Oil-cooled heat-dissipation double-rotor axial flux motor

Abstract

This invention relates to the field of flux motor heat dissipation technology, and discloses an oil-cooled dual-rotor axial flux motor, comprising: a stator including a frame, a stator support fixedly connected to the frame, and a stator core with windings; the frame having an oil inlet and an oil outlet; the stator support having an annular flow channel communicating with the oil inlet; the stator support having multiple fixed teeth arranged in a circular array, with radial flow channels penetrating through the fixed teeth and communicating with the annular flow channels; a sealing shell including a sealing ring fitted around the stator support and windings, and an upper sealing plate and a lower sealing plate respectively disposed at the top and bottom of the sealing ring and connected to the frame; and a rotor including a rotor housing fitted around the sealing ring, and an upper rotor disc and a lower rotor disc respectively disposed at the top and bottom of the rotor housing. This motor can achieve uniform distribution of cooling oil in the gap between the windings and the core, solving the problems of uneven heat dissipation, obvious hot spots, and low power density in existing motors.

Description

Technical Field

[0001] This invention relates to the field of flux motor heat dissipation technology, and in particular to an oil-cooled dual-rotor axial flux motor. Background Technology

[0002] As drones and eVTOL aircraft develop towards higher payload, longer endurance, and higher speeds, the performance requirements for their power systems and motors have significantly increased. Motors need to possess high power density (higher output power per unit volume), high efficiency (reduced energy loss), high reliability (adapting to harsh environments such as high altitude, low temperature, and vibration), and high safety (avoiding localized overheating that could lead to insulation failure or fire). Traditional air cooling or natural cooling methods can no longer meet the thermal management needs of high-power-density motors. Oil cooling, with its advantages of high efficiency, good dielectric insulation, and adaptability to complex operating conditions, has become the mainstream direction for heat dissipation in aircraft motors.

[0003] Existing oil-cooled motors mostly employ methods such as directly flushing oil onto the outer surface of the stator or slotting oil channels inside the stator core. However, these methods have the following drawbacks: First, uneven heat dissipation: Due to the simple design of the cooling oil flow path, such as a single channel or asymmetrical flow path, there are large differences in the cooling oil flow rate in different areas of the winding or between the winding and the core, making it easy for hot spots to form in local areas. Second, limited power density: To avoid overheating, traditional motors need to reduce the current density or the winding fill factor, making it difficult to increase the output power per unit volume. Third, complex structure: Some solutions increase the size and weight of the motor by adding additional cooling pipes or complex flow channel structures, which contradicts the lightweight requirements of aircraft.

[0004] Furthermore, for dual-rotor axial flux motors, since the stator is located in the middle and the rotor is on the upper and lower sides of the stator, the heat dissipation space is more compact, and the heat generated by the windings and the iron core is concentrated in the stator slots. Traditional radial or axial flow channels cannot accurately cover the core heat-generating area. Summary of the Invention

[0005] This invention proposes an oil-cooled dual-rotor axial flux motor to address the shortcomings of the prior art. This motor can achieve uniform distribution of cooling oil in the gap between the winding and the iron core, solving the problems of uneven heat dissipation, obvious hot spots, and low power density in existing motors.

[0006] The technical solution of this invention is: an oil-cooled dual-rotor axial flux motor, comprising: a stator, a sealing shell, and a rotor. The stator includes a frame, a stator support fixedly connected to the frame, and a stator core with windings disposed on the stator support. The frame has an oil inlet and an oil outlet. The stator support has multiple fixed teeth arranged in a circular array. The stator support has an annular flow channel communicating with the oil inlet. The fixed teeth have through radial flow channels communicating with the annular flow channels. The sealing shell includes a sealing ring fitted around the stator support and windings, and an upper sealing plate and a lower sealing plate respectively disposed at the top and bottom of the sealing ring and connected to the frame. The sealing ring, the upper sealing plate, and the lower sealing plate form an annular sealing cavity. The rotor includes a rotor housing fitted around the sealing ring, and an upper rotor disk and a lower rotor disk respectively disposed at the top and bottom of the rotor housing. The upper rotor disk is rotatably connected to the frame, and the frame extends through the lower rotor disk.

[0007] In at least one embodiment of the present invention, the oil inlet and oil outlet are respectively connected to an oil inlet pipe and an oil outlet pipe, the oil inlet pipe is connected to an oil supply pump, the oil outlet pipe is connected to an oil radiator, and the outlet of the oil radiator is connected to the inlet of the oil supply pump, so that the motor can operate during operation.

