An axial flux permanent magnet motor with high-efficiency heat dissipation based on a heat sink

Abstract

This invention provides an axial flux permanent magnet motor with high-efficiency heat dissipation based on a heat spreader, belonging to the technical field of axial flux permanent magnet motors. The permanent magnet motor includes a housing and a stator assembly, a rotor assembly, a bearing assembly, and thermally conductive epoxy resin disposed inside the housing. The stator assembly is located on the inner bottom surface of the housing, and the rotor assembly is connected to the housing via the bearing assembly. The thermally conductive epoxy resin is disposed between the inner surface of the housing and the stator assembly. A heat spreader is also disposed inside the housing, located between the inner bottom surface of the housing and the stator assembly. This invention's axial flux permanent magnet motor utilizes a heat spreader-based high-efficiency cooling structure to establish an efficient heat transfer path from the high-heat-generating stator winding coils to the high-heat-dissipating housing, rapidly transferring most of the heat to the housing via the heat spreader and thermally conductive epoxy resin. Furthermore, the flat rotor core of the axial flux permanent magnet motor utilizes a natural fan during rotation to enhance rotor heat dissipation.

Description

Technical Field

[0001] This invention relates to the field of axial flux permanent magnet motor technology, and more specifically to an axial flux permanent magnet motor based on high-efficiency heat dissipation using a heat exchange plate. Background Technology

[0002] In the field of robotics, with increasing demands for space utilization efficiency, flat-design motors such as axial flux permanent magnet motors are gradually becoming the focus. These motors have attracted widespread attention due to their compact structure and high efficiency, making them particularly suitable for applications with limited installation space. However, as motors evolve towards higher power density, higher torque density, and lighter weight, effectively managing the heat generated during motor operation has become a key challenge for improving their performance, reliability, and lifespan. During motor operation, internal losses inevitably lead to heat generation, which not only affects motor efficiency but also causes material aging, decreased insulation performance, and other problems, thus shortening the motor's lifespan. Therefore, developing an efficient heat dissipation system is crucial for maintaining stable motor operation and extending its lifespan. Traditional heat dissipation methods, such as adding heat sinks or using forced ventilation fans, can alleviate temperature rise to some extent, but these methods may no longer be sufficient for modern motors that demand high performance.

[0003] In recent years, researchers have begun exploring methods to create additional heat dissipation paths between key heat-generating components of motors and the cooling housing to enhance heat dissipation. For example, thermally conductive insulating materials such as thermally conductive resins, adhesives, and ceramics are used to fill the gaps between the motor end windings and the housing, constructing additional heat conduction paths. This method can effectively transfer heat from the heat source to the cooling surface, but its effectiveness is limited by the type and amount of filler used, as well as the thermal conductivity of the matrix material itself. For high-performance motors that need to withstand extreme operating conditions, existing materials and technologies may not provide sufficient heat dissipation support.

[0004] Therefore, future research should focus on developing more efficient heat dissipation solutions to meet the heat dissipation requirements of motors operating under high power and high torque conditions. Summary of the Invention

[0005] The purpose of this invention is to provide an axial flux permanent magnet motor with high-efficiency heat dissipation based on a heat exchange plate, so as to solve the problem of poor heat dissipation effect of existing axial flux permanent magnet motors in the prior art.

[0006] To achieve the above objectives, an axial flux permanent magnet motor with high-efficiency heat dissipation based on a heat exchange plate is provided. The permanent magnet motor includes: a housing and a stator assembly, a rotor assembly, a bearing assembly, and thermally conductive epoxy resin disposed inside the housing. The stator assembly is disposed on the inner bottom surface of the housing, the rotor assembly is connected to the housing through the bearing assembly, and the thermally conductive epoxy resin is disposed between the inner surface of the housing and the stator assembly. A heat exchange plate is also disposed inside the housing, located between the inner bottom surface of the housing and the stator assembly.

