Lightweight high-protection forced air-cooled heat dissipation axial flux evtol motor

Abstract

This invention relates to a lightweight, highly protected forced-air-cooled axial flux EVTOL motor, belonging to the field of motor technology. It includes a stator assembly, a rotor assembly, and a central barrel connecting the upper and lower rotors. The stator assembly includes a motor shaft, a stator support frame, and a yokeless motor core. Enamelled coils are wound on the motor core. The stator support frame is machined from aluminum alloy in a single process, incorporating a stator skeleton, bearing housing, and heat dissipation fins on the outer circumference of the stator skeleton. The rotor assembly includes an upper rotor and a lower rotor located on opposite axial sides of the stator assembly. The upper and lower rotors each have machined rotor inlets and outlets, centrifugal blades, and mounted magnet backing irons. Permanent magnets are mounted on the magnet backing irons. The upper and lower rotors are fixedly connected and rotate synchronously via the central barrel. This axial flux motor features a unified design of lightweight, high protection, and efficient heat dissipation, solving the technical problem of conflict between cooling methods and protection levels. It is particularly suitable for the reliability and power requirements of EVTOL aircraft under complex operating conditions.

Description

Technical Field

[0001] This invention relates to an axial flux motor, specifically a lightweight, highly protected forced air-cooled axial flux evtol motor, belonging to the field of motor technology. Background Technology

[0002] With the rise of the Urban Air Mobility (UAM) concept, electric vertical takeoff and landing (eVTOL) aircraft have seen rapid development in recent years as a key technological solution for addressing urban congestion and achieving green travel. As the core power source of eVTOLs, the propulsion motor not only needs extremely high power density (lightweight) to meet the aircraft's payload and range requirements, but also must possess extremely high reliability and safety to adapt to complex operating conditions such as frequent takeoffs, cruises, and landings. Currently, eVTOL propulsion systems mainly use radial flux motors. However, in pursuit of higher torque density and more compact axial dimensions, axial flux motors (also known as disc motors) have gradually become a research hotspot in the eVTOL field due to their flattened structure and higher power density advantages. Although axial topology has a natural advantage in lightweighting, it still faces many technical bottlenecks in practical applications.

[0003] In existing technologies, axial flux motors mainly suffer from the following problems: First, heat dissipation bottlenecks and thermal imbalance. The air gap of an axial flux motor is planar, and the stator is usually located in the center, making it easy for heat to accumulate. At high power density output, the windings and stator core generate huge heat flux. If the heat cannot be dissipated in time, it will not only cause irreversible demagnetization of the permanent magnet, but also severely restrict the motor's continuous power output capability, affecting flight safety. Second, there is a conflict between cooling methods and protection levels. Although traditional liquid cooling solutions have high heat dissipation efficiency, they require complex sealing structures and piping systems, increasing... The added weight and the risk of leakage in the harsh aviation vibration environment, while the common open forced air cooling is simple in structure and light in weight, it is difficult to meet the high protection level required by eVTOL motor in harsh environments such as high altitude, high humidity, and sand and dust. Foreign objects can easily enter the air gap inside the motor, causing insulation damage or mechanical jamming. Thirdly, there is a contradiction between lightweight and structural rigidity. In order to further reduce weight, the thickness of the motor housing and end cover is often compressed, but this may lead to insufficient structural rigidity of the motor at high torque output, affecting the uniformity of the air gap, and thus causing vibration and noise, or even rotor rubbing.

[0004] Therefore, how to design an axial flux motor that combines lightweight design, high protection level, and efficient forced air cooling capability, that is, to ensure the cleanliness of the motor interior and efficiently dissipate heat from the windings and ends without the need for a heavy liquid cooling system, is a technical problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a lightweight, highly protected, forced-air-cooled axial flux eVTOL motor. While achieving high power density, it also ensures efficient air cooling and high protection performance. It features high structural integration, light weight, and strong reliability, making it suitable for aerospace power applications such as eVTOL.

[0006] The technical solution of this invention to solve the technical problem is as follows: A lightweight, highly protected forced air-cooled axial flux eVTOL motor includes a stator assembly, a rotor assembly, and a sealing and protection assembly. The stator assembly includes a motor shaft, a stator support frame, a yokeless core, and windings; The stator support frame is an integrally formed structure of aluminum alloy or other high-strength thermally conductive metal, integrating the stator frame, bearing chamber and outer ring heat dissipation fins, realizing the integration of structural support, bearing installation and heat dissipation functions. The yokeless core and windings are fixed and encapsulated in the stator frame by potting compound or thermally conductive injection molding material, and the heat from the windings is directly conducted to the heat dissipation fins through the thermally conductive medium.

[0007] The rotor assembly is a dual-rotor single-stator structure, including an upper rotor and a lower rotor; Both the upper and lower rotors are integrally formed with rotor air inlets, rotor centrifugal blades, and magnet back iron mounting positions; The upper and lower rotors are fixedly connected by the motor's central barrel and rotate synchronously. The motor's inner barrel is equipped with centrifugal blades and ventilation holes, which, as the rotor rotates, create a centrifugal fan effect, constructing an internal closed air duct.

