Motor heat dissipation structure with pressurized flow channel, outer rotor motor and heat dissipation method

Abstract

The application belongs to the technical field of electric machines, and particularly relates to a motor heat dissipation structure with a pressurized flow channel, an outer rotor motor and a heat dissipation method. The motor heat dissipation structure comprises a heat dissipation cover body, the lower surface of the heat dissipation cover body is provided with a plurality of heat dissipation blades extending radially from the center to the periphery, adjacent heat dissipation blades and the top surface of the heat dissipation cover body form heat dissipation flow channels for air flow, the axial height of the heat dissipation blades gradually decreases from inside to outside along the radial direction, so that the effective flow area of the heat dissipation flow channels gradually decreases in the air flow direction, the available air volume gradually decreases in the air flow direction, the variable cross-section flow channel design increases the air pressure and the air flow rate, and effectively improves the heat dissipation effect.

Description

[Technical Field] This application belongs to the field of motor technology, specifically relating to a motor heat dissipation structure with a booster flow channel, an external rotor motor, and a heat dissipation method. [Background Technology] Currently, drones and other devices widely use external rotor motors as their power source. These motors generate a significant amount of heat during high-speed operation. If this heat is not dissipated promptly, it will not only limit the motor's output power but also increase the risk of burnout. Most existing drone motor cooling structures employ straight fan blades. This structure generates outward airflow during high-speed motor rotation, carrying away internal heat to achieve a cooling effect. However, the motor's structure results in a smaller surface area closer to the shaft, and the airflow channel formed by the straight fan blades is also narrower on the inside and wider on the outside. As the airflow moves from the inside out—from the smaller channel to the larger one—the available air volume gradually increases, leading to a decrease in airflow velocity. Consequently, the cooling effect is actually weakened in the outermost areas that most require cooling. [Summary of the Invention] The purpose of this invention is to overcome the shortcomings of the prior art and provide a motor heat dissipation structure, motor, and heat dissipation method that improves heat dissipation by increasing air pressure.

[0004] This application is achieved through the following technical solution: A motor heat dissipation structure with a booster flow channel includes a heat dissipation cover body. The lower surface of the heat dissipation cover body is provided with a plurality of heat dissipation blades that radiate outward from the center. Adjacent heat dissipation blades and the top surface of the heat dissipation cover body form a heat dissipation flow channel for airflow. The axial height of the heat dissipation blades decreases radially from the inside to the outside, so that the effective flow cross-sectional area of ​​the heat dissipation flow channel gradually decreases in the direction of airflow.

[0005] As described above, the motor heat dissipation structure with a pressurized flow channel includes a first blade portion and a second blade portion arranged from the inside out, with a transition slope provided between the first blade portion and the second blade portion.

[0006] As described above, in the motor heat dissipation structure with a booster flow channel, the edge of the heat dissipation cover body is provided with a reinforcing rib that connects to the heat dissipation blades. The reinforcing rib is connected to the end of the heat dissipation blades, and the reinforcing rib, together with the two adjacent heat dissipation blades and the edge of the heat dissipation cover body, forms an independent airflow outlet.

[0007] As described above, in the motor heat dissipation structure with a booster flow channel, the heat dissipation cover body, the heat dissipation blades, and the reinforcing ribs are integrally formed.

[0008] An external rotor motor includes a stator assembly, a rotor assembly rotatably sleeved outside the stator assembly, and a motor heat dissipation structure with a booster flow channel as described in any of the preceding claims, wherein the heat dissipation cover body is fixedly mounted on the top end face of the rotor assembly.

[0009] As described above, in the external rotor motor, the rotor assembly includes a rotor housing, which includes a central housing, an outer peripheral housing, and multiple connecting arms connecting the central housing and the outer peripheral housing. An air intake area with a heat dissipation channel is formed between the central housing and the outer peripheral housing.

[0010] As described above, in the external rotor motor, the heat sink cover body is provided with a first connection hole, and the connecting arm is provided with a second connection hole. Fasteners pass through the first connection hole and the second connection hole to fix the heat sink cover body on the connecting arm.

[0011] As described above, in the external rotor motor, the stator assembly has an airflow inlet at its bottom and a through-flow air intake channel on its stator assembly. External airflow passes sequentially through the airflow inlet, the air intake channel, the air intake area, the heat dissipation channel, and the airflow outlet.

