Axial flux motor phase change-liquid composite circulation cooling structure

Abstract

The application discloses an axial flux motor phase change-liquid composite circulation cooling structure and belongs to the technical field of motors. The axial flux motor phase change-liquid composite circulation cooling structure comprises a motor shell, a stator, a rotor and a cooling structure integrated in an inner shell. The motor shell comprises a coaxially arranged outer shell and an inner shell. The outer shell is provided with an outer shell liquid inlet, an outer shell liquid outlet and a liquid collecting groove. The liquid collecting groove is communicated with the outer shell liquid inlet, thereby forming an external liquid circulation loop. A plurality of I-shaped grooves are formed in the inner shell. The cooling structure comprises an I-shaped heat pipe and a liquid flow channel. The I-shaped heat pipe is radially inserted into a reserved gap of a stator winding of the stator and is embedded with the I-shaped grooves. The liquid flow channel is arranged along the circumference of the inner shell. The cold end of the I-shaped heat pipe is in contact with the liquid flow channel, and composite cooling is realized through phase change circulation and liquid circulation. The application can significantly reduce the temperature rise peak value in the motor through the characteristics of the phase change material in the motor, continuously and efficiently dissipate heat through the liquid cooling characteristics, and improve the heat dissipation efficiency and the motor reliability.

Description

Technical Field

[0001] This invention relates to the field of motor technology, and in particular to a phase change-liquid composite circulation cooling structure for an axial flux motor. Background Technology

[0002] Axial flux motors, as a type of electromagnetic energy conversion device with high power density and high efficiency, exhibit significant advantages in demanding applications such as new energy vehicles, aerospace, and industrial servo systems due to their axially distributed magnetic circuit design and compact overall structure. Compared to traditional radial flux motors, these motors can achieve higher torque output and better space utilization within the same volume.

[0003] However, while this unique structure brings excellent performance to the motor, it also faces a severe heat dissipation challenge. In particular, the tight arrangement of its disc-shaped configuration restricts the heat dissipation path in the axial direction. When the motor is under high speed or heavy load conditions, the heat concentrated in the windings and core is difficult to dissipate in time. The resulting excessive internal temperature rise not only damages the performance of the insulation material but also causes irreversible magnetic attenuation of the permanent magnets, thus directly affecting the motor's operational reliability and service life.

[0004] Currently, the cooling methods used in engineering practice mainly fall into three categories: air cooling, liquid cooling, and phase change cooling. Air cooling generally relies on external equipment such as fans to drive airflow for heat exchange, but this approach often increases the overall size of the machine and is accompanied by noise and pollution sensitivity issues. Liquid cooling, while possessing high heat transfer efficiency, faces leakage risks and media compatibility challenges due to its high system complexity. Phase change cooling technology relies on the mechanism by which materials absorb a large amount of latent heat during phase transitions, effectively suppressing temperature peaks in a short period. However, its inherently poor heat dissipation sustainability cannot meet the requirements for long-term stable operation of motors.

[0005] It is evident that existing cooling methods have not yet achieved a good balance between efficient heat dissipation and maintaining system compactness. There is an urgent need for a composite cooling structure that combines rapid cooling and sustained heat dissipation capabilities to meet the increasingly stringent heat dissipation requirements of modern high-performance axial flux motors. Summary of the Invention

[0006] The purpose of this invention is to provide an axial flux motor phase change-liquid composite circulation cooling structure to solve the above-mentioned technical problems existing in the prior art.

[0007] To achieve the above objectives, the present invention provides the following solution: an axial flux motor phase change-liquid composite circulation cooling structure, comprising a motor housing, a stator, a rotor, and a cooling structure integrated in an inner shell; the stator includes N non-connected un-yoke stator teeth and stator windings wound on the un-yoke stator teeth; the motor housing includes a coaxially arranged outer shell and an inner shell, the outer shell being provided with an outer shell liquid inlet, an outer shell liquid outlet, and a liquid collection tank, the liquid collection tank being connected to the outer shell liquid inlet to form an external liquid circulation loop; the inner shell having multiple I-shaped slots; all gaps between the inner shell and the stator windings are filled with epoxy resin material to form a continuous thermally conductive bridge; The cooling structure includes an I-shaped heat pipe and a liquid flow channel. The I-shaped heat pipe is inserted radially into the reserved gap of the stator winding of the stator and fits into the I-shaped slot. The liquid flow channel is arranged circumferentially along the inner shell. The cold end of the I-shaped heat pipe is wrapped by the wall of the liquid flow channel, and composite cooling is achieved through phase change circulation and liquid circulation. The liquid flow channel splits into two symmetrical semi-annular flow channels at the inlet and finally merges at the outlet. The portion of the liquid flow channel between two adjacent I-shaped heat pipes is a continuous flow channel. On one side of the transverse portion of the I-shaped heat pipe, it is divided into two, extending axially to the longitudinal portion of the I-shaped heat pipe respectively, and merges on the other side of the transverse portion, extending circumferentially to the next I-shaped heat pipe.