[0008] In at least one embodiment of the present invention, the base includes a column and an annular platform integrally formed on the column, the oil outlet extends longitudinally through the annular platform, and the top of the oil outlet is flush with the upper surface of the stator support.

[0009] In at least one embodiment of the present invention, the lower sealing plate is in contact with the bottom of the stator support.

[0010] In at least one embodiment of the present invention, the base is a hollow column, the bottom of the upper rotor disk is provided with a rotor shaft that extends into the base and is rotatably connected by a bearing, and the lower rotor disk has a mounting hole through which the base passes.

[0011] In at least one embodiment of the present invention, the sealing ring, the upper sealing plate and the lower sealing plate are bonded to each other, and the upper sealing plate and the lower sealing plate are bonded to the machine base.

[0012] In at least one embodiment of the present invention, the sealing ring, the upper sealing plate and the lower sealing plate are made of polyimide or polyetheretherketone, and the adhesive used for the sealing ring, the upper sealing plate and the lower sealing plate is epoxy resin adhesive or silicone sealant.

[0013] Compared with the prior art, the beneficial effects of the present invention are: The oil-cooled dual-rotor axial flux motor proposed in this invention allows cooling oil to flow in from the oil inlet of the motor base and into the annular flow channel at the inner diameter of the stator support. Subsequently, radial flow channels on multiple fixed teeth evenly distribute the cooling oil, ensuring it reaches the gaps between windings or between the windings and the stator core. Finally, the oil flows towards the heat-generating core area near the air gap on the inner diameter side of the stator, carrying the heat from this area. The cooling oil then exits the motor through the oil outlet at the top of the motor base. A sealing shell strictly restricts the flow of cooling oil within the internal components of the stator. Compared to existing technologies, this oil-cooled dual-rotor axial flux motor, through its circumferentially distributed radial flow channels, allows for even distribution of cooling oil to all areas of the windings, avoiding localized cooling. The hot spots caused by insufficient current distribution in the windings and core result in a more balanced temperature distribution, extending the life of the insulation material. Uniform heat dissipation allows for higher current densities and core magnetic flux density in the windings, enabling higher power output in the same volume, or reducing motor size for the same power output, thus minimizing efficiency losses due to temperature rise. Eliminating the risk of localized overheating avoids safety accidents such as insulation breakdown, short circuits, or fires caused by hot spots, better meeting the high reliability requirements of aircraft. The integrated flow channel design of the stator core support eliminates the need for additional external cooling pipes, fully utilizing the internal space of the stator and meeting the compact layout requirements of dual-rotor axial flux motors, making it particularly suitable for the lightweight, small-volume power system requirements of UAVs / eVTOLs. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the main structure of the present invention.

[0015] Figure 2 This is a schematic diagram of the stator structure of the present invention.

[0016] Figure 3 This is a schematic diagram of the rotor structure of the present invention.

[0017] Figure 4 This is a schematic diagram of the stator support structure of the present invention. Figure 1 .

[0018] Figure 5 This is a schematic diagram of the stator support structure of the present invention. Figure 2 .

[0019] Figure 6 This is a top sectional view of the structure of the present invention.

[0020] Explanation of reference numerals in the attached figures: 1. Stator; 11. Frame; 111. Oil inlet; 112. Oil outlet; 12. Stator support; 121. Fixed gear; 122. Annular flow channel; 123. Radial flow channel; 13. Winding; 14. Stator core; 15. Oil inlet pipe; 16. Oil outlet pipe; 2. Sealing shell; 21. Sealing ring; 22. Upper sealing plate; 23. Lower sealing plate; 3. Rotor; 31. Rotor shell; 32. Upper rotor disc; 321. Rotor shaft; 33. Lower rotor disc; 34. Rotor core; 35. Permanent magnet. Detailed Implementation

[0021] The accompanying drawings in this invention are not strictly drawn to scale, and the specific dimensions and quantity of each structure can be determined according to actual needs. The drawings described in this invention are merely structural schematic diagrams.