[0007] The heat spreader is annular and has a two-layer structure. The upper layer is the evaporation end, and the lower layer is the condensation end. The vapor chamber formed by the connection of the evaporation end and the condensation end is used to store the liquid working fluid. Multiple wicking cores are set between the evaporation end and the condensation end. The multiple wicking cores are evenly distributed along the circumference of the heat spreader. Capillary microchannels are set in the vapor chamber. The capillary microchannels are designed with a spider web biomimetic structure. The capillary microchannels are distributed along the circumference of the condensation end and diverge from the center of the evaporation end to the edge. Vapor channels are formed between the multiple wicking cores.

[0008] Furthermore, the absorbent core has a porous structure and a honeycomb-like appearance; the absorbent core is located at the connection of adjacent capillary microchannels.

[0009] Furthermore, a placement groove is provided on the inner bottom surface of the casing, and the placement groove is filled with interfacial heat-conducting material; the heat spreader is placed in the placement groove, and the evaporation end of the heat spreader is glued to the stator assembly, while the condensation end of the heat spreader abuts against the interfacial heat-conducting material in the placement groove.

[0010] Furthermore, the stator assembly includes a stator core and an armature winding. The stator core is annular, and the stator core back yoke is bonded to the inner bottom surface of the housing and the evaporation end of the heat spreader. The stator core has multiple stator slots evenly distributed along its circumference, and the armature winding is embedded in the stator slots.

[0011] Furthermore, the housing is provided with an end cap, which is detachably connected to the housing by fixing screws.

[0012] Furthermore, the bearing assembly includes: a first bearing housing, a first bearing, a second bearing housing, and a second bearing. The first bearing housing is located on the end cover; the first bearing is located within the first bearing housing; the second bearing housing is located on the housing; and the second bearing is located within the second bearing housing.

[0013] Furthermore, the rotor assembly includes: a rotating shaft, a rotor core, and permanent magnets; the rotating shaft is connected to the housing via a first bearing and a second bearing; the rotor core is fixedly connected to the rotating shaft; multiple permanent magnets are attached to the rotor core, and the permanent magnets are located between the rotor core and the stator core, with an air gap between the stator core and the permanent magnets.

[0014] Furthermore, the rotor core has multiple ribs on the side where the permanent magnet is located.

[0015] Compared with the prior art, the present invention has the following advantages:

[0016] This invention relates to an axial flux permanent magnet motor based on a high-efficiency cooling structure using a heat spreader. This structure establishes a highly efficient heat transfer path from the high-heat-generating stator winding coils to the high-heat-dissipating housing. Most of the heat is rapidly transferred to the housing via the heat spreader and thermally conductive epoxy resin. Furthermore, the flat rotor of the axial flux permanent magnet motor utilizes a natural fan effect during rotation to enhance rotor cooling. Compared to traditional permanent magnet motors that rely on natural heat dissipation, this significantly shortens the internal heat conduction path, increases the heat transfer coefficient of the stator, and improves the heat transfer efficiency of the stator core, winding coils, and rotor assembly. This increases the motor's lifespan and allows it to handle larger currents, thereby generating greater power. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying 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 the overall structure of an axial flux permanent magnet motor.

[0019] Figure 2 This is a schematic diagram of the overall structure of an axial flux permanent magnet motor.

[0020] Figure 3 This is an overall cross-sectional view of an axial flux permanent magnet motor.

[0021] Figure 4 This is an exploded view of the structure of an axial flux permanent magnet motor.

[0022] Figure 5 This is a schematic diagram illustrating the heat dissipation principle of a heat spreader.

[0023] Figure 6 This is an axial cross-sectional view of the heat spreader.

[0024] Figure 7 This is a radial cross-sectional view of the heat exchanger.

[0025] Figure 8 This is a schematic diagram of the stator assembly.

[0026] Figure 9 A schematic diagram of the stator slot structure in the stator assembly.

[0027] Figure 10 This is a schematic diagram of the rotor assembly.

[0028] In the diagram: 1. Housing; 10. End cap; 11. Placement slot; 2. Rotor core; 20. Permanent magnet; 21. Shaft; 22. First bearing; 23. Second bearing; 3. Stator core; 30. Armature winding; 31. Stator core back yoke; 32. Stator slot; 4. Heat spreader; 40. Evaporation end; 41. Condensation end; 42. Steam chamber; 43. Liquid wick; 44. Capillary microchannel; 45. Steam passage; 5. Thermally conductive epoxy resin; 6. Air gap. Detailed Implementation

[0029] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. 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 should fall within the scope of protection of the present invention. Unless otherwise specified, the technical means used in the embodiments are conventional means well known to those skilled in the art.

