Axial flux motor

Abstract

The utility model provides a kind of axial flux motor, comprising: motor shell (1);Motor shaft (2);Stator (3);First rotor (4a) and second rotor (4b), they are symmetrically arranged in the direction of the motor shaft at the two sides of stator and fixedly connected to motor shaft;Wherein first rotor and second rotor all include rotor disc (4), it has disc-shaped main body (40) and center hole (41), the disc-shaped main body has first surface (40a) facing motor shell and second surface (40b) facing stator;Wherein disc-shaped main body is additionally provided with multiple airflow passages (5) arranged around center hole, each airflow passage has first port (51) in first surface (40a) and second port (52) in second surface (40b), wherein airflow passage is arranged to be inclined from first surface towards second surface, and second port is closer to center hole than first port.

Description

Technical Field

[0001] This utility model relates to the field of motor technology, and in particular to an axial flux motor with an improved heat dissipation design. Background Technology

[0002] Axial flux forced air-cooled motors are widely used in new energy vehicles, industrial drives, and wind power generation due to their compact structure and high power density. With the continuous increase in motor power density, the heat generated during operation increases significantly. If heat dissipation is not timely, it will seriously affect the motor's operational stability and service life. Therefore, improving the heat dissipation capacity of axial flux motors has become a key research focus in this field.

[0003] Existing forced air cooling for axial flux motors mostly relies on air guide plates or fan mechanisms. Although this can improve heat dissipation, it requires additional components, which complicates the process and increases the material and processing costs of the motor assembly.

[0004] Existing technologies have proposed various improvement schemes, such as: improving heat dissipation on the back of the rotor core by setting a guide plate and radial air ducts on the back of the rotor disk; increasing the stator heat dissipation area by setting a uniformly distributed permeable microporous structure on the motor base; enhancing the air intake by setting an airflow drive component on the rotor assembly to form a radial air intake and exhaust structure; and achieving external air circulation cooling by driving a fan mechanism through the interaction between the magnet and the stator mechanism.

[0005] While the aforementioned technologies have made some progress in heat dissipation for axial flux motors, problems remain, such as locally limited heat dissipation paths, uneven airflow distribution, or complex structures that hinder manufacturing and maintenance. Therefore, there is a current need for an axial flux motor with a more rational structure, superior cooling performance, and ease of implementation to meet the ever-increasing demands for heat dissipation performance in high-performance motors. Utility Model Content

[0006] In order to overcome at least one of the above problems, the purpose of this utility model is to provide an axial flux motor with an improved heat dissipation design.

[0007] Therefore, this utility model provides an axial flux motor, comprising: a motor housing; a motor shaft; a stator fixedly mounted to the motor housing; a first rotor and a second rotor, which are symmetrically arranged on both sides of the stator along the direction of the motor shaft and fixedly connected to the motor shaft; wherein both the first rotor and the second rotor include a rotor disk, wherein the rotor disk has a disc-shaped body and a central hole, the disc-shaped body having a first surface facing the motor housing and a second surface facing the stator; wherein the disc-shaped body is further provided with a plurality of airflow channels arranged around the central hole, each airflow channel having a first port located in the first surface and a second port located in the second surface, wherein the airflow channels are arranged to be inclined from the first surface toward the second surface, and the first port is closer to the central hole in the radial direction than the second port.

[0008] In the above-mentioned technical solution of this utility model, by setting an inclined air passage in the rotor, it is helpful for air or cooling medium to flow axially and radially when the rotor rotates, so that the airflow blows towards the stator, which is beneficial to accelerate heat dissipation and further relieve the heat dissipation pressure of the stator.

[0009] According to a preferred embodiment of this invention, the angle between the central axis of the airflow channel and the radial direction of the disc-shaped body is 30° to 60°. If the angle is too small, for example less than 30°, it is not conducive to processing and forming; if the angle is too large, for example greater than 60°, it is not conducive to heat dissipation.

[0010] According to a preferred embodiment of the present invention, the outer periphery of the disc-shaped body of the rotor is provided with a flow guiding structure to guide airflow during the rotation of the first rotor and the second rotor, thereby enhancing the heat dissipation efficiency of the rotor disc.

[0011] In a preferred embodiment, the airflow guiding structure is configured to include a plurality of circumferentially evenly arranged tooth-like portions along the outer periphery. These tooth-like portions form a fan-like tooth structure, further enhancing airflow guidance.