[0022] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the described embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0023] Unless otherwise defined, the technical or scientific terms used herein should have the ordinary meaning understood by one of ordinary skill in the art to which this invention pertains. The terms "first," "second," and similar terms used in this invention do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Terms such as "comprising" or "including" mean that the element or object preceding the word encompasses the elements or objects listed following the word and their equivalents, without excluding other elements or objects. Terms such as "inner," "outer," "upper," "lower," "far," "near," "front," and "rear" are used only to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0024] The existing motor stator core has an axial through hole (through the core teeth and yoke), through which cooling oil flows directly into the core, while the stator winding ends are cooled by external oil channels.

[0025] The differences from this invention are as follows: First, the flow channel location: The cooling oil mainly flows through the axial through-holes inside the iron core, without a dedicated, uniformly distributed flow channel designed for the gap between the windings and the iron core (especially at the junction of the winding ends and the iron core yoke); this invention, however, precisely guides the oil to the gap between the windings (the core heat-generating area) through the radial flow channels of the stator iron core support. Second, uniformity: The flow distribution of the axial through-holes depends on the iron core's own structure (which may have local blockages or differences in flow resistance), making it impossible to guarantee uniform cooling oil flow in different areas of the windings (such as the ends of different teeth); this invention achieves uniform flow distribution through circumferentially distributed radial flow channels, resulting in more uniform heat dissipation.

[0026] This invention aims to provide a stator oil-cooled heat dissipation structure for a dual-rotor axial flux motor. By optimizing the flow channel design of the stator core support, the cooling oil is evenly distributed in the gap between the winding and the core, solving the problems of uneven heat dissipation, obvious hot spot switching, and low power density of existing motors. Ultimately, it improves the motor's heat dissipation capacity, power density, efficiency, and safety, meeting the high reliability power system requirements of UAVs / eVTOL aircraft.

[0027] Combination Figures 1 to 6 As shown, an oil-cooled dual-rotor axial flux motor includes: The stator 1 includes a frame 11, a stator bracket 12 fixedly connected to the frame 11, and a stator core 14 with windings 13 mounted on the stator bracket 12. The frame 11 has an oil inlet 111 and an oil outlet 112. The stator bracket 12 has multiple fixed teeth 121 arranged in a circular array. The stator bracket 12 has an annular flow channel 122 communicating with the oil inlet 111. After cooling oil is pumped in from the oil inlet 111 of the frame 11, it first enters this annular flow channel 122. The tooth 121 is provided with a through radial flow channel 123, which is connected to the annular flow channel 122. The radial flow channels 123 are evenly distributed circumferentially along the radial direction of the stator support 12 (perpendicular to the plane of the annular flow channel 122) (e.g., 12 to 20, the specific number is adjusted according to the motor parameters). One end of each radial flow channel 123 is connected to the annular flow channel 122, and the other end extends to the outer edge of the stator support 12 (near the gap area between the winding 13 and the stator core 14). The stator support 12 is the core structure for achieving uniform oil cooling. Specifically, the stator core 14 is made of magnetic material to provide the magnetic circuit; the winding 13 is wound around the teeth of the stator core 14 and generates a rotating magnetic field after being energized, which is one of the main heat sources of the motor.

[0028] The sealing shell 2 includes a sealing ring 21 fitted around the stator support 12 and winding 13, and an upper sealing plate 22 and a lower sealing plate 23 respectively disposed at the top and bottom of the sealing ring 21 and connected to the machine base 11. The sealing ring 21, the upper sealing plate 22 and the lower sealing plate 23 form an annular sealing cavity. The sealing shell 2 strictly restricts the flow of cooling oil in the internal components of the stator 1 (stator support 12 flow channel, winding 13 gap, etc.) and completely isolates it from the rotor 3. This not only improves the cooling efficiency, but also eliminates the resistance consumption and energy loss caused by the interaction between the rotor 3 and the coolant.

[0029] like Figure 3 As shown, the rotor 3 includes a rotor housing 31 fitted outside the sealing ring 21, and an upper rotor disk 32 and a lower rotor disk 33 respectively disposed on the top and bottom of the rotor housing 31. The upper rotor disk 32 is rotatably connected to the base 11, and the base 11 extends through the lower rotor disk 33. The upper rotor disk 32 and the lower rotor disk 33 are provided with rotor cores 34 and permanent magnets 35 on opposite sides.