[0008] Furthermore, the I-shaped heat pipe is made of epoxy resin material and is internally encapsulated with liquid-gas phase change material.

[0009] Furthermore, the longitudinal portion of the I-shaped heat pipe is located at both ends of the transverse portion and is perpendicular to the transverse portion.

[0010] Furthermore, the gaps between the I-shaped heat pipe and the liquid flow channel, and the stator winding, are filled with epoxy resin material.

[0011] Furthermore, the number of I-shaped slots is the same as the number of stator slots, and the included angle between the centers of adjacent slots is 360° / N, where N is the number of stator slots.

[0012] Furthermore, the stator teeth without yokes are evenly distributed circumferentially, and the phase angle between two adjacent stator teeth without yokes is 360° / N.

[0013] Furthermore, the stator winding and the front and rear tooth shoes of the yokeless stator are respectively provided with space for I-shaped heat pipes to enter, and there is also space for I-shaped heat pipes to enter between two adjacent stator windings.

[0014] Furthermore, the liquid collection tank is connected to the liquid inlet of the outer casing via a liquid pump and a filter.

[0015] Compared with the prior art, the present invention discloses at least the following beneficial effects:

[0016] This invention achieves rapid and direct heat transfer from the core heat source to the heat pipe by directly inserting an I-shaped heat pipe radially into the reserved gap of the stator winding and fitting it into the I-shaped slot of the inner shell. This allows the hot end of the heat pipe to closely contact the high heat flux density area such as the winding. The heat pipe is encapsulated with a liquid-gas phase change material, which absorbs a large amount of latent heat during the phase change process, thus quickly suppressing the instantaneous temperature rise peak during motor operation. At the same time, the cold end of the heat pipe is wrapped by the liquid flow channel wall arranged circumferentially on the inner shell. The liquid flow channel adopts a design that splits into two symmetrical semi-annular flow channels at the liquid inlet and eventually merges. This allows the coolant to surround the cold end of each heat pipe and form a uniform and efficient forced convection heat transfer, continuously and stably exporting the heat absorbed by the phase change to the external circulation loop. This tightly coupled structure of "deep heat source - rapid heat absorption by phase change - continuous heat dissipation by liquid flow" significantly shortens the heat transfer path and reduces contact thermal resistance and overall thermal resistance. Thus, within a limited axial space, it synergistically improves the heat dissipation speed, continuity and uniformity, ultimately effectively reducing the internal operating temperature of the motor and improving heat dissipation efficiency and the reliability of long-term motor operation. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of a phase change cooling structure for an axial disc permanent magnet motor in the prior art.

[0019] Figure 2 A schematic diagram of the phase change-liquid composite circulation cooling structure of the axial flux motor provided in an embodiment of the present invention;

[0020] Figure 3 This is a schematic diagram of the overall structure of the cooling structure according to an embodiment of the present invention;

[0021] Figure 4 This is a schematic diagram of the internal structure of the cooling structure according to an embodiment of the present invention;

[0022] Figure 5 The isometric view of the cooling structure after removing the outer and inner shells in an embodiment of the present invention. Figure 1 ;

[0023] Figure 6 The isometric view of the cooling structure after removing the outer and inner shells in an embodiment of the present invention. Figure 2 ;

[0024] Figure 7 This is a schematic diagram of the inner shell in the cooling structure of an embodiment of the present invention;

[0025] Figure 8 This is a schematic diagram of the stator structure in the cooling structure of an embodiment of the present invention;

[0026] Figure 9 This is a schematic diagram of the I-shaped heat pipe in the cooling structure of an embodiment of the present invention;

[0027] Figure 10 This is a schematic diagram of the liquid flow channel in the cooling structure of an embodiment of the present invention.