[0012] In a preferred embodiment, the airflow channel is configured such that its cross-section gradually narrows from the first port toward the second port along the thickness direction of the disk-shaped body, thus forming an airflow channel that is wider at the front and narrower at the back. This front-wide and rear-narrow channel is similar to the Venturi effect, where the airflow accelerates from the large cross-section to the small cross-section, increasing the airflow velocity inside the rotor disk, which is beneficial for heat removal. Furthermore, combined with the symmetrical design of the dual rotors, it reduces the mechanical stress caused by axial force imbalance.

[0013] According to one embodiment of this invention, the first rotor and the second rotor each further include a back iron and a permanent magnet. An annular groove suitable for receiving the back iron and the permanent magnet is provided on the second surface of the disc-shaped main body. This annular groove is located radially outside the airflow channel. For an axial flux motor, the heat source is mainly divided into three parts: stator coil heating; rotor magnet (permanent magnet) heating; and rotor back iron heating. The airflow channel is located radially inside the back iron and the permanent magnet, which does not affect the magnetic flux, enabling more effective heat dissipation, reducing performance degradation caused by permanent magnet demagnetization or overheating, and extending the motor's lifespan.

[0014] According to a preferred embodiment of this utility model, the motor housing includes a first housing component and a second housing component. Multiple heat dissipation fins are provided on the inner and outer sidewalls of both the first and second housing components, and these fins are arranged radially. By providing heat dissipation fins, not only can the mechanical strength of the motor housing be increased, but the heat dissipation area of ​​the motor housing can also be increased. Furthermore, this radial heat dissipation fin design facilitates air convection, reducing the housing thickness and weight while ensuring heat dissipation.

[0015] Advantageously, the size and arrangement density of the multiple heat dissipation fins are selected such that the total heat dissipation area of ​​the motor housing is increased by at least 0.5 times compared to a motor housing without heat dissipation fins.

[0016] According to one aspect of this utility model, the stator is an annular printed circuit board stator (PCB stator), with the annular edge of the stator sandwiched between a first housing component and a second housing component. The stator includes: a plurality of stator coils equidistantly arranged along its thickness direction; a plurality of strip-shaped copper layers arranged radially along its radial direction; and a plurality of metallized vias penetrating the thickness of the stator. In the above stator, the stator coils are the main heat source of the PCB stator. The radially arranged copper layers inside the stator and the metallized vias penetrating the entire thickness of the PCB stator can effectively conduct the heat generated on the stator coils to the motor housing, where the heat is transferred to the air through the heat dissipation fins. Furthermore, the heat inside the PCB stator is conducted to the stator surface through the metallized vias, and the surface heat is dissipated by the internal circulating air, ultimately being dissipated through heat exchange between the air and the motor housing.

[0017] In a preferred embodiment, the annular edge has a contact surface that directly contacts the first housing component and the second housing component, and the contact surface is coated with a copper layer. This copper layer increases thermal conductivity, ensuring good heat conduction between the stator and the motor housing.

[0018] In a preferred embodiment of this invention, the heat-conducting medium inside the motor housing is helium. Compared with air as the heat-conducting medium, helium has high thermal conductivity and low density, which is beneficial for accelerating the transfer of heat from the heat-generating components (stator coils, permanent magnets, rotor discs) to the motor housing, significantly improving heat dissipation efficiency.

[0019] By adopting the above technical solutions, the axial flux motor with improved heat dissipation design of this utility model can produce at least one of the following beneficial technical effects: active heat dissipation, improving heat dissipation efficiency; increasing the strength of the motor housing by adding heat dissipation fins, which can further reduce the housing thickness, thereby reducing weight and cost; designing inclined airflow channels in the rotor disk to blow towards the stator, further relieving the heat dissipation pressure on the stator; and using helium gas with higher thermal conductivity to replace air as the internal heat transfer medium of the motor, greatly improving heat dissipation efficiency. This utility model is mainly used in scenarios where axial space and weight are relatively sensitive, such as automotive braking systems, drones, and robot joints. This axial flux motor achieves cooling through the structural design of the rotor and stator, thereby maximizing energy utilization and ultimately achieving a significant increase in power density. Attached Figure Description

[0020] Referring to the accompanying drawings and reading the following detailed description, further features and advantages of this utility model will become clearer:

[0021] Figure 1 An embodiment of an axial flux motor according to the present invention is shown;

[0022] Figure 2 for Figure 1 An exploded view of the axial flux motor shown.

[0023] Figure 3 for Figure 1 The axial cross-sectional view of the axial flux motor shown.

[0024] Figure 4 This is an exploded view of one embodiment of the rotor according to the present invention;

[0025] Figure 5 for Figure 1 The partial axial cross-sectional view of the axial flux motor shown illustrates the direction of airflow within the motor during rotor rotation.