[0008] The sealing and protection assembly includes a stator sealing ring, a stator sealing strip, and a bearing housing sealing strip, forming a sealing structure at both ends of the stator and the bearing position. This ensures the air-cooled duct is sealed and circulated while preventing external moisture and dust from entering the motor.

[0009] Furthermore, the stator support frame is integrally formed from aluminum alloy or other high-strength thermally conductive metal, and simultaneously undertakes the triple functions of structural support, bearing installation, and heat dissipation.

[0010] Furthermore, the upper and lower rotors have rotor air inlets at their centers and rotor air outlets near the middle barrel, which are connected to the vent holes of the middle barrel to form a closed forced air cooling duct with axial air intake and radial air outlet.

[0011] Furthermore, the centrifugal blades and vents in the middle barrel are alternately distributed circumferentially, generating a centrifugal suction effect when rotating, which enhances the airflow velocity and heat exchange efficiency in the heat dissipation fin area.

[0012] Furthermore, the sealing and protection assembly forms a labyrinth-type or close-fitting seal at both ends of the stator, allowing airflow inside the duct while isolating it from the outside, thus achieving high protection and compatibility with forced air cooling.

[0013] The beneficial effects of this invention are: Integrated stator support: Integrates structure, heat dissipation, and bearings into one unit, significantly reducing the number of parts, improving rigidity, and significantly reducing weight.

[0014] Closed forced air cooling system: Dual rotors and a middle barrel together form a centrifugal fan. Airflow enters from the air inlets at both ends and washes the heat dissipation fins along the closed air duct, resulting in high heat dissipation efficiency and eliminating the need for liquid cooling.

[0015] High protection and air-cooling compatibility: The sealed structure isolates only the external environment without obstructing the internal airflow. It achieves a high IP protection level while maintaining efficient heat dissipation, resolving the contradictions of traditional air cooling not being dustproof and liquid cooling being heavy and prone to leakage.

[0016] Integrated heat dissipation and demagnetization prevention: Airflow simultaneously cools the windings, stator, and permanent magnet back iron, reducing the operating temperature of the permanent magnet, preventing irreversible demagnetization, and improving the continuous power and reliability of the motor.

[0017] Highly adaptable to eVTOL: lightweight, high power density, high protection, and high reliability, meeting the stringent operating conditions and safety requirements of aircraft. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the overall structure of the present invention; Figure 2 This is a schematic diagram of the exploded structure of the present invention; Figure 3 This is an axial sectional view of the present invention; Figure 4 This is a cross-sectional view of the rotor and the middle barrel assembly of the present invention; Figure 5 This is a schematic diagram of the stator assembly structure of the present invention; Figure 6 This is a cross-sectional view of the rotor structure of the present invention; Figure 7 This is a diagram showing the positional relationship of the rotor centrifugal blades of the present invention.

[0019] Explanation of reference numerals in the attached figures: 01 Motor Shaft 02 Unyoke core 03 Winding 04 Stator frame 05 Bearing Chamber 06 Heat dissipation fins 07 Upper Rotor 08 Lower Rotor 09 Rotor air inlet 10. Rotor centrifugal blades 11. Magnetic back iron 12 Centrifuge blades in the middle drum 13 Vent holes 14 Motor barrel 15 Stator sealing ring 16 Stator sealing strip 17 Bearing housing sealing strip 18 Rotor air outlet 19 Air ducts Detailed Implementation

[0020] The principles and features of the present invention are described below with reference to the accompanying drawings. The examples given are only for explaining the present invention and are not intended to limit the scope of the present invention.

[0021] like Figure 1 As shown in Figure 7, the motor of the present invention includes a stator assembly, a rotor assembly, and a sealing and protection assembly.

[0022] The stator assembly includes a motor shaft 01, a stator support frame, a yokeless core 02, and a winding 03; The stator support frame is integrally formed from the stator frame 04, bearing chamber 05, and heat dissipation fins 06; The yokeless core 02 and the winding 03 are fixed in the stator frame 04 by potting or injection molding process, and the heat conduction medium quickly conducts the heat of the winding to the heat dissipation fins 06.

[0023] The rotor assembly includes an upper rotor 07 and a lower rotor 08, which are located on both sides of the stator axial direction, respectively. Both the upper rotor 07 and the lower rotor 08 are integrally formed with a rotor air inlet 09, rotor centrifugal blades 10 and a magnet back iron 11. The two rotors are rigidly connected by the motor barrel 14 and rotate synchronously; The motor's inner barrel 14 is equipped with centrifugal blades 12 and vent holes 13, which form a centrifugal fan when rotating, driving airflow to circulate inside.

[0024] The sealing and protection assembly includes a stator sealing ring 15, a stator sealing strip 16, and a bearing housing sealing strip 17. The sealing structure forms a closed protection at both ends of the stator, preventing external moisture and dust from entering, while the internal air duct 19 remains unobstructed.