[0030] The flow channel connection relationship of the oil-cooled dual-rotor axial flux motor proposed in this invention is as follows: After the cooling oil flows in from the oil inlet 111 of the base 11, it passes through the following channels in sequence: oil inlet 111 at the bottom of the base 11 → annular flow channel 122 at the inner diameter of the stator support 12 → multiple radial flow channels 123 (evenly distributing the flow rate) → gaps between windings 13 and between windings 13 and stator core 14 (oil flows through the ends of windings 13 and the surface of stator core 14) → finally flows to the inner diameter side of stator 1 (near the heat-generating core area of ​​the air gap) → and is discharged from the motor through the oil outlet 112 at the top of the base 11.

[0031] The design of the sealing shell 2 of this invention has the following innovative features: 1. Complete isolation from rotor 3: The sealing shell 2 maintains a complete isolation boundary with the rotors 3 on both sides. The cooling oil is strictly confined inside the stator 1 and does not come into contact with the rotor 3, rotor shaft 321, bearings or any rotor-related components. This eliminates the resistance consumption, oil churning loss and additional mechanical resistance caused by the interaction between the cooling oil and the rotor 3 in traditional oil-cooled motors. 2. Precise cooling path: The sealed design ensures that the cooling oil only flows through the annular flow channel 122, radial flow channel 123 and the gap between the winding 13 and the stator core 14, which are the internal heat-generating areas of the stator 1. The cooling oil flow path is clear and optimized, avoiding the cooling oil from flowing into non-heat-generating areas or the area in contact with the rotor 3, thus improving the cooling efficiency. 3. Elimination of resistance and energy loss: By completely isolating the rotor 3 from the cooling oil, the frictional resistance (oil churning loss) between the rotor 3 and the coolant during rotation and the additional resistance of the cooling oil to the movement of the rotor 3 are eliminated. At the same time, unnecessary flow and energy consumption of the cooling oil around the rotor 3 are avoided, which significantly improves the mechanical efficiency of the motor. Even under the harsh operating conditions of high-speed rotation, vibration and temperature changes of the motor, the cooling oil can still maintain a completely isolated state from the rotor 3.

[0032] As an alternative embodiment, the oil inlet 111 and the oil outlet 112 are respectively connected to the oil inlet pipe 15 and the oil outlet pipe 16. The oil inlet pipe 15 is connected to the oil supply pump, and the oil outlet pipe 16 is connected to the oil radiator. Specifically, the outlet of the oil radiator is connected to the inlet of the oil supply pump so that during the operation of the motor, the cooling oil flowing out of the motor is cooled and then re-entered into the motor to achieve a cooling cycle.

[0033] As an alternative embodiment, the base 11 includes a column and an annular platform integrally formed on the column, with an oil outlet 112 extending longitudinally through the annular platform and the top of the oil outlet 112 being flush with the upper surface of the stator support 12; the above-mentioned limitation enables the cooling oil carrying heat to flow completely out of the motor during operation, fully carrying away the heat generated during motor operation.

[0034] As an alternative embodiment, the lower sealing plate 23 is attached to the bottom of the stator bracket 12; the stator bracket 12 provides stable support and fixation for the lower sealing plate 23 and the entire sealing shell 2, thereby ensuring the stability of the motor during operation.

[0035] As an alternative embodiment, the base 11 is a hollow column, the bottom of the upper rotor disk 32 is provided with a rotor shaft 321 that extends into the base 11 and is rotatably connected by a bearing, and the lower rotor disk 33 has a mounting hole through which the base 11 passes; the upper sealing plate 22 and the lower sealing plate 23 are both connected to the base 11 to ensure that the cooling oil is sealed only in the entire stator 1 during operation.

[0036] As an alternative embodiment, the sealing ring 21, the upper sealing plate 22 and the lower sealing plate 23 are bonded to each other, and the upper sealing plate 22 and the lower sealing plate 23 are bonded to the base 11, thereby constructing a closed cooling space that only contains the stator components (stator core 14, winding 13, stator support 12).

[0037] As an alternative embodiment, the sealing ring 21, the upper sealing plate 22, and the lower sealing plate 23 are made of thin-walled materials such as polyimide or polyetheretherketone, which are oil-resistant, high-temperature resistant, and have good insulation properties. The adhesive used for the sealing ring 21, the upper sealing plate 22, and the lower sealing plate 23 is a high-viscosity, oil-resistant, and temperature-resistant adhesive such as epoxy resin or silicone sealant.

