: the fan blades and the motor outer rotor disc are integrated, which can greatly reduce the axial length of the duct nacelle, reduce the weight, and improve the power density.

[0022] 2) Reduce the impact of ducted fan noise: The ducted fan with an outer rotor motor can output a larger thrust at a lower speed. The characteristics of the outer rotor motor can effectively reduce the ducted speed, reduce bearing requirements, improve the NVH performance of the ducted fan, and be highly environmentally friendly. Due to the characteristics of the outer rotor motor, a higher torque can be output at a low speed, so that the ducted fan using an outer rotor motor can provide a large thrust to the aircraft at a lower speed (3000rpm-4000rpm). The ducted fan works at a low speed with low noise, and there is no high-frequency harsh noise of the ducted fan at a high speed, which greatly enhances the friendliness to the environment and passengers. At the same time, it is beneficial to the NVH performance of the ducted fan and the aircraft, and effectively reduces the vibration excitation of the ducted fan itself and the vibration excitation of the electric aircraft.

[0023] 3) High integration: By reducing the number of connecting parts, the volume and weight are reduced, and the power density is high; the fan blades and the outer rotor turntable of the motor are designed and manufactured in an integrated manner; the stator sleeve inside the motor, the duct nacelle, the main housing of the motor controller and the duct stator blades are integrated into one design; the motor controller and the motor are integrated, and the cooling water channel is integrated inside; the connecting parts are effectively reduced, and due to the integrated design, the parts can effectively reduce weight and volume, and the product has a high power density.

[0024] 4) High system reliability; simple structure, reduced parts and components, and low probability of system failure; due to the integrated design of parts, the present invention effectively reduces the failure risks caused by connecting components, parts themselves and fastening connections between different parts, and the system is simplified, thereby reducing the probability of failure.

[0025] 5) High system cooling efficiency; by integrating the fan blades and the motor outer rotor turntable and using metal materials with good thermal conductivity such as aluminum alloy / titanium alloy, the fan blades can be effectively used as excellent heat sinks to dissipate heat for the motor outer rotor, permanent magnet magnet steel, and rear bearing; by integrating the motor inner stator sleeve, duct nacelle, and duct stator blades and using metal materials with good thermal conductivity such as aluminum alloy / magnesium alloy, the duct nacelle and duct stator blades can be effectively used as heat sinks to dissipate heat for the motor inner stator sleeve and motor stator winding; by integrating the cooling water channel design, the number of connecting intermediate pipes and parts can be reduced, heat loss can be reduced, and cooling efficiency can be improved; 6) Strong power level compatibility and scalability: The present invention uses a hybrid cooling method of high-efficiency air cooling + water cooling, and the cooling method of the product can be adjusted to make the product of the present invention applicable to a wider power level; in the lower power application range of the motor (less than 80KW), the present invention can use a high-efficiency air cooling design solution alone to meet the application requirements of low-cost aircraft; in the higher power application range of the motor (80-250KW), the present invention can use a hybrid cooling (high-efficiency air cooling + integrated water cooling) solution to meet the application requirements under high-power conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the prior art descriptions are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention, and for ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0027] Figure 1 The three-dimensional diagram of the highly integrated outer rotor motor ducted fan system of the present invention is Figure 1 .

[0028] Figure 2 It is a front view of the highly integrated outer rotor motor ducted fan system of the present invention.

[0029] Figure 3 The three-dimensional diagram of the highly integrated outer rotor motor ducted fan system of the present invention is Figure 2 .

[0030] Figure 4 for Figure 2 AA section view.

[0031] Figure 5 It is a cross-sectional view of a fan outer rotor assembly formed integrally of fan blades and a motor outer rotor turntable.

[0032] Figure 6 It is a cross-sectional view of an integrated casing formed by the stator sleeve inside the motor, the duct nacelle, the motor controller main casing of the motor controller and multiple groups of duct stator blades.

[0033] The numbers in the figure represent: 1. Duct nacelle; 2. Air deflector; 3. Fan blades; 4. Duct stator blades; 5. Stator sleeve inside the motor; 6. Water inlet pipe; 7. Main housing of the motor controller; 8. Stator winding of the motor; 9. Rear bearing; 10. Water outlet pipe; 11. Cooling water channel; 12. Permanent magnet; 13. Motor outer rotor turntable; 14. Front bearing; 15. Rear air deflector; 16. Motor controller side housing; 17. Cooling water channel one; 18. Cooling water channel two; 19. Fan outer rotor integrated component; 20. Integrated housing. DETAILED DESCRIPTION

[0034] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0035] The terms “left”, “right”, “front”, “back”, “up” and “down” mentioned in the following description are oriented in the viewing direction of the front view.