[0025] During operation, the rotor and the middle barrel rotate at high speed. Under centrifugal force, external cold air is drawn in from the upper and lower rotor air inlets 09, flows along the air duct 19 through the heat dissipation fins 06 and the back iron of the magnet 11, and after carrying away the heat, it is discharged through the vent 13 and the rotor air outlet 18. The sealed structure maintains high protection for the stator and winding areas, achieving a balance between liquid-free cooling, lightweight design, strong heat dissipation, and high protection.

[0026] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. All modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A lightweight, highly protected forced-air-cooled axial flux eVTOL motor, characterized in that, include: The system comprises a stator assembly, a rotor assembly, and a central barrel. The stator assembly includes a motor shaft, a stator support frame, and a yokeless iron core. Enamelled wire coils are wound around the yokeless iron core. The stator support frame is integrally formed from aluminum alloy or high-strength thermally conductive material, constituting a thermally conductive stator skeleton. A bearing chamber and heat dissipation fins are integrally integrated onto the thermally conductive stator skeleton. The heat dissipation fins are formed on the outer circumference of the outer circle of the thermally conductive stator skeleton. Thermally conductive filler is filled between the yokeless iron core and the thermally conductive stator skeleton, fixing and supporting the yokeless iron core and coils, and transferring all the heat from the stator operation to the thermally conductive stator skeleton, which is then dissipated outwards through the heat dissipation fins on the outer circle of the skeleton. An upper bearing, a lower bearing, and a support bearing are installed in the bearing chamber. The bearings are transition-fitted with the motor shaft and drive the rotor assembly. The rotor assembly includes an upper rotor and a lower rotor located on both sides of the stator assembly along the axial direction. Both the upper and lower rotors are integrally formed from aluminum alloy or high-strength thermally conductive material, and integrally integrate rotor air inlets and outlets, built-in centrifugal blades, and a wind-guiding reinforcement structure. The rotor air inlets and outlets include an upper rotor air inlet and a lower rotor air inlet located in the center region of the rotor's axial end face, and an air outlet located on the outside of the rotor. The built-in centrifugal blades and wind-guiding reinforcement structure are radially and evenly distributed along the rotor's radial direction. Their height, in conjunction with the magnet back iron, forms a closed cavity air duct structure, constructing a high-strength rotor with a large thickness to resist axial attraction during motor operation and prevent rotor deformation. A magnet back iron is fixedly mounted on the rotor, and a permanent magnet is installed on the magnet back iron. The magnet back iron, in conjunction with the rotor's built-in centrifugal blades and wind-guiding reinforcement structure, encloses and forms a sealed air duct relative to the stator surface. The middle barrel has an annular cylindrical structure and is coaxially connected to the upper rotor. The system includes an upper rotor and a lower rotor; the middle barrel has blades and air duct vents on its wall surface; the middle barrel is fixedly connected to the upper and lower rotors and rotates synchronously with them; when the motor is running, the main airflow flows in through the air inlets of the upper and lower rotors, flows through the sealed air ducts to the stator heat dissipation fins, absorbs heat, and is then accelerated and discharged through the blades and air duct vents of the middle barrel; it also includes a sealing and protection assembly, which includes an upper stator sealing strip, a lower stator sealing strip, a stator upper and lower rotor sealing ring retainer, and a stator bearing housing sealing strip; the upper and lower stator sealing strips are respectively disposed on the axial end faces of the heat-conducting stator frame and are sealed to the corresponding rotor end faces; the stator sealing ring retainer, together with the sealing strips, forms a radial sealing structure between the stator and the rotor, creating a sealed protection state inside the stator; the stator bearing housing sealing strip is sleeved on the edge of the bearing housing port to seal the gap between the bearing housing and the bearing.

2. The axial flux eVTOL motor according to claim 1, characterized in that, The heat dissipation fins of the thermally conductive stator frame are in a ring array structure, and their cross-sectional shape is one or more combinations of straight, arc or wedge shapes.

3. The axial flux eVTOL motor according to claim 1, characterized in that, The blades and air vents of the middle barrel are arranged alternately and evenly along the circumference; the cross-sectional shape of the blades is one or more combinations of straight, arc, or arc-shaped surfaces.

4. The axial flux eVTOL motor according to claim 1, characterized in that, The thermally conductive filler is a high thermal conductivity epoxy resin or a non-metallic thermosetting filler thermally conductive material, which is filled between the yokeless iron core and the thermally conductive stator frame to form an integral thermally conductive structure.

5. The axial flux eVTOL motor according to claim 1, characterized in that, The height of the rotor's built-in centrifugal blades and air-guiding reinforcement structure is assembled with the magnet back iron, so that the rotor as a whole forms a high-thickness rigid structure; the built-in centrifugal blades and air-guiding reinforcement structure are radial protrusions or flow channels integrally machined on the inner side of the rotor housing, which are used to guide airflow to cool the permanent magnet and magnet back iron, and enhance the strength of the rotor structure.

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