[0028] In the diagram: 100, vent; 200, shaft; 1, motor housing; 10, outer shell; 11, outer shell body; 12, outer shell liquid inlet; 13, outer shell liquid outlet; 14, liquid collection tank; 15, filter; 16, liquid pump; 17, motor shaft; 20, inner shell; 21, inner shell body; 22, I-shaped slot; 23, epoxy resin material; 3, stator; 31, stator teeth; 32, stator winding; 4, rotor; 41, rotor yoke; 42, permanent magnet; 5, cooling structure; 51, I-shaped heat pipe; 511, transverse section; 512, longitudinal section; 52, liquid flow channel; 53, flow channel liquid inlet; 54, flow channel liquid outlet. Detailed Implementation

[0029] 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 embodiments of the present invention, and not all embodiments. Based on the 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.

[0030] In the development of high-power-density motors, axial flux motors have become a research hotspot due to their compact structure and high torque density. To pursue even higher power density and efficiency, stator-yoke-less structures are widely adopted, but this structure also introduces severe thermal management challenges. On the one hand, the high flux density saturation in the toothed shoe region leads to a significant increase in iron losses; on the other hand, the windings at the slot opening generate substantial eddy current losses due to the skin effect and proximity effect, and the combined effect of these two factors easily creates localized hot spots around the toothed shoe. More critically, eliminating the stator yoke significantly reduces the heat dissipation path and increases the heat transfer distance. Furthermore, the close arrangement of the windings within the slots severely hinders heat dissipation, leading to heat accumulation within the slots. This not only restricts the continuous improvement of motor performance but also accelerates insulation aging, causing reliability issues. Existing cooling solutions often struggle to effectively dissipate heat for such special structures.

[0031] For example, prior art with patent publication number CN119483113A proposes a phase change cooling method and structure for an axial disc permanent magnet motor, such as... Figure 1As shown, this structure utilizes the kinetic energy generated by the rotation of the shaft 200 to drive airflow. The air is cooled by a phase change material inside the shaft 200 before entering the air gap between the stator and rotor, cooling both surfaces, and then exiting through the exhaust port 100 on the back of the rotor. This improves cooling efficiency and reduces costs. However, the airflow path inside the motor is complex. Improper design can lead to localized airflow obstruction, affecting the uniformity of heat dissipation. Furthermore, this method relies on the rotation of the shaft 200 to generate airflow; when the motor speed is low, the airflow intensity may be insufficient, resulting in decreased cooling efficiency and making it difficult to maintain high-efficiency cooling for extended periods.

[0032] For example, prior art patent CN119787725A proposes a hybrid cooling structure for a multi-torque component axial flux motor and an axial flux motor itself. This method involves attaching heat-conducting plates to the surfaces of the permanent magnet and stator core windings. However, these plates only contact the surface of the components and cannot penetrate deep into the winding gaps, making it difficult to effectively dissipate the core heat accumulated in the slots. Furthermore, the heat dissipation path is a multi-segment conduction, resulting in a long path, high thermal resistance, and low efficiency. In addition, the cooling channel is a simple annular design, with the cooling medium flowing mostly in a laminar state, without optimization for high heat flux density areas, resulting in limited heat exchange efficiency. Moreover, the overall design is not integrated with the electromagnetic field distribution characteristics, failing to achieve precise cooling resource allocation and potentially leading to uneven cooling. Therefore, designing an efficient and compact heat dissipation solution for yokeless axial flux motors that can penetrate deep into the heat source, shorten the heat transfer path, and be optimized in conjunction with the electromagnetic design has become a key technical challenge in overcoming its power density and reliability bottlenecks.

[0033] To address the aforementioned technical problems of current axial flux motors, this invention proposes a phase-change-liquid composite circulating cooling structure for axial flux motors and an axial flux motor incorporating this structure. By combining the direct contact between the I-shaped heat pipe and the windings with the cold-end liquid cooling channel in the housing, the peak temperature rise of the axial flux motor can be effectively suppressed, while continuous and efficient heat dissipation can be achieved, significantly improving the stability of motor operation.