[0036] Embodiment 1: In some embodiments, please refer to the drawings of the specification Figure 1-Figure 4 , a highly integrated, efficient cooling outer rotor motor ducted fan system, comprising a motor controller, a motor stator winding 8, a rear bearing 9, a permanent magnet 12, a front bearing 14, a fan outer rotor integrated component formed by a fan blade 3 and a motor outer rotor turntable 13, and an integrated housing 20 formed by a motor inner stator sleeve 5, a duct nacelle 1, a motor controller main housing 7 of a motor controller and a plurality of duct stator blades 4; Preferably, the fan blades 3 and the motor outer rotor turntable 13 are integrally manufactured using titanium alloy or aluminum alloy material, and the obtained part is a fan outer rotor integrated part 19; The present invention integrates two separately designed parts of the existing system, namely, the fan blades 3 and the motor outer rotor disk 13, into one part. Compared with the traditional ducted fan structure having separate fan blades and a central hub, the present invention uses the motor outer rotor disk 13 as the hub of the fan blades 3, which can reduce the number of fastening and connecting parts between the traditional separately designed fan blades 3 and the motor shaft; At the same time, since the fan blades 3 have a very high convection cooling speed relative to the air (usually in the range of 20-100 m / s) during the high-speed flight of the electric aircraft, the fan blades 3 are a natural heat sink. After the fan blades 3 and the motor outer rotor turntable 13 are designed and manufactured in an integrated manner, the fan blades 3 can be efficiently used as a heat sink to directly dissipate the heat of the motor outer rotor; The motor outer rotor includes a fan outer rotor integrated part 19, a rear bearing 9 and a permanent magnet 12; the motor adopts a surface-mounted outer rotor structure, and the permanent magnet 12 is fixed to the inner surface of the motor outer rotor turntable 13 by glue; the motor inner stator sleeve 5 is rotatably connected to the motor outer rotor turntable 13 through the front bearing 14 and the rear bearing 9; After being assembled into the motor outer rotor assembly, the fan outer rotor integrated part 19 can be used as a heat sink to dissipate heat from the permanent magnet magnetic steel 12 and the outer surface of the rear bearing 9; The motor controller includes a motor controller main housing 7, a motor controller side housing 16 and a control element located on the motor controller main housing 7 in an integrated housing 20; the motor controller side housing 16 is fixedly mounted on the side wall of the motor controller main housing 7; The duct stator blades 4 are evenly distributed between the duct nacelle 1 and the motor controller main housing 7. A cooling structure is installed on the motor inner stator sleeve 5 and the motor controller main housing 7, and the cooling structure includes a cooling water channel 11; the water inlet pipe 6 and the water outlet pipe 10 are fixedly installed on the upper and lower ends of the side wall of the motor controller side housing 16. The inside of the motor inner stator sleeve 5 and the motor controller main housing 7 are respectively provided with a connected cooling water channel 17 and a cooling water channel 2 18, and the cooling water channel 17 and the cooling water channel 2 18 are integrated into the cooling water channel 11, and the water inlet pipe 6 and the water outlet pipe 10 are respectively connected to the two ends of the cooling water channel 2 18.

[0037] Preferably, the duct stator blade 4 adopts a thin-walled support sheet structure.

[0038] The cooling water enters the water inlet pipe 6, first flows through the main housing 7 of the motor controller, and the cooling water channel 2 18 is used to cool some heating components of the motor controller (such as power devices, busbar capacitors, copper bars, etc.); then flows through the inside of the stator sleeve 5 in the motor, passes through the U-shaped cooling water channel 1 17, cools the stator, and then flows through the lower half of the cooling water channel 2 18 to the water outlet pipe 10 and flows out; The present invention integrates four parts of the existing system (the stator sleeve 5 in the motor, the duct nacelle 1, the duct stator blade 4, and the motor controller main housing 7) into an integrated housing part; the motor controller main housing 7 is used as the main housing of the motor controller, and the integrated housing 20 can be made of aluminum alloy / magnesium alloy materials to achieve the integration of the motor stator housing and the motor controller main housing; compared with the traditional split design, the motor has a separate housing, the motor controller has a separate housing, and the motor housing, the motor controller main housing and the center body hub need to be connected by connecting structures and fasteners. The integrated housing 20 can effectively reduce the intermediate connecting structures and parts, and at the same time can reduce the mass and improve the overall strength of the duct.