[0030] like Figures 1 to 10 As shown, this embodiment of the invention provides an axial flux permanent magnet motor with high-efficiency heat dissipation based on a heat exchange plate. The permanent magnet motor includes: a housing 1 and a stator assembly, a rotor assembly, a bearing assembly, and a thermally conductive epoxy resin 5 disposed inside the housing 1. The stator assembly is disposed on the inner bottom surface of the housing 1, the rotor assembly is connected to the housing 1 through the bearing assembly, and the thermally conductive epoxy resin 5 is disposed between the inner side surface of the housing 1 and the stator assembly. A heat exchange plate 4 is also disposed inside the housing 1, and the heat exchange plate 4 is located between the inner bottom surface of the housing 1 and the stator assembly.

[0031] In this way, the stator assembly in the permanent magnet motor has a strong heat generation capacity. Therefore, a heat dissipation plate 4 is set between the inner bottom surface of the housing 1 and the stator assembly. The heat dissipation plate 4 utilizes the efficient two-dimensional planar thermal conductivity to dissipate heat from the back yoke 31 side of the stator core of the stator assembly. Thermally conductive epoxy resin 5 is used to pot the space between the stator assembly and the inner surface of the housing 1. The thermally conductive epoxy resin 5 is embedded in the space between the cavity of the stator assembly and the inner surface of the housing 1, so that heat can be conducted from the armature winding 30 to the housing 1 more quickly. Then, multiple ribs are set on the side of the rotor core 2 facing the stator assembly. When the motor rotates, the internal airflow is disturbed, the air circulation is enhanced, and the stator assembly is dissipated. Therefore, the stator assembly, which has a strong heat generation capacity in the motor, is dissipated in multiple ways, which greatly improves the heat dissipation efficiency of the stator assembly, thereby improving the overall heat dissipation efficiency of the motor.

[0032] like Figures 5 to 7As shown, the heat spreader 4 is annular and has a two-layer structure. The upper layer of the heat spreader 4 is the evaporation end 40, and the lower layer is the condensation end 41. The vapor chamber 42 formed by the docking of the evaporation end 40 and the condensation end 41 is used to store the liquid working fluid. Multiple liquid wicks 43 are provided between the evaporation end 40 and the condensation end 41. The multiple liquid wicks 43 are evenly distributed along the circumference of the heat spreader 4. Capillary microchannels 44 are provided in the vapor chamber 42. The capillary microchannels 44 are designed as a spider web biomimetic structure. The capillary microchannels 44 are distributed along the circumference of the condensation end 41 and radiate from the center of the evaporation end 40 to the edge. Vapor channels 45 are formed between the multiple liquid wicks 43. The vapor generated by the evaporation end 40 can diffuse to the condensation end 41 through the vapor channels 45 for condensation.

[0033] Specifically, the heat spreader 4 is generally made of copper, and its interior is a closed low-vacuum state. A vapor chamber 42, formed by the docking of the evaporation end 40 and the condensation end 41, is filled with a suitable liquid working fluid. This liquid working fluid has a low boiling point and is easily volatile. When the stator core 3 generates heat, it transfers the heat to the evaporation end 40 of the heat spreader 4. Within the low-vacuum chamber, the liquid working fluid boils and vaporizes. Under the pressure difference, the gas flows towards the condensation end 41, where it condenses and releases heat. The heat is then dissipated from the condensation end 41 of the heat spreader 4, while the condensed liquid, under the influence of gravity and the wicking core 4... Under the action of capillary force, the liquid working medium flows back to the evaporation end 40, and then continues to evaporate at the evaporation end 40. The evaporation process continuously removes heat from the stator core 3, and then diffuses through the steam channel 45 to the condensation end 41 for condensation again. This process is repeated, which can continuously transfer heat from the stator core 3, thereby achieving heat dissipation for the stator components with strong heat generation capacity in the motor. Furthermore, by setting multiple liquid suction cores 43, the liquid working medium condensed at the condensation end 41 is returned to the evaporation end 40, thereby accelerating the circulation process of the liquid working medium and thus accelerating the heat dissipation of the stator core 3 by the heat spreader 4.