[0012] A heat dissipation method based on the external rotor motor described above includes the following steps: Step S1: The motor rotates, causing the heat sink cover to rotate synchronously. Under the action of centrifugal negative pressure, airflow is drawn in from the bottom of the motor and passes through the air intake channel of the stator assembly; Step S2: The airflow passes through the air intake area at the top of the rotor assembly and enters the heat dissipation channel below the heat sink cover; Step S3: Under the action of centrifugal force, the airflow flows radially towards the heat dissipation blades whose height gradually decreases, continuously compressing the effective cross-sectional area of ​​the channel and keeping the airflow in a high-pressure state; Step S4: When the high-pressure airflow reaches the edge of the heat sink cover, it is enclosed by reinforcing ribs to form an independent airflow outlet for secondary rectification and acceleration, and finally sprayed outwards at a high velocity to remove heat.

[0013] Compared with the prior art, this application has the following advantages: 1. This invention compensates for the small air volume near the center by raising the heat dissipation blades near the center, thereby increasing the initial usable air volume. At the same time, the height of the fan blades far from the center is lowered, so that the usable air volume gradually decreases in the direction of airflow. This variable cross-section flow channel design increases wind pressure and airflow velocity, effectively improving the heat dissipation effect.

[0014] 2. A reinforcing rib is provided at the airflow outlet. The reinforcing rib is connected to the end of each of the heat dissipation blades and together with the edge of the heat dissipation cover body to form an independent airflow outlet. The reinforcing rib closes part of the cross section of the airflow outlet, which is used to perform secondary throttling on the exhaust airflow, further increase the airflow velocity, and improve the heat dissipation effect.

[0015] 3. Without increasing the overall size of the motor, this invention effectively improves the heat dissipation of the motor, allowing the motor of the same volume to carry greater power, significantly reducing the risk of the motor burning out under high-speed, high-load operation, and increasing the overall reliability of the motor. [Attached Image Description] To more clearly illustrate the technical solutions in the embodiments of this application, 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 this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a three-dimensional perspective view of the heat dissipation structure of this application; Figure 2 This is a three-dimensional perspective view of the external rotor motor of this application; Figure 3 yes Figure 2 Exploded view; Figure 4 yes Figure 2 Top view; Figure 5 yes Figure 4 Cross-sectional view at point AA; Figure 6 This is a flowchart of the heat dissipation method for the external rotor motor of this application.

Detailed Implementation Methods

[0019] Please see Figures 1 to 6 A motor heat dissipation structure with a booster flow channel includes a heat dissipation cover body 1. The lower surface of the heat dissipation cover body 1 is provided with a plurality of heat dissipation blades 11 extending radially from the center to the periphery. Adjacent heat dissipation blades 11 and the top surface of the heat dissipation cover body 1 form a heat dissipation flow channel 12 for airflow. The axial height of the heat dissipation blades 11 decreases radially from the inside to the outside, so that the effective flow cross-sectional area of ​​the heat dissipation flow channel 12 gradually decreases in the direction of airflow.

[0020] In this embodiment, when the motor rotates and drives the heat sink body to rotate, the resulting centrifugal negative pressure draws external air through the bottom of the motor and the stator gap into the air intake area at the center of the heat sink. The airflow then enters the heat dissipation channel and flows radially outward. During this process, although the channel naturally widens as the radius increases, the effective flow cross-sectional area of ​​the heat dissipation channel is forcibly contracted in the direction of airflow because the axial height of the heat dissipation blades decreases radially from the inside to the outside. This overcomes the problem of airflow velocity attenuation caused by channel diffusion in the prior art. This variable cross-section design uses the principle of fluid continuity to force the airflow to continuously accelerate and build up a high wind pressure as it moves outward, and finally sprays out from the edge of the heat sink at a high velocity, thereby significantly improving the efficiency of removing heat from the inside of the motor and increasing the power limit and operational reliability of the motor in the same volume.

[0021] Furthermore, as a preferred embodiment of this solution and not a limitation thereof, the heat dissipation blade 11 includes a first blade portion 111 and a second blade portion 112 arranged from the inside out, and a transition slope 113 is provided between the first blade portion 111 and the second blade portion 112.