[0038] The working principle and usage method of this embodiment: In the oil-cooled dual-rotor axial flux motor proposed in this invention, the sealing shell 2 ensures that the cooling oil is strictly confined within the enclosed space inside the stator 1, completely isolated from the rotor 3. Driven by an oil pump, the cooling oil enters from the oil inlet 111 at the bottom of the base 11, first filling the annular flow channel 122 at the inner diameter of the stator support 12 (ensuring stable oil pressure). Subsequently, it is dispersed to various directions at approximately the same flow rate and volume through the circumferentially distributed radial flow channels 123, uniformly penetrating into the gap between the winding 13 and the stator core 14 (especially the heat-generating areas that are easily overlooked in traditional solutions, such as the ends of the winding 13 and the teeth of the stator core 14). After carrying away the heat from the copper losses (I²R) of the winding 13 and the iron losses (hysteresis / eddy currents) of the stator core 14, the oil flow finally collects from the inner diameter side of the stator 1 and is discharged through the oil outlet 112 of the base 11, completing the heat transfer (the heat can be dissipated to the environment through an external oil-cooled radiator). Throughout the cooling process, the cooling oil only flows through the stator core 14, stator support 12 and winding 13 and other internal heat-generating components of the stator, without contacting the rotors 3 on both sides, rotor shaft 321, bearings and other related components. This not only efficiently removes the heat generated by the stator, but also eliminates the resistance and energy loss caused by the interaction between the rotor 3 and the coolant, thus improving the overall efficiency of the motor.

[0039] The above embodiments are merely specific implementations of the present invention, used to illustrate the technical solutions of the present invention, and not to limit them. The protection scope of the present invention is not limited thereto. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that any person skilled in the art can still modify or easily conceive of changes to the technical solutions described in the foregoing embodiments within the technical scope disclosed in the present invention, or make equivalent substitutions for some of the technical features; and these modifications, changes, or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions implemented in the present invention, and should all be covered within the protection scope of the present invention.

Claims

1. An oil-cooled dual-rotor axial flux motor, characterized in that, include: The stator includes a frame, a stator bracket fixedly connected to the frame, and a stator core with windings disposed on the stator bracket. The frame has an oil inlet and an oil outlet. The stator bracket has an annular flow channel communicating with the oil inlet. The stator bracket has a plurality of fixed teeth arranged in a circular array. The fixed teeth have a through radial flow channel, which communicates with the annular flow channel. The sealing shell includes a sealing ring fitted around the stator support and windings, and an upper sealing plate and a lower sealing plate respectively disposed at the top and bottom of the sealing ring and connected to the machine base. The sealing ring, the upper sealing plate and the lower sealing plate form an annular sealing cavity. The rotor includes a rotor housing fitted outside a sealing ring and an upper rotor disk and a lower rotor disk respectively disposed at the top and bottom of the rotor housing. The upper rotor disk is rotatably connected to the base, and the base extends through the lower rotor disk.

2. The oil-cooled dual-rotor axial flux motor as described in claim 1, characterized in that, The oil inlet and oil outlet are respectively connected to an oil inlet pipe and an oil outlet pipe. The oil inlet pipe is connected to an oil supply pump, and the oil outlet pipe is connected to an oil radiator. The outlet of the oil radiator is connected to the inlet of the oil supply pump so that the motor can operate normally.

3. The oil-cooled dual-rotor axial flux motor as described in claim 1, characterized in that, The base includes a column and an annular platform integrally formed on the column. The oil outlet extends longitudinally through the annular platform, and the top of the oil outlet is flush with the upper surface of the stator support.

4. The oil-cooled dual-rotor axial flux motor as described in claim 1, characterized in that, The lower sealing plate is fitted to the bottom of the stator support.

5. The oil-cooled dual-rotor axial flux motor as described in claim 1, characterized in that, The upper rotor disk has a rotor shaft at its bottom that extends into the machine base and is rotatably connected by a bearing, and the lower rotor disk has a mounting hole through which the machine base passes.

6. The oil-cooled dual-rotor axial flux motor as described in claim 1, characterized in that, The sealing ring, the upper sealing plate, and the lower sealing plate are bonded to each other, and the upper sealing plate and the lower sealing plate are bonded to the machine base.

7. The oil-cooled dual-rotor axial flux motor as described in claim 6, characterized in that, The sealing ring, upper sealing plate, and lower sealing plate are made of polyimide or polyetheretherketone.

8. The oil-cooled dual-rotor axial flux motor as described in claim 6, characterized in that, The adhesive used for the sealing ring, upper sealing plate, and lower sealing plate is epoxy resin or silicone sealant.

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