[0034] In summary, as the liquid working fluid evaporates to the wick 43 portion of the condenser end 41, the gradual hydrophobicity around the wick 43 towards the central condensation zone accelerates the flow of vapor from the wick 43 portion towards the capillary channel 44. Due to the combined effect of gravity and capillary suction of the liquid working fluid, the vapor working fluid liquefies and flows through the wick 43 towards the evaporation end 40. As the gradual hydrophobicity around the wick 43 towards the boiling zone in the evaporation end 40 accelerates the flow of liquid working fluid through the microchannels of the wick 43 towards the boiling zone, the return path of the working fluid in the wick 43 is shortened, the return speed of the liquid working fluid is accelerated, and the heat dissipation efficiency is improved.

[0035] like Figures 5 to 7As shown, the liquid-absorbing core 43 has a porous structure and a honeycomb-like appearance; the liquid-absorbing core 43 is located at the connection of adjacent capillary microchannels 44.

[0036] like Figure 5 As shown, by utilizing the capillary force of the liquid suction core 43, capillary microchannels 44 are provided on the condensing end 41, and the liquid suction core 43 is located at the connection of adjacent capillary microchannels 44, thereby accelerating the rapid return of the liquid working fluid in the liquid suction core of the condensing end 41 to the evaporating end 40, thereby accelerating the heat dissipation process of the heat spreader 4 and improving the heat dissipation efficiency of the motor.

[0037] like Figure 3 As shown, a placement groove 11 is formed on the inner bottom surface of the housing 1, and the placement groove 11 is filled with an interfacial thermally conductive material. The heat spreader 4 is placed in the placement groove 11, and the evaporation end 40 of the heat spreader 4 is glued to the stator assembly, while the condensation end 41 of the heat spreader 4 abuts against the interfacial thermally conductive material in the placement groove 11. In this way, the interfacial thermally conductive material is filled in the gap between the placement groove 11 and the heat spreader 4, which increases and fixes the effective contact area between the heat spreader 4 and the housing 1, thereby improving the heat dissipation effect of the condensation end 41.

[0038] like Figures 8 to 9 As shown, the stator assembly includes a stator core 3 and an armature winding 30. The stator core 3 is annular. The stator core back yoke 31 of the stator core 3 is bonded to the inner bottom surface of the housing 1 and the evaporation end 40 of the heat spreader 4. The stator core 3 has multiple stator slots 32 evenly opened along its circumference and the armature winding 30 is embedded in the stator slots 32.

[0039] like Figure 8 and Figure 9 As shown, the stator core 3 is designed in a ring shape to meet the compact and flat shape requirements of the axial flux permanent magnet motor. The stator core back yoke 31 is bonded to the inner bottom surface of the housing 1 and the evaporation end 40, and directly contacts the evaporation end 40 of the heat spreader 4. This arrangement allows the stator core 3 to quickly transfer heat to the heat spreader 4, and the heat spreader 4 can quickly dissipate heat to the environment through its efficient two-dimensional thermal conductivity. In addition, multiple stator slots 32 are arranged radially around the inner circumference of the stator core 3. The armature winding 30 is arranged in a double-layer winding distributed on the left and right sides in the stator slots 32. This not only increases the effective number of turns of the winding, but also optimizes the current path, reduces resistance loss, and improves the power output capability and efficiency of the motor.

[0040] like Figure 3 As shown, an end cover 10 is provided on the housing 1, and the end cover 10 is detachably connected to the housing 1 by fixing screws. This facilitates the assembly and maintenance of the components inside the housing 1.

[0041] like Figure 3The bearing assembly includes: a first bearing chamber, a first bearing 22, a second bearing chamber, and a second bearing 23. The first bearing chamber is located on the end cover 10; the first bearing is housed within the first bearing chamber; the second bearing chamber is located on the housing 1; and the second bearing 23 is housed within the second bearing chamber. Thus, two bearing chambers are provided to provide stable support for the two bearings.