[0022] In this embodiment, the first blade portion 111 is located near the center of the heat sink and has a large axial height. Its main function is to capture and accommodate a sufficient amount of external cold air in the initial stage of air intake by utilizing the large flow channel space. The second blade portion 112 is located near the edge of the heat sink and has a smaller axial height. It is used to forcibly reduce the flow channel cross-section during the outward transport of airflow. The transition ramp 113 guides the airflow from the high-volume region to the low-volume region through a smooth slope. This gradual compression method not only follows the principles of fluid mechanics but also reduces the effective flow cross-sectional area to offset the velocity attenuation caused by the radial diffusion of airflow, thereby forcing the air... The increased airflow velocity and improved air pressure, compared to the vertical stepped abrupt structure, the transition ramp can significantly reduce the impact loss, eddy disturbance and wind noise of the airflow during compression, making the airflow smoother and more stable; the beneficial effect of this structure is that it achieves efficient outlet pressurization while ensuring a large intake volume, significantly improving the heat dissipation capacity of the motor's heat-generating core; in other possible embodiments, the slope angle of the transition ramp can be optimized and adjusted according to the speed and power of a specific motor, or multiple continuous or different slope transition ramps can be set between the first blade section and the second blade section to form a streamlined pressurization channel that conforms to specific aerodynamic characteristics.

[0023] Furthermore, as a preferred embodiment of this solution and not a limitation, the edge of the heat dissipation cover body 1 is provided with a reinforcing rib 13 connecting the heat dissipation blade 11. The reinforcing rib 13 is connected to the end of the heat dissipation blade 11. The reinforcing rib 13, together with the two adjacent heat dissipation blades 11 and the edge of the heat dissipation cover body 1, together form an independent airflow outlet 14.

[0024] In this embodiment, the reinforcing rib 13 not only serves as a structural support connecting the ends of adjacent heat dissipation blades 11 to enhance the overall rigidity and deformation resistance of the edge of the heat dissipation cover body 1, preventing displacement or vibration of the blades under high-speed centrifugal force, but more importantly, the reinforcing rib 13 physically blocks part of the cross-section of the blade gap, together with the adjacent blades and the edge of the cover, defining an independent airflow outlet 14 with reduced dimensions; its working principle is to use the reinforcing rib 13 to perform secondary throttling and rectification on the airflow about to flow out, that is, after the airflow has been compressed by the reduced blade height, at the outlet... The flow area is further reduced, forcing the airflow to generate a nozzle effect when passing through the narrow independent airflow outlet 14, converting pressure potential energy into kinetic energy, thereby significantly increasing the outlet air velocity and air pressure, preventing the airflow from diffusing or flowing back too early at the outlet, and ensuring that the heat is effectively carried away from the motor area by the high-speed jet; in other possible embodiments, the windward surface of the reinforcing rib 13 can be designed as a streamlined curved surface or an inclined surface with a specific guiding angle to reduce energy loss and noise caused by airflow impact, or the thickness of the reinforcing rib 13 can gradually change along the airflow direction to adjust the throttling ratio, thereby adapting to the heat dissipation requirements of motors with different power.

[0025] Furthermore, as a preferred embodiment of this solution and not a limitation, the heat dissipation cover body 1, the heat dissipation blades 11, and the reinforcing ribs 13 are integrally formed parts.

[0026] In this embodiment, the heat dissipation cover body 1, the heat dissipation blades 11, and the reinforcing ribs 13 are manufactured as a single, physically non-removable integral component through injection molding or metal die casting. Its working principle lies in using mold forming technology to eliminate assembly gaps and connection interfaces between components, thereby ensuring that the entire heat dissipation structure can act as a homogeneous, rigid whole to withstand centrifugal loads when the motor rotates at high speed. The beneficial effects of this integral molding structure are that it significantly improves the mechanical strength and dynamic balance stability of the motor, completely avoiding safety hazards such as loose screws, component separation, or abnormal noises that may occur under long-term vibration or high-speed operation in a split assembly structure. Simultaneously, the smooth, continuous integral surface eliminates flow channel gaps caused by assembly errors, effectively preventing high-pressure airflow leakage and unnecessary turbulence losses, ensuring the precise realization of the aerodynamic performance of the pressurized flow channel design, and greatly simplifying the production process and reducing manufacturing costs. This integral molding part can be injection molded using engineering plastics such as polycarbonate (PC) and nylon to achieve lightweighting, or die-cast using thermally conductive metal materials such as aluminum alloy and magnesium alloy to balance structural heat dissipation functions.

[0027] An external rotor motor includes a stator assembly 2, a rotor assembly 3 rotatably sleeved outside the stator assembly 2, and a motor heat dissipation structure with a booster flow channel as described in any of the preceding claims, wherein the heat dissipation cover body 1 is fixedly installed on the top end face of the rotor assembly 3.