[0034] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0035] Reference Figures 2 to 10 As shown, this embodiment provides a phase change-liquid composite circulation cooling structure for an axial flux motor, including a motor housing 1, a stator 3, a rotor 4, and a cooling structure 5 integrated in the inner shell 20. Overall, the cooling structure 5 achieves rapid heat absorption through direct contact between the I-shaped heat pipe 51 and the stator winding 32, and combined with the continuous heat transport via the liquid flow channel 52, forms a highly efficient dual-circulation heat dissipation system. This system can significantly suppress internal temperature rise under high-speed and high-load conditions, ensuring long-term stable operation.

[0036] In embodiments of the present invention, such as Figures 2 to 6 As shown, the motor housing 1 constitutes the main support and protection structure of the motor. The motor housing 1 includes an outer shell 10 and an inner shell 20 arranged coaxially. The motor shaft 17 passes through the entire motor housing 1, connecting the rotor 4 and the external transmission system to achieve power transmission. The outer shell 10 serves as the outermost protective structure, with its body 11 being a cavity structure. The top of the outer shell 11 has a liquid inlet 12, and the bottom has a liquid outlet 13 and a recessed collection tank 14. The collection tank 14 stores coolant, which is circulated by a liquid pump 16 located outside the outer shell 10. After being purified by a filter 15, the coolant flows in from the outer shell inlet 12 and finally returns to the collection tank 14 through the outer shell outlet 13, forming an external liquid circulation loop.

[0037] A liquid pump 16 and a filter 15 are installed on the outside of the housing 10. The liquid pump 16 pumps the coolant out of the collection tank 14, so that it flows through the filter 15 to remove impurities, and then enters the motor housing 1 through the liquid inlet 12 of the housing to participate in the cooling cycle. Finally, the coolant that has absorbed heat flows back to the collection tank 14 through the liquid outlet 13 of the housing, thus forming a stable external liquid circulation loop, which is responsible for finally carrying the heat accumulated inside the motor to the external environment for dissipation.

[0038] In this embodiment of the invention, the inner shell 20 is fixedly installed inside the outer shell 10, serving as a key component supporting the cooling structure 5. For example... Figure 4 and 7 As shown, the main structure of the inner shell 20 is an annular inner shell body 21. Multiple I-shaped slots 22 are evenly distributed on the circumferential surface of the inner shell body 21 for radially inserting and fixing the I-shaped heat pipe 51. The included angle between the centers of adjacent I-shaped slots 22 is 360° / N, where N is the number of stator slots. Furthermore, a liquid flow channel 52 is embedded within the inner shell body 21. The liquid flow channel 52 is arranged circumferentially along the inner shell body 21, branching into two symmetrical semi-annular flow channels at the flow channel inlet 53, and finally converging at the flow channel outlet 54. Except for the liquid flow channel 52 itself, all gaps between the inner shell 21 and the stator winding 32 are filled with epoxy resin material 23 with high thermal conductivity, forming a continuous thermal bridge that both fixes the I-shaped heat pipe 51 and the stator winding 32 and reduces contact thermal resistance.

[0039] In one specific embodiment, the path of the liquid flow channel 52 is specially designed: the section between two adjacent I-shaped heat pipes 51 is a continuous flow channel; when the flow channel extends to the transverse portion 511 of the I-shaped heat pipe 51, it splits into two streams, which extend to the longitudinal portion 512 respectively and cover the longitudinal portion 512, and then rejoin on the other side of the transverse portion 511 and continue to flow circumferentially to the next I-shaped heat pipe 51, thereby achieving full coverage and efficient heat exchange of the end (cold end) of the I-shaped heat pipe 51.

[0040] like Figure 6 , Figure 10 As shown, the liquid flow channel 52 is a closed channel precisely machined inside the inner shell body 21, and it is arranged around the circumference of the motor. After the coolant enters from the flow channel inlet 53, it immediately splits into two streams, flowing in opposite directions (clockwise and counterclockwise), and finally merges at a symmetrical position and flows out from the flow channel outlet 54.