[0042] like Figure 3 He Ru Figure 10 As shown, the rotor assembly includes: a rotating shaft 21, a rotor core 2, and permanent magnets 20. The rotating shaft 21 is connected to the housing 1 through a first bearing 22 and a second bearing 23. The rotor core 2 is fixedly connected to the rotating shaft 21. Multiple permanent magnets 20 are attached to the rotor core 2, and the permanent magnets 20 are located between the rotor core 2 and the stator core 3. There is an air gap 6 between the stator core 3 and the permanent magnets 20. In this way, the rotating shaft 21 is stably connected to the housing 1 and the end cover 10 through two bearings, thereby achieving stable rotation. The rotor core 2 is set in a ring shape and fixedly sleeved on the rotating shaft 21. A permanent magnet 20 is attached to the side of the rotor core 2 near the stator core 3. When current passes through the armature winding 30 on the stator core 3, a rotating magnetic field is generated. This rotating magnetic field interacts with the permanent magnet 20 attached to the rotor core 2. Under the action of the rotating magnetic field, the permanent magnet 20 is driven by torque, causing the rotor core 2 to start rotating. The rotor core 2 is fixedly connected to the rotating shaft 21, so the rotation of the rotor core 2 will drive the rotating shaft 21 to rotate together. In addition, the air gap 6 between the stator core 3 and the permanent magnet 20 allows the magnetic field generated by the stator to interact with the permanent magnet 20 on the rotor, thereby driving the rotor to rotate. On the other hand, it provides space for natural convection inside the motor, which helps heat dissipation and reduces the risk of performance degradation or damage caused by overheating.

[0043] Furthermore, the rotor core 2 has multiple ribs on one side of the permanent magnet 20. In this way, the ribs on the surface of the rotor core 2 disturb the internal airflow when the motor rotates, thereby enhancing air cooling and heat dissipation.

[0044] Implementation Process: During use, the armature winding 30 is energized. When current flows through the armature winding 30 on the stator core 3, a rotating magnetic field is generated. This rotating magnetic field interacts with the permanent magnet 20 attached to the rotor core 2. Under the action of the rotating magnetic field, the permanent magnet 20 is driven by torque, causing the rotor core 2 to start rotating. The rotor core 2 is fixedly sleeved on the shaft 21, so the rotation of the rotor core 2 will drive the shaft 21 to rotate as well. When the armature winding 30 is energized, heat is generated. A heat spreader 4 is set between the stator core back yoke 31 and the housing 1. Utilizing the efficient two-dimensional planar thermal conductivity of the heat spreader 4, a heat exchange path is set between the stator core 3 and the external environment. The armature winding 30 is in direct contact with the stator core 3, and the heat generated by the armature winding 30 can be... The heat is transferred to the stator core 3 through the contact part, and then transferred to the outside of the motor by the heat dissipation plate 4 set on the stator core 3, which accelerates the heat dissipation of the armature winding 30. At the same time, the cavity between the stator core 3 and the inner side of the housing 1 is filled with thermally conductive epoxy resin 5, which shortens the heat transfer path and conducts the residual heat generated by the armature winding 30 away through the housing 1. In addition, the rotor core 2 has multiple ribs on the side where the permanent magnet 20 is set. In this way, the internal airflow is disturbed when the motor rotates, which enhances the air cooling heat dissipation. Therefore, the stator core 3 in the motor forms multiple heat dissipation paths, which greatly improves the heat dissipation efficiency of the stator assembly, thereby improving the overall heat dissipation efficiency of the motor. This keeps the inside of the motor in a relatively low temperature environment, thereby improving the service life of the motor.

[0045] It should be noted that the specific models and specifications of the permanent magnet 20, the first bearing 22, and the second bearing 23 need to be selected and determined according to the actual specifications of the device, and therefore will not be described in detail.