[0028] In this embodiment, the stator assembly 2 serves as a stationary component providing electromagnetic driving force, while the rotor assembly 3 serves as a power output component rotating around the stator assembly 2. The heat dissipation cover body 1 is fixed to the top of the rotor assembly 3 and rotates synchronously at high speed. Its working principle is to use the rotational kinetic energy of the rotor itself to directly drive the heat dissipation cover to act as a centrifugal fan, thereby establishing an active heat dissipation cycle inside the motor: the centrifugal negative pressure generated by the high-speed rotation draws in external cold air from the bottom of the motor, causing it to flow through the internal magnetic gap between the stator assembly 2 and the rotor assembly 3 to carry away heat. Subsequently, the airflow enters the heat dissipation channel at the top and is accelerated to be discharged under the squeezing action of the pressurized channel structure. The beneficial effect of this layout is that it realizes the integrated integration of the heat dissipation structure and the motor power components, significantly reducing the operating temperature of the stator winding and permanent magnet without increasing additional energy consumption and volume, thereby improving the motor's overload capacity and service life. The heat dissipation cover body 1 can be fixed to the end face of the rotor assembly 3 by screw fastening, snap-fit ​​connection, or interference fit, and an air intake grille can be correspondingly opened on the base of the stator assembly 2 to maximize the air intake flow.

[0029] Furthermore, as a preferred embodiment of this solution and not a limitation thereof, the rotor assembly 3 includes a rotor housing 31, the rotor housing 31 including a central housing 311, an outer peripheral housing 312 and a plurality of connecting arms 313 connecting the central housing 311 and the outer peripheral housing 312, and an air intake region 32 forming a heat dissipation channel 12 between the central housing 311 and the outer peripheral housing 312.

[0030] In this embodiment, the central housing 311 is used to connect or cooperate with the motor shaft, the outer peripheral housing 312 is used to support the rotor magnets or yoke, and the connecting arm 313 acts as a radial support frame to firmly connect the two into one. At the same time, the hollow part between the frames forms an open air intake area 32. Its working principle is that the air intake area 32 directly opens the airflow channel between the internal cavity of the motor and the top heat dissipation cover, so that the heated air drawn in from the bottom of the motor and flowing through the stator coils and other heat-generating components under centrifugal negative pressure can smoothly pass through the top of the rotor housing 31. The airflow is blocked and directly enters the central low-pressure area of ​​the heat dissipation channel 12. The beneficial effect of this structure is that, while ensuring the structural strength and concentricity of the rotor assembly 3 at high speed through the connecting arm 313, the large-area air intake area 32 significantly reduces the air intake resistance, ensuring that sufficient cooling air can enter the upper pressurized channel to participate in heat exchange, thereby maximizing the overall efficiency of the heat dissipation system. The connecting arm 313 can be evenly distributed in three to six directions along the circumference, and the cross-sectional shape of the connecting arm 313 can be designed as an airfoil with an angle of attack to generate additional axial suction to assist air intake during rotation.

[0031] Furthermore, as a preferred embodiment of this solution and not a limitation thereof, the heat dissipation cover body 1 is provided with a first connecting hole 15, and the connecting arm 313 is provided with a second connecting hole 3131. Fasteners pass through the first connecting hole 15 and the second connecting hole 3131 to fix the heat dissipation cover body 1 on the connecting arm 313.

[0032] In this embodiment, by providing a first connecting hole 15 on the heat sink body 1 and axially aligning it with the second connecting hole 3131 on the rotor connecting arm 313, and applying axial locking force by using fasteners such as screws and bolts through the holes, the working principle is to establish a rigid mechanical connection between the heat sink and the rotor assembly, ensuring that the two maintain absolute coaxial synchronous movement when the motor rotates at high speed, thereby preventing the heat sink from loosening and falling off due to huge centrifugal force or vibration. The beneficial effect of this connection structure is that it makes full use of the solid connecting arm 313 existing in the rotor frame as a mounting base, cleverly avoiding the gap between the central shell and the outer shell. The hollow air intake area 32 between the two sides achieves a stable fixation while maximizing the effective flow area for airflow into the heat dissipation channel. This avoids blocking the air intake channel due to the addition of additional mounting brackets. The threaded connection method facilitates subsequent cleaning, maintenance, or replacement of the heat dissipation cover inside the motor. The first connecting hole 15 can be designed as a countersunk hole to accommodate the head of the fastener, reducing wind resistance and noise caused by surface protrusions. Alternatively, a spring washer or thread locking agent can be added at the fastener mating point to further enhance the anti-vibration and anti-loosening performance. The number and distribution of the connecting holes should be circumferentially symmetrical with the connecting arm 313 to ensure rotational dynamic balance.