[0039] At the same time, since the electric aircraft has a very high convection cooling speed (usually in the range of 20-100 m / s) relative to the air during high-speed flight, the ducted stator blades 4 are located behind the ducted fan blades 3 in the duct. Due to the high-speed rotation of the fan blades 3, the high-speed airflow is blown to the ducted stator blades 4, so that the ducted stator blades 4 can be used as a better heat sink; the integrated housing can efficiently use the ducted nacelle 1 and the ducted stator blades 4 as heat sinks to dissipate heat from the motor stator and some heating elements of the motor controller; The motor stator winding 8 is fixedly connected to the outer wall of the motor inner stator sleeve 5, and the motor stator winding 8 is fixed to the motor inner stator sleeve 5 through processes such as hot embedding; the front air guide cover 2 is fixedly connected to the front end of the motor outer rotor turntable 13; the rear air guide cover 15 is fixedly connected to the outer wall of the motor controller main housing 7.

[0040] The heat generated by the motor stator winding 8 can be dissipated by an air-cooled radiator formed by the duct nacelle 1 and the duct stator blades 4 (the air-cooled radiator dissipates heat from the stator sleeve 5 in the motor, and then dissipates heat from the motor stator winding 8), or by a water channel through a cooling structure; During assembly, the fan outer rotor integrated component 19 and the integrated housing 20 are assembled first, and then the fan outer rotor integrated component 19 and the integrated housing 20 are assembled in a centering manner. After the multiple parts are integrated, the present invention can still ensure the smooth assembly of the assembly product, thereby ensuring the feasibility and effectiveness of the present invention.

[0041] The present invention has the following advantages: 1) The axial length of the duct nacelle 1 is small: the fan blades 3 and the motor outer rotor disc 13 are integrated, which can greatly reduce the axial length of the duct nacelle 1, reduce the weight, and improve the power density.

[0042] 2) Reduce the impact of ducted fan noise: The ducted fan with an outer rotor motor can output a larger thrust at a lower speed. The characteristics of the outer rotor motor can effectively reduce the ducted speed, reduce bearing requirements, improve the NVH performance of the ducted fan, and be highly environmentally friendly. Due to the characteristics of the outer rotor motor, a higher torque can be output at a low speed, so that the ducted fan using an outer rotor motor can provide a large thrust to the aircraft at a lower speed (3000rpm-4000rpm). The ducted fan works at a low speed with low noise, and there is no high-frequency harsh noise of the ducted fan at a high speed, which greatly enhances the friendliness to the environment and passengers. At the same time, it is beneficial to the NVH performance of the ducted fan and the aircraft, and effectively reduces the vibration excitation of the ducted fan itself and the vibration excitation of the electric aircraft.

[0043] 3) High integration: By reducing the number of connecting parts, the volume and weight are reduced, and the power density is high; the fan blades 3 and the motor outer rotor turntable 13 are designed and manufactured in an integrated manner; the motor internal stator sleeve 5, the duct nacelle 1, the motor controller main housing 7 and the duct stator blades 4 are designed in an integrated manner; the motor controller and the motor are designed in an integrated manner, and the cooling water channel is integrated internally; the connecting parts are effectively reduced, and due to the integrated design, the parts can effectively reduce weight and volume, and the product has a high power density.

[0044] 4) High system reliability; simple structure, reduced parts and components, and low probability of system failure; due to the integrated design of parts, the present invention effectively reduces the failure risks caused by connecting components, parts themselves and fastening connections between different parts, and the system is simplified, thereby reducing the probability of failure.

[0045] 5) The system has high cooling efficiency; by integrating the fan blades 3 and the motor outer rotor turntable 13 and using metal materials with good thermal conductivity such as aluminum alloy / titanium alloy, the fan blades 3 can be effectively used as an excellent heat sink to dissipate heat for the motor outer rotor, permanent magnet magnet 12, and rear bearing 9; by integrating the motor inner stator sleeve 5, duct nacelle 1, and duct stator blade 4 and using metal materials with good thermal conductivity such as aluminum alloy / magnesium alloy, the duct nacelle 1 and duct stator blade 4 can be effectively used as a heat sink to dissipate heat for the motor inner stator sleeve 5 and motor stator winding 8; by integrating the cooling water channel design, the number of connecting intermediate pipes and parts can be reduced, heat loss can be reduced, and cooling efficiency can be improved; 6) Strong power level compatibility and scalability: The present invention uses a hybrid cooling method of high-efficiency air cooling + water cooling, and the cooling method of the product can be adjusted to make the product of the present invention applicable to a wider power level; in the lower power application range of the motor (less than 80KW), the present invention can use a high-efficiency air cooling design solution alone to meet the application requirements of low-cost aircraft; in the higher power application range of the motor (80-250KW), the present invention can use a hybrid cooling (high-efficiency air cooling + integrated water cooling) solution to meet the application requirements under high-power conditions.