[0026] Figure 6 for Figure 1 The partial axial cross-sectional view of the axial flux motor shown illustrates the angle between the airflow passage and the radial direction of the rotor's disc-shaped body; and

[0027] Figure 7 It shows Figure 1The diagram shows the heat dissipation paths of the stator and rotor of an axial flux motor. Detailed Implementation

[0028] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. The descriptions of orientations used in the following description, such as "upper," "lower," "inner," and "outer," are for convenience only unless explicitly stated otherwise and are not intended to limit the technical solution of the present invention. Furthermore, terms such as "first" and "second" are used below to describe elements of this application; these terms are only used to distinguish individual elements and are not intended to limit the nature, sequence, order, or number of these elements. Additionally, it should be noted that in this specification, the same technical features are represented by the same or similar reference numerals.

[0029] Figure 1 An embodiment of the axial flux motor 100 according to the present invention is shown. Figure 2 for Figure 1 An exploded view of the axial flux motor. As shown in the figure, the axial flux motor 100 is a dual-rotor motor, including a motor housing 1, a motor shaft 2, a stator 3, a first rotor 4a, and a second rotor 4b. The first rotor 4a and the second rotor 4b have identical structures and are symmetrically arranged on both sides of the stator 3 along the direction of the motor shaft 2, and are fixedly connected to the motor shaft 2, so that the motor shaft 2 can drive the two rotors to rotate together during motor operation. In this embodiment, the motor housing 1 adopts a two-component structure, including a first housing component 11 and a second housing component 12.

[0030] In this embodiment of the axial flux motor 10, the stator 3 is fixedly mounted to the motor housing 1, and the stator is an annular printed circuit board stator, also known as a PCB stator. Compared to traditional stators composed of laminated silicon steel sheets and winding coils, the PCB stator uses a multi-layer printed circuit board as its substrate material. The stator coil size and arrangement height are consistent, resulting in extremely high winding geometric accuracy and reducing losses caused by asymmetry between windings. The annular edge 30 of the stator 3 is clamped between the first housing component 11 and the second housing component 12, thereby ensuring its assembly stability. See also... Figure 7 The stator 3 internally includes multiple stator coils 31 equidistantly arranged along the thickness direction, multiple strip-shaped copper layers 32 arranged radially, and multiple metallized vias 33 penetrating the thickness direction of the stator to ensure uniform current conduction and efficient motor operation. Preferably, the contact surface of the annular edge 30 of the stator 3 is coated with a copper layer, especially completely coated with a copper layer, to enhance the thermal conductivity between the stator and the housing, thereby facilitating the conduction and dissipation of the stator's operating heat to the motor housing. Here, "annular edge" refers to the outermost edge of the annular stator, which is an annular "strip" area near the outer diameter.

[0031] See Figure 4 An exploded view of the rotor is shown. As can be seen from the figure, both the first rotor 4a and the second rotor 4b include a rotor disk 4, a back iron 7, and a permanent magnet 8. The rotor disk 4 has a disc-shaped body 40 and a central hole 41. The first and second rotors are fixedly mounted to the motor shaft 2 via the central hole 41 (e.g., via an interference fit). The disc-shaped body 40 has a first surface 40a and an opposite second surface 40b. In the assembled state, the first surface 40a faces the motor housing 1, and the second surface 40b faces the stator 3. Advantageously, a plurality of airflow channels 5 are arranged around the central hole 41 in the disc-shaped body 40. Each airflow channel 5 has a first port 51 located in the first surface 40a and a second port 52 located in the second surface 40b. The airflow channels 5 are arranged to be inclined from the first surface 40a toward the second surface 40b, and the first port 51 is radially closer to the central hole 41 than the second port 52, thereby creating a favorable air guiding effect during rotor rotation.

[0032] See Figure 6 In a preferred embodiment, the angle α (i.e., the tilt angle) between the airflow channel 5 and the radial direction of the disc-shaped body is 30° to 60°. If the tilt angle is too small, it will be detrimental to the processing and shaping of the airflow channel 5. Furthermore, the tilt angle α is also important for heat dissipation efficiency. If the tilt angle is too large, it will cause airflow backflow, which is not conducive to heat dissipation. As shown in the figure, during operation, the airflow enters along the tilted yellow arrow. The purpose of setting the tilted airflow channel is to maximize the upward flow of the incoming airflow along the upward red arrow in the figure, flowing over the stator and rotor surfaces to achieve the cooling effect. If the tilt angle (angle α) is too large, it will cause some airflow to flow towards the motor shaft along the downward purple arrow in the figure, causing airflow blockage and reducing heat dissipation efficiency.