[0046] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention can have various modifications and variations. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. An axial flux permanent magnet motor based on high efficiency heat dissipation of a uniform heat plate, comprising: The housing (1) and the stator assembly, the rotor assembly, the bearing assembly and the heat-conducting epoxy resin (5) arranged inside the housing (1), the stator assembly is arranged on the inner bottom surface of the housing (1), the rotor assembly is connected with the housing (1) through the bearing assembly, and the heat-conducting epoxy resin (5) is arranged between the inner side surface of the housing (1) and the stator assembly, characterized in that the housing (1) is further provided with a heat plate (4), and the heat plate (4) is located between the inner bottom surface of the housing (1) and the stator assembly. The heat plate (4) is a circular ring type, and the heat plate (4) has a two-layer structure, the upper layer of the heat plate (4) is an evaporation end (40), the lower layer of the heat plate (4) is a condensation end (41), a steam cavity (42) is formed by the butt joint of the evaporation end (40) and the condensation end (41), and the steam cavity (42) is used for storing a liquid working medium; a plurality of wick cores (43) are arranged between the evaporation end (40) and the condensation end (41), the plurality of wick cores (43) are uniformly distributed along the circumferential direction of the heat plate (4), a capillary micro channel (44) is arranged in the steam cavity (42), the capillary micro channel (44) is arranged in a spider web bionic structure, the capillary micro channel (44) is distributed in the circumferential direction of the condensation end (41), the capillary micro channel (44) diverges from the center of the evaporation end (40) to the edge, and the plurality of wick cores (43) form a steam passage (45).

2. The axial flux permanent magnet motor based on the heat plate high-efficiency heat dissipation according to claim 1, characterized in that, The wick core (43) is a porous structure, and the appearance of the wick core (43) is honeycomb-shaped; The wick core (43) is arranged at the connection position of adjacent capillary micro channels (44).

3. The axial flux permanent magnet motor with high efficiency heat dissipation based on the uniform heat plate, according to claim 1, characterized in that, A placing groove (11) is formed in the inner bottom surface of the housing (1), and an interface heat-conducting material is filled in the placing groove (11); the heat plate (4) is arranged in the placing groove (11), the evaporation end (40) of the heat plate (4) is glued to the stator assembly, and the condensation end (41) of the heat plate (4) abuts against the interface heat-conducting material in the placing groove (11).

4. The axial flux permanent magnet motor with high efficiency heat dissipation based on the uniform heat plate according to claim 1, characterized in that, The stator assembly comprises: A stator core (3), the stator core (3) is a circular ring type, a stator core back yoke (31) of the stator core (3) is bonded to the inner bottom surface of the housing (1) and the evaporation end (40) of the heat plate (4), and a plurality of stator slots (32) are uniformly formed in the circumferential direction of the stator core (3); An armature winding (30) is embedded in the stator slot (32).

5. The axial flux permanent magnet motor with high efficiency heat dissipation based on the uniform heat plate, according to claim 1, characterized in that, An end cover (10) is arranged on the housing (1), and the end cover (10) is detachably connected with the housing (1) through a fixing screw.

6. The axial flux permanent magnet motor with high efficiency heat dissipation based on the uniform heat plate, according to claim 5, characterized in that, The bearing assembly comprises: A first bearing chamber is formed in the end cover (10); A first bearing (22) is arranged in the first bearing chamber; A second bearing chamber is formed in the housing (1); A second bearing (23) is arranged in the second bearing chamber.

7. The axial flux permanent magnet motor with high efficiency heat dissipation based on the uniform heat plate, according to claim 5, characterized in that, The rotor assembly comprises: A rotating shaft (21) is connected with the housing (1) through the first bearing (22) and the second bearing (23). A rotor iron core (2) is fixedly connected to a rotating shaft (21); A plurality of permanent magnets (20) are attached to the rotor iron core (2), and the permanent magnets (20) are located between the rotor iron core (2) and a stator iron core (3), and an air gap (6) is formed between the stator iron core (3) and the permanent magnets (20).

8. The axial flux permanent magnet motor with high efficiency heat dissipation based on the uniform heat plate, according to claim 7, characterized in that, The rotor iron core (2) is provided with a plurality of rib plates on the side provided with the permanent magnets (20).

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