[0046] Embodiment 2: In some embodiments, as a preferred embodiment of the present invention, the front fairing 2 and the front end cover of the motor are integrated into an integrated design, referred to as the fairing end cover part; the fairing end cover is fixed to the stator sleeve 5 inside the motor of the integrated housing 20 by screws; the rear fairing 15 is fastened to the outer wall of the main housing 7 of the motor controller by fastening screws.

[0047] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. Such modifications or replacements will not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. Highly integrated, efficient cooling outer rotor motor ducted fan system, characterized by: The invention comprises a motor stator winding (8), a fan outer rotor integrated component (19) formed integrally of a fan blade (3) and a motor outer rotor rotating disk (13), and an integrated housing (20) formed integrally of a motor inner stator sleeve (5), a duct nacelle (1), a motor controller main housing (7) of a motor controller, and a plurality of groups of duct stator blades (4); a cooling structure is installed on the integrated housing (20); the motor stator winding (8) is fixedly connected to the outer wall of one end of the integrated housing (20), the front air guide cover (2) is fixedly connected to the fan outer rotor integrated component (19), and the rear air guide cover (15) is installed on the other end of the integrated housing (20); the integrated housing (20) is rotatably connected to the fan outer rotor integrated component (19); the cooling structure comprises a cooling water channel (11), and the cooling water channel (11) is opened inside the integrated housing (20).

2. The highly integrated, efficient cooling outer rotor motor ducted fan system according to claim 1, characterized in that: The fan outer rotor integrated component (19) is made of titanium alloy or aluminum alloy; the integrated housing (20) is made of aluminum alloy or magnesium alloy.

3. The highly integrated, efficient cooling outer rotor motor ducted fan system according to claim 2, characterized in that: The motor outer rotor comprises a fan outer rotor integrated component (19), a rear bearing (9) and a permanent magnet (12); the permanent magnet (12) is fixed to the inner surface of the motor outer rotor turntable (13), and the motor inner stator sleeve (5) is rotatably connected to the motor outer rotor turntable (13) via the front bearing (14) and the rear bearing (9).

4. The highly integrated, efficient cooling outer rotor motor ducted fan system according to claim 3, characterized in that: A plurality of groups of duct stator blades (4) are evenly distributed between the duct nacelle (1) and the motor controller main housing (7).

5. The highly integrated, efficient cooling outer rotor motor ducted fan system according to claim 4, characterized in that: The motor controller comprises a motor controller main housing (7), a motor controller side housing (16), and a control element located on the motor controller main housing (7) in an integrated housing (20); the motor controller side housing (16) is fixedly mounted on a side wall of the motor controller main housing (7); and the water inlet pipe (6) and the water outlet pipe (10) are fixedly mounted on the upper and lower ends of the side wall of the motor controller side housing (16).

6. The highly integrated, efficient cooling outer rotor motor ducted fan system according to claim 5, characterized in that: A cooling structure is installed on the stator sleeve (5) inside the motor and the main housing (7) of the motor controller.

7. The highly integrated, efficient cooling outer rotor motor ducted fan system according to claim 6, characterized in that: A first cooling water channel (17) and a second cooling water channel (18) are respectively provided in the interior of the stator sleeve (5) inside the motor and the main housing (7) of the motor controller. The first cooling water channel (17) and the second cooling water channel (18) are integrated into a cooling water channel (11). The water inlet pipe (6) and the water outlet pipe (10) are respectively connected to the two ends of the second cooling water channel (18).

8. The highly integrated, efficient cooling outer rotor motor ducted fan system according to claim 7, characterized in that: The motor stator winding (8) is fixedly connected to the outer wall of the stator sleeve (5) inside the motor.

9. The highly integrated, efficient cooling outer rotor motor ducted fan system according to claim 8, characterized in that: The front air guide cover (2) is fixedly connected to the front end of the motor outer rotor rotating disk (13).

10. The highly integrated, efficient cooling outer rotor motor ducted fan system according to claim 9, characterized in that: The rear air guide cover (15) is fixedly mounted on the outer wall of the motor controller main housing (7).

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