[0033] In a preferred embodiment, the airflow channel 5 is configured such that the cross-section gradually narrows from the first port 51 toward the second port 52 along the thickness direction of the disc-shaped body 40, forming a structure that is wider at the front and narrower at the back. This tapering design helps to form an accelerated airflow inside the channel, thereby improving heat dissipation efficiency.

[0034] exist Figure 4 In the illustrated embodiment, an annular groove 40c is provided in the second surface 40b of the disc-shaped body 40, and the annular groove is located radially outward of the airflow channel 5. The annular groove 40c is used to accommodate the back iron 7 and the permanent magnet 8. The back iron 7 is located between the inner side of the disc-shaped body and the permanent magnet, thereby forming a complete magnetic circuit structure to ensure the electromagnetic performance and power output of the motor.

[0035] In a preferred embodiment, a flow guiding structure 6 is also provided at the outer periphery 42 of the disc-shaped body 40 to force airflow during rotor rotation, further improving the heat dissipation effect inside the motor. In particular, the flow guiding structure 6 includes a plurality of toothed portions 60 evenly arranged circumferentially along the outer periphery 42. These toothed portions can enhance the generation of turbulent airflow like fan blades during rotor rotation, promoting the convection dissipation of internal heat.

[0036] To further improve heat dissipation performance, multiple heat dissipation fins 9 are provided on the inner and outer sidewalls of both the first housing component 11 and the second housing component 12. These heat dissipation fins are radially distributed. This arrangement of heat dissipation fins not only increases the mechanical strength of the motor housing but also increases its heat dissipation area. Furthermore, this radial heat dissipation fin design facilitates air convection, reducing housing thickness and weight while ensuring heat dissipation. Preferably, the size and arrangement density of the heat dissipation fins 9 are selected such that the total heat dissipation area of ​​the motor housing 1 is increased by at least 0.5 times compared to a motor housing without heat dissipation fins, i.e., 1.5 times the total heat dissipation area of ​​a motor housing without heat dissipation fins, thereby significantly improving the heat dissipation capacity of the motor housing.

[0037] Preferably, helium gas can be filled inside the motor housing 1 as a heat-conducting medium. Helium gas has a higher thermal conductivity and lower density than air, which can accelerate the transfer of heat from inside the motor to the housing and reduce gas resistance, thereby achieving a more efficient heat dissipation effect. This design ensures the stability and reliability of the motor under high power density and long-term operating conditions.

[0038] The following is for reference Figure 5 and Figure 7 The following describes the heat dissipation path of the axial flux motor 100 according to the present invention. For an axial flux motor, the heat source of the motor is mainly divided into three parts: stator coil heating; rotor magnet (permanent magnet) heating; and rotor back iron heating.

[0039] Figure 5 The diagram illustrates that during the rotation of the first rotor 4a and the second rotor 4b, an internal heat-conducting medium, such as air or helium, flows between the rotors 4a and 4b and the stator 3, and between the rotors 4a and 4b and the inner wall of the motor housing 1. The flow direction is shown by the arrow in the figure. Heat dissipation is mainly achieved through heat exchange between the rotor disk and the internal circulating heat-conducting medium, followed by heat exchange between the heat-conducting medium and the motor housing, and finally, the heat is conducted to the outside air through the motor housing.

[0040] To improve heat dissipation efficiency, the rotor disk 4 and motor housing 1 of the axial flux motor are improved with the heat dissipation design as described above. Multiple toothed portions 60 are provided at the outer periphery 42 of the disc-shaped body 40, forming a fan-like toothed structure that guides airflow during rotor rotation. Furthermore, inclined airflow channels 5 are provided in the disc-shaped body 40 of the rotor disk, especially those wider at the front and narrower at the rear, which helps to guide airflow and direct it towards the stator, accelerating heat dissipation. These structural improvements to the rotor increase the flow velocity of the heat-conducting medium, thereby increasing heat exchange efficiency. In addition, by arranging radially arranged heat dissipation fins on both the inner and outer sides of the motor housing, not only is the structural strength of the housing enhanced, but the heat exchange area between the internal hot air and the housing is also significantly increased, improving heat dissipation efficiency. Furthermore, the axial flux motor of this invention also improves the heat-conducting medium. Conventional air has a low thermal conductivity; to improve heat conduction efficiency, helium can be used instead of air. Helium's thermal conductivity is approximately six times that of air, significantly enhancing the overall heat dissipation performance of the motor.