[0041] The shape and path of the liquid flow channel 52 are highly matched with the cold end morphology of the I-shaped heat pipe 51. When the flow channel extends to the transverse portion 511 of the heat pipe, it splits into two streams and axially wraps around the longitudinal portion 512. This bent structure has been optimized by fluid dynamics, which can disrupt laminar flow and enhance turbulence intensity without significantly increasing the system pressure drop, thereby greatly improving the convective heat transfer coefficient of the fluid-solid interface. Combined with the symmetrical dual-channel split design, it ensures that the coolant can circulate rapidly and uniformly cover all the cold ends of the heat pipe, overcoming the shortcomings of low heat transfer efficiency and mismatch with heat load distribution in traditional simple annular flow channels, and achieving a synergistic improvement in heat dissipation capacity and flow efficiency.

[0042] In embodiments of the present invention, such as Figure 5 As shown, the rotor 4, as the rotating component of the motor, includes a rotor yoke 41 and a permanent magnet 42. The rotor yoke 41 and the permanent magnet 42 together constitute the magnetic pole unit of the rotor 4. Its structural design takes into account the integrity of the magnetic circuit, the reliability of mechanical strength, and the high efficiency of heat dissipation. The rotor 4 is connected to the motor shaft 17 by bolts or interference fits to achieve effective power output.

[0043] In one specific embodiment, the rotor yoke 41 is typically made of a soft magnetic material with high permeability (such as silicon steel sheet) and has a disk-shaped structure. Its function is to form part of the magnetic circuit, guide and concentrate the magnetic field, and provide a reliable mounting base for the permanent magnet 42. To further reduce weight and enhance heat dissipation, the rotor yoke 41 may have a hollow design or an internal auxiliary air duct.

[0044] In one specific embodiment, multiple permanent magnets 42 are uniformly attached or embedded along the circumferential direction of the rotor yoke 41. Specifically, the permanent magnets 42 can be arranged according to a specific polarity rule to form the excitation magnetic field required by the motor. In axial flux motors, the permanent magnets 42 are usually fan-shaped to adapt to the spatial constraints of the disc structure.

[0045] In embodiments of the present invention, such as Figure 6 and Figure 8 As shown, the stator 3 adopts a yokeless modular design, which consists of N independent and circumferentially distributed yokeless stator teeth 31 and stator windings 32 wound on them. The included angle between the stator teeth 31 is also 360° / N.

[0046] In embodiments of the present invention, such as Figures 6 to 10 As shown, the cooling structure 5 mainly consists of an I-shaped heat pipe 51 and a liquid flow channel 52. The I-shaped heat pipe 51 is radially embedded in the I-shaped slot 22 of the inner shell 20, with its outer contour glued or interference-fitted to the I-shaped slot 22. The I-shaped heat pipe 51 and the liquid flow channel 52 are thermally connected using a "cold end-wall coupling" method. The cold end of the I-shaped heat pipe 51 is wrapped by the wall of the liquid flow channel 52, with high thermal conductivity epoxy resin used for bonding in between, forming a wall coupling that only transfers heat and not mass, thus achieving rapid transfer of phase change heat to the liquid cooling system.

[0047] In some implementations, while the yokeless structure improves power density, it also presents significant heat dissipation challenges: the toothed shoe region experiences a surge in iron losses due to magnetic flux saturation, and the slotted winding generates substantial eddy current losses under the skin effect, easily leading to localized hot spots. Traditional cooling methods struggle to effectively conduct heat deep into the winding gaps. This solution addresses this unique structure by pre-leaving a gap between the I-shaped heat pipe 51 and the stator winding 32, allowing it to be radially inserted into the winding to directly contact the heat source. Simultaneously, the liquid flow channel 52 directly wraps around the cold end of the heat pipe, perfectly matching the axial disc configuration. This achieves efficient heat dissipation from the internal core region without increasing axial space, solving the problems of limited heat dissipation paths and high thermal resistance inherent in traditional structures.

[0048] like Figure 9 As shown, the I-shaped heat pipe 51 has an "I"-shaped structure, including a horizontal section 511 and a vertical section 512 vertically connected to both sides of the horizontal section 511. Specifically, the vertical section 512 is embedded inside the toothed shoe, which can efficiently dissipate heat from the toothed shoe and slot area; the horizontal section 511 is placed between adjacent windings, which can not only provide targeted cooling for the heat accumulated in the slot windings, but also play a physical isolation role, reducing the risk of short circuits between windings. By integrating the heat pipe units at the toothed shoe and the slot windings, an I-shaped integrated cooling unit, namely the I-shaped heat pipe 51, can be formed. When local hot spots occur, the remaining part of the heat pipe can be used as a cold end for heat dissipation, significantly improving the overall heat conduction capacity of the system.