[0033] Furthermore, as a preferred embodiment of this solution and not a limitation, the stator assembly 2 is provided with an airflow inlet 21 at its bottom and a through air intake channel 22 on the stator assembly 2. External airflow passes sequentially through the airflow inlet 21, the air intake channel 22, the air intake area 32, the heat dissipation channel 12, and the airflow outlet 14.

[0034] In this embodiment, an airflow inlet 21 is provided at the bottom of the stator assembly 2, and an air intake channel 22 that runs through the stator connects the external environment with the internal space of the rotor. The working principle is that the strong centrifugal negative pressure generated by the high-speed rotation of the heat dissipation cover body 1 installed on the top of the rotor is used as a power source to form a low-pressure center at the top of the motor, thereby forcing external cold air to be drawn in from the airflow inlet 21 at the bottom, flowing upward along the air intake channel 22 and directly passing over the surface of core heat-generating components such as the stator winding and iron core for heat exchange. Then, the airflow carrying heat passes through the air intake area 32 and is introduced into the heat dissipation channel 12, and is discharged from the airflow outlet 14 after being pressurized by the blades. The beneficial effect of this structure is that it realizes active deep cooling of the heat source inside the motor. Compared with the passive method of relying only on the outer shell for heat dissipation, it significantly improves the heat dissipation efficiency and prevents heat from accumulating inside the motor and causing performance degradation.

[0035] A heat dissipation method based on the external rotor motor described above includes the following steps: Step S1: The motor rotates, causing the heat dissipation cover to rotate synchronously. Under the action of centrifugal negative pressure, airflow is drawn in from the bottom of the motor and passes through the air intake channel 22 of the stator assembly 2; Step S2: The airflow passes through the air intake area 32 at the top of the rotor assembly 3 and enters the heat dissipation channel 12 below the heat dissipation cover; Step S3: Under the action of centrifugal force, the airflow flows radially towards the heat dissipation blades 11 whose height gradually decreases, continuously compressing the effective cross-sectional area of ​​the channel and keeping the airflow in a high wind pressure state; Step S4: When the high wind pressure airflow reaches the edge of the heat dissipation cover, it is enclosed by the reinforcing ribs 13 to form an independent airflow outlet 14 for secondary rectification and acceleration, and finally sprayed outwards at a high flow rate to remove heat.

[0036] In this embodiment, the high-speed rotation of the motor rotor serves as the primary power source. Steps S1 to S2 construct a bottom-up forced convection channel within the motor, using centrifugal negative pressure to draw in external cold air and allow it to flow through the stator assembly's intake channel. This directly cools the core heat sources, such as the stator windings, solving the problem of heat dissipation within a closed motor. Step S3 guides the airflow through a gradually decreasing heat dissipation channel, utilizing the contraction of physical space (reducing the effective flow cross-sectional area) to counteract the natural expansion and deceleration effect caused by the increased perimeter as the airflow diffuses radially outward. This forces the airflow to maintain high pressure and high velocity throughout its outward flow. Finally, step S4 utilizes the independent airflow outlet formed by reinforcing ribs to create a nozzle effect, performing secondary rectification and accelerated jetting of the airflow to prevent turbulence or backflow at the outlet. The beneficial effect of this method is that it achieves active and efficient heat dissipation throughout the entire motor path, significantly improving the power density and operational reliability of a motor of the same volume.

[0037] The working principle of this embodiment is as follows: The rotating motor drives the heat sink cover to rotate synchronously at high speed. The centrifugal negative pressure generated by the rotating blades creates a forced convection channel from bottom to top inside the motor. This forces external cold air to overcome flow resistance and enter through the airflow inlet at the bottom of the stator assembly. The airflow flows upward along the intake channel and directly washes over the heat sources such as the stator windings and the iron core for heat exchange. The airflow carrying heat then passes through the intake area at the top of the rotor assembly and enters the low-pressure area in the center of the heat sink cover. Under the action of centrifugal force, it is transported radially outward. During this process, the airflow flows through the heat sink channel with a gradually decreasing axial height. The continuous contraction of the effective flow cross-sectional area of ​​the channel counteracts the natural expansion and deceleration effect caused by the radial diffusion of the airflow, thereby efficiently converting the rotational mechanical energy into the pressure potential energy and kinetic energy of the airflow. Finally, when the compressed high-pressure airflow reaches the edge of the heat sink cover, it generates a nozzle effect through the contraction-type independent airflow outlet formed by the reinforcing ribs. After secondary rectification and acceleration, it is ejected outward at high velocity, thereby achieving rapid heat removal from the inside of the motor.