[0041] See Figure 7 The stator 3 primarily generates heat through the stator coils 31. A radially radiating strip of copper is arranged inside the PCB stator, allowing heat generated by the stator coils to be transferred radially to the stator's radial edge. Multiple metallized vias along the stator's thickness rapidly transfer heat from the stator coils to the PCB stator surface along the stator's axial direction. Heat from the stator surface is carried away by an internal circulating heat transfer medium, and then conducted to the motor housing via heat exchange with the motor housing. Furthermore, an additional copper layer is coated on the contact surface of the annular edge 30 of the stator 3, which contacts the first housing component 11 and the second housing component 12. This allows the heat conducted through the strip copper layer and metallized vias to be ultimately transferred to the motor housing. The motor housing then undergoes convective heat exchange with the external air through externally arranged heat dissipation fins, achieving efficient heat dissipation.

[0042] The axial flux motor 100 provided by this utility model significantly improves the heat dissipation performance and power density of the motor by setting an inclined and gradually narrowing airflow channel and an outer peripheral flow guiding structure on the rotor disk, combined with PCB stator design, heat dissipation fin structure and helium heat conduction medium, and reduces the risk of thermal failure, thereby achieving efficient, stable and long-life operation of the axial flux motor.

[0043] Although the present invention has been disclosed above with reference to preferred embodiments, it is not limited thereto. Any combinations, changes, and modifications made by those skilled in the art without departing from the spirit and scope of the present invention should be included within the protection scope of the present invention. Therefore, the protection scope of the present invention should be determined by the scope defined in the claims.

Claims

1. An axial flux motor, characterized in that, The axial flux motor (100) includes: Motor housing (1); Motor shaft (2); Stator (3), the stator is fixedly installed to the motor housing (1); The first rotor (4a) and the second rotor (4b) are arranged symmetrically on both sides of the stator along the direction of the motor shaft and are fixedly connected to the motor shaft (2). Both the first rotor and the second rotor include a rotor disk (4), wherein the rotor disk has a disc-shaped body (40) and a central hole (41), and the disc-shaped body (40) has a first surface (40a) facing the motor housing (1) and a second surface (40b) facing the stator (3); The disc-shaped body is further provided with a plurality of airflow channels (5) arranged around the central hole (41), each airflow channel (5) having a first port (51) located in the first surface (40a) and a second port (52) located in the second surface (40b), wherein the airflow channel is arranged to be inclined from the first surface toward the second surface, and the second port (52) is closer to the central hole in the radial direction than the first port (51).

2. The axial flux motor according to claim 1, characterized in that, The angle between the central axis of the airflow channel and the radial direction of the disc-shaped body is 30° to 60°.

3. The axial flux motor according to claim 1 or 2, characterized in that, The outer periphery (42) of the disc-shaped body (40) of the rotor is provided with a flow guiding structure (6) for forcing airflow during the rotation of the first rotor and the second rotor.

4. The axial flux motor according to claim 3, characterized in that, The flow guiding structure (6) includes a plurality of tooth-shaped portions (60) evenly arranged circumferentially along the outer periphery.

5. The axial flux motor according to claim 1 or 2, characterized in that, The cross-section of the airflow channel (5) gradually narrows from the first port (51) toward the second port (52) along the thickness direction of the disc-shaped body.

6. The axial flux motor according to claim 1 or 2, characterized in that, The first rotor and the second rotor each further include a back iron (7) and a permanent magnet (8). The second surface of the disc-shaped body is provided with an annular groove (40c) suitable for receiving the back iron (7) and the permanent magnet (8). The annular groove is located on the radial outer side of the airflow channel (5).

7. The axial flux motor according to claim 1 or 2, characterized in that, The motor housing (1) includes a first housing component (11) and a second housing component (12). The inner and outer sidewalls of the first housing component (11) and the second housing component (12) are provided with a plurality of heat dissipation fins (9), which are arranged radially in the radial direction.

8. The axial flux motor according to claim 7, characterized in that, The size and arrangement density of the heat dissipation fins (9) are selected such that the total heat dissipation area of ​​the motor housing (1) is increased by at least 0.5 times compared with a motor housing without heat dissipation fins.

9. The axial flux motor according to claim 7, characterized in that, The stator (3) is an annular printed circuit board stator, and the annular edge (30) of the stator is sandwiched between the first housing component (11) and the second housing component (12); and The stator (3) includes: Multiple stator coils (31) are arranged at equal intervals along their thickness direction; Multiple strip-shaped copper layers (32) arranged radially along their radial direction; and Multiple metallized vias (33) extending through the thickness of the stator.

10. The axial flux motor according to claim 9, characterized in that, The annular edge (30) has a contact surface that directly contacts the first housing component (11) and the second housing component (12), and the contact surface is coated with a copper layer.

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