[0049] To ensure the smooth insertion of the I-shaped heat pipe 51, the stator winding 32, during winding, leaves gaps adapted to the shape of the I-shaped heat pipe 51 between the stator teeth 31 and adjacent windings. This allows the I-shaped heat pipe 51 to be inserted radially into the reserved gaps and simultaneously embedded in the I-shaped slot 22 of the inner shell body 21, forming a tight physical contact. The I-shaped heat pipe 51 is correspondingly arranged circumferentially and inserted radially into these reserved spaces. At the same time, the end (cold end) of the I-shaped heat pipe 51 is also radially embedded into the corresponding I-shaped slot 22 on the inner shell body 21, thereby achieving its secure installation in the entire radial thickness direction of the motor.

[0050] The I-shaped heat pipe 51 is not a simple uniformly distributed cooling element, but is designed based on electromagnetic field-temperature field coupling analysis. Its longitudinal portion 512 is embedded in the tooth shoes on both sides of the stator tooth 31, and its transverse portion 511 is inserted between adjacent stator windings 32. This arrangement, through precise calculation of winding loss distribution, directly positions the I-shaped heat pipe 51 in the high heat flux density region where iron and copper losses are most concentrated, achieving precise allocation of cooling resources. This "magnetic-thermal fusion" design enables the I-shaped heat pipe 51 to quickly absorb and transfer core heat, significantly reducing the risk of local overheating and improving heat dissipation efficiency.

[0051] In one specific embodiment, the I-shaped heat pipe 51 is made of epoxy resin material and encapsulates a liquid-gas phase change material inside. When the motor is working, the heat generated by the stator winding 32 is rapidly conducted to the I-shaped heat pipe 51, causing the phase change material inside to vaporize. The vapor flows to the cold end of the heat pipe (i.e., the end near the liquid flow channel 52) under the action of pressure difference, where it releases heat to the coolant in the flow channel through the epoxy resin material 23, and then condenses and flows back to the hot end, completing a continuous phase change cycle.

[0052] In one specific embodiment, such as Figure 6 As shown, to ensure extremely low thermal resistance heat transfer between the stator winding 32, the I-shaped heat pipe 51, and the liquid flow channel 52, all assembly gaps between components in this structure, such as the tiny gaps between the I-shaped heat pipe 51 and the stator winding 32, between the I-shaped heat pipe 51 and the I-shaped slot 22, and between the wall of the liquid flow channel 52 and the surrounding metal, have been completely filled with epoxy resin material 23. This not only enhances the mechanical stability of the overall structure but also significantly improves the thermal conductivity between components.

[0053] During operation, the cooling structure implements a dual thermal management mechanism: on the one hand, the I-shaped heat pipe 51 utilizes the latent heat of phase change to quickly absorb peak heat in the winding region, effectively mitigating instantaneous temperature rise; on the other hand, the coolant in the liquid flow channel 52 flows continuously under the drive of the liquid pump 16, absorbing heat directly transferred from the cold end of the heat pipe and the epoxy resin filling layer along the way, ultimately carrying the accumulated heat energy to the outside of the motor for dissipation. This composite cooling strategy overcomes the shortcomings of poor sustainability of simple phase change cooling and avoids the deficiencies of slow response and easy leakage of a single liquid cooling system, thus achieving efficient and long-lasting heat dissipation performance within a limited space, significantly improving the operational reliability and service life of the axial flux motor.

[0054] In summary, this structure achieves rapid heat absorption by extending deep into the winding via I-shaped heat pipes 51, which, combined with a highly coupled liquid flow channel 52, continuously dissipates heat, forming an integrated dual-circulation heat dissipation system. This not only physically shortens the heat transfer path from the heat source to the cooling medium and reduces the thermal resistance of multi-stage conduction, but also allows the cooling effect to directly act on the electromagnetic hotspot through a magnetothermal fusion layout. The I-shaped structure itself enables each heat pipe unit to form a multi-cold-end synergistic heat dissipation effect in both the axial and circumferential directions, further improving the uniformity of heat diffusion and overall heat conduction capacity. Therefore, this solution effectively solves the problems of heat accumulation in the slots and localized overheating of the gear shoes caused by the compact structure of yokeless axial flux motors, providing key technical guarantees for the reliable operation of high-power-density motors.