[0038] The above are implementation methods provided in conjunction with specific content, and it is not intended that the specific implementation of this application is limited to these descriptions. Any methods or structures that are similar to those of this application, or any technical deductions or substitutions made based on the concept of this application, should be considered within the scope of protection of this application.

Claims

1. A motor heat dissipation structure with a pressure boosting flow channel, characterized in that, The device includes a heat dissipation cover body (1), and the lower surface of the heat dissipation cover body (1) is provided with a plurality of heat dissipation blades (11) extending radially from the center to the surrounding area. The adjacent heat dissipation blades (11) and the top surface of the heat dissipation cover body (1) form a heat dissipation channel (12) for airflow. The axial height of the heat dissipation blades (11) decreases radially from the inside to the outside, so that the effective flow cross-sectional area of ​​the heat dissipation channel (12) gradually decreases in the direction of airflow.

2. The motor heat dissipation structure with a pressure boosting flow channel according to claim 1, characterized in that, The heat dissipation blade (11) includes a first blade portion (111) and a second blade portion (112) arranged from the inside to the outside, and a transition slope (113) is provided between the first blade portion (111) and the second blade portion (112).

3. The motor heat dissipation structure with a pressure boosting flow channel according to claim 1, characterized in that, The edge of the heat dissipation cover body (1) is provided with a reinforcing rib (13) that connects to the heat dissipation blade (11). The reinforcing rib (13) is connected to the end of the heat dissipation blade (11). The reinforcing rib (13), together with the two adjacent heat dissipation blades (11) and the edge of the heat dissipation cover body (1), forms an independent airflow outlet (14).

4. The motor heat dissipation structure with a pressure boosting flow channel according to claim 3, characterized in that, The heat dissipation cover body (1), the heat dissipation blade (11), and the reinforcing rib (13) are integrally formed parts.

5. An external rotor motor, characterized in that, The device includes a stator assembly (2), a rotor assembly (3) rotatably fitted outside the stator assembly (2), and a motor heat dissipation structure with a booster flow channel as described in any one of claims 1 to 4, wherein the heat dissipation cover body (1) is fixedly installed on the top end face of the rotor assembly (3).

6. The external rotor motor according to claim 5, characterized in that, The rotor assembly (3) includes a rotor housing (31), which includes a central housing (311), an outer peripheral housing (312), and multiple connecting arms (313) connecting the central housing (311) and the outer peripheral housing (312). An air intake area (32) is formed between the central housing (311) and the outer peripheral housing (312) to communicate with the heat dissipation channel (12).

7. The external rotor motor according to claim 6, characterized in that, The heat dissipation cover body (1) is provided with a first connection hole (15), and the connecting arm (313) is provided with a second connection hole (3131). Fasteners pass through the first connection hole (15) and the second connection hole (3131) to fix the heat dissipation cover body (1) on the connecting arm (313).

8. The external rotor motor according to claim 6, characterized in that, The stator assembly (2) has an airflow inlet (21) at its bottom and a through air intake channel (22) on its top. External airflow passes through the airflow inlet (21), the air intake channel (22), the air intake area (32), the heat dissipation channel (12), and the airflow outlet (14) in sequence.

9. A heat dissipation method for an external rotor motor according to claim 5, characterized in that, Includes the following steps: Step S1: The motor rotates and drives the heat sink cover to rotate synchronously. Under the action of centrifugal negative pressure, the airflow is drawn in from the bottom of the motor and passes through the air intake channel (22) of the stator assembly (2); Step S2: The airflow passes through the air intake area (32) at the top of the rotor assembly (3) and enters the heat dissipation channel (12) below the heat sink cover; Step S3: Under the action of centrifugal force, the airflow flows radially towards the heat dissipation blades (11) whose height gradually decreases, continuously compressing the effective cross-sectional area of ​​the channel, so that the airflow maintains a high wind pressure state; Step S4: When the high wind pressure airflow reaches the edge of the heat sink cover, it is enclosed by the reinforcing ribs (13) to form an independent airflow outlet (14) for secondary rectification and acceleration, and finally sprays outwards at a high flow rate to take away heat.

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