[0055] In the description of this invention, it should be understood that the terms "longitudinal", "lateral", "up", "down", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this invention, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0056] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. An axial flux motor phase change-liquid hybrid cycle cooling structure, characterized by, The motor housing (1), the stator (3), the rotor (4) and the cooling structure (5) integrated in the inner shell (20) are included. The stator (3) includes N non-connected yokeless stator teeth (31) and a stator winding (32) wound on the yokeless stator teeth (31). The motor housing (1) includes a coaxial outer shell (10) and an inner shell (20), the outer shell (10) is provided with an outer shell liquid inlet (12), an outer shell liquid outlet (13) and a liquid collecting groove (14), the liquid collecting groove (14) is communicated with the outer shell liquid inlet (12) to form an external liquid circulation loop; a plurality of I-shaped grooves (22) are formed on the inner shell (20); all gaps between the inner shell body (21) of the inner shell (20) and the stator winding (32) are filled with epoxy resin material (23) to form a continuous heat conduction bridge. The cooling structure (5) includes an I-shaped heat pipe (51) and a liquid flow channel (52); the I-shaped heat pipe (51) is inserted into the reserved gap of the stator winding (32) of the stator (3) along the radial direction and is embedded with the I-shaped groove (22); the liquid flow channel (52) is arranged along the circumference of the inner shell (20); the cold end of the I-shaped heat pipe (51) is wrapped by the wall surface of the liquid flow channel (52), and composite cooling is realized through phase change circulation and liquid circulation; the liquid flow channel (52) is divided into two symmetrical half-ring flow channels at the flow channel liquid inlet (53) and is finally converged at the flow channel liquid outlet (54); the part of the liquid flow channel (52) between adjacent two I-shaped heat pipes (51) is a continuous flow channel, one side of the transverse part (511) of the I-shaped heat pipe (51) is divided into two parts, respectively extends to the longitudinal part (512) of the I-shaped heat pipe (51) along the axial direction, and converges on the other side of the transverse part (511) and extends to the next I-shaped heat pipe (51) along the circumference.

2. The axial flux motor phase change-liquid hybrid cycle cooling structure according to claim 1, wherein, The I-shaped heat pipe (51) is made of epoxy resin material (23) and encapsulates liquid-gas phase change material inside.

3. The axial flux motor phase change-liquid hybrid cooling structure according to claim 1 or 2, characterized in that, The longitudinal part (512) of the I-shaped heat pipe (51) is arranged at both ends of the transverse part (511) and is perpendicular to the transverse part (511).

4. The axial flux motor phase change-liquid hybrid cycle cooling structure according to claim 1, wherein, The gap between the I-shaped heat pipe (51) and the liquid flow channel (52), the stator winding (32) is filled with epoxy resin material (23).

5. The axial flux motor phase change-liquid hybrid cooling structure of claim 1, wherein, The number of the I-shaped grooves (22) is the same as the number of the stator slots of the stator (3), and the center angle of adjacent grooves is 360° / N, wherein N is the number of stator slots.

6. The axial flux motor phase change-liquid hybrid cooling structure according to claim 5, wherein, The yokeless stator teeth (31) of the stator (3) are uniformly distributed along the circumference, and the angle difference between adjacent two yokeless stator teeth (31) is 360° / N.

7. The axial flux motor phase change-liquid hybrid cooling structure according to claim 6, wherein, The stator winding (32) and the front and rear tooth shoes of the yokeless stator tooth (31) respectively leave spaces for the I-shaped heat pipe (51) to enter, and the space for the I-shaped heat pipe (51) to enter is also left between adjacent two stator windings (32).

8. The axial flux motor phase change-liquid hybrid cycle cooling structure of claim 1, wherein, The liquid collecting groove (14) is connected with the outer shell liquid inlet (12) through a liquid pump (16) and a filter (15).

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