Brushless motor heat dissipation structure

Abstract

The application discloses a heat dissipation structure of a brushless motor, which comprises a shell, a rotor shaft core of a permanent magnet and a coil, the rotor shaft core of the permanent magnet and the coil are assembled in the shell, both ends of the shell are provided with air holes for air flow circulation, the shell and the coil are connected together to rotate together, a wing section is arranged at a central position of the shell, the wing section is provided with a through hole for the rotor shaft core to pass through, a plurality of cavities are arranged around the wing section, and a movable vane assembly is arranged in the cavity; the movable vane assembly comprises a shaft rod, a torsion spring and a vane, the shaft rod is arranged in the cavity, the torsion spring and the vane are sleeved with the shaft rod at a first end, and both ends of the torsion spring are connected with the vane and the shell respectively; the coil in the process of being electrified drives the shell to rotate, and the centrifugal force drives the vane of the shell to extend out of the shell, and the shell after stopping rotating retracts the vane in the shell through the torsion spring. It has the advantages of simple structure, compact cooperation, reasonable design and the like; therefore, it is a product with superior performance in both technology and economy.

Description

[Technical Field] This invention mainly relates to a heat dissipation structure for a brushless motor. [Background Technology] Brushless motors are widely used in power tools, home appliances, drones, and electric vehicles due to their high efficiency, long lifespan, and low noise. However, high-power-density brushless motors generate a large amount of heat during prolonged continuous operation, particularly in the coils and permanent magnet rotor. Insufficient heat dissipation can lead to excessively high motor temperatures, affecting electromagnetic performance, reducing insulation lifespan, and even causing permanent demagnetization or burnout. Current brushless motor cooling methods primarily rely on natural cooling, but this depends on surface cooling fins or radiation from the casing, which has limited effectiveness. Therefore, we have improved the structure of our brushless motor. [Summary of the Invention] To address at least one of the aforementioned problems, this invention proposes a novel structural solution. The heat dissipation structure of this brushless motor adopts the following technical solution: A brushless motor heat dissipation structure includes a housing, a permanent magnet rotor shaft, and a coil. The permanent magnet rotor shaft and coil are assembled inside the housing. Ventilation holes are provided at both ends of the housing for airflow. The housing and coil are connected together to rotate together. A vane section is provided at the center of the housing, and the vane section has through holes for the rotor shaft to pass through. The vane section is surrounded by several cavities, and movable blade assemblies are provided in the cavities. The movable blade assembly includes a shaft, a torsion spring, and blades. The shaft is located in the cavity, and the first ends of the torsion spring and the blades are sleeved on the shaft. The two ends of the torsion spring are respectively connected to the blades and the housing. The energized coil drives the housing to rotate, and the centrifugal force drives the blades of the housing to extend out of the housing. After the housing stops rotating, the torsion spring retracts the blades back into the housing.

[0004] Preferably, the inner side of the housing is provided with ribs, which are embedded between the coils so that the rotating coils drive the housing to rotate.

[0005] Preferably, the housing has a cavity, and the wing portions are respectively disposed at the top or bottom of the cavity.

[0006] Preferably, the rotor shaft core is provided with a first stop and a second stop at its end, and the rotor shaft core passes through the top of the housing so that the first stop and the second stop are located on both sides of the top of the housing, so as to maintain a stable connection between the rotor shaft core and the housing.

[0007] Preferably, the shaft includes a first rod segment, a second rod segment, and a spring. The first rod segment has an inner cavity, the spring is placed in the inner cavity, and the second rod segment is inserted into the inner cavity and connected to the spring.

[0008] Preferably, the top of the inner cavity extends inward to form a first stop, and the end of the second rod segment extends outward to form a second stop. The first and second stops are movably connected to restrict the second rod segment from disengaging from the first rod segment.

[0009] Preferably, the second rod segment has a recessed hole.

[0010] The beneficial effects of this invention compared to the prior art are as follows: This invention provides a heat dissipation structure for a brushless motor. It utilizes the centrifugal force generated when the coil is energized and drives the housing to rotate, automatically ejecting the movable blade assembly from the cavity. This achieves on-demand heat dissipation without an additional power source. When the motor stops rotating, the blades automatically retract into the cavity under the action of torsion springs, avoiding wind resistance, noise, and impact damage caused by continuously exposed blades. It also facilitates the overall packaging and transportation of the motor. Secondly, both ends of the housing are equipped with wing sections and blades. Regardless of whether the motor rotates forward or backward, at least one blade always blows cooling airflow into the housing cavity. The airflow flows extensively along the coil axis across the coil and permanent magnet surface, significantly improving heat dissipation uniformity and cooling efficiency. Thirdly, the shaft adopts a two-stage spring telescopic structure, combined with a concave hole design, enabling quick assembly and non-destructive disassembly of the blades, reducing manufacturing and maintenance costs. Furthermore, the housing is fixed to the coil via internal ribs, eliminating the need for additional connecting parts, resulting in a compact structure. The first and second stops at both ends of the rotor shaft form axial limits with the housing end face, ensuring reliable connection during high-speed rotation. It has the advantages of simple structure, compact fit, and reasonable design; therefore, it is a product with superior performance in both technology and economy. [Attached Image Description] Figure 1 This is a schematic diagram of the heat dissipation structure of the brushless motor in a preferred embodiment of the present invention; Figure 2 This is an exploded view of the heat dissipation structure of the brushless motor in a preferred embodiment of the present invention. Figure 3 This is a schematic diagram of the blade rotating out of the cavity in a preferred embodiment of the present invention; Figure 4 A schematic diagram of the shaft structure in a preferred embodiment of the present invention; Figure 5 This is a schematic diagram of the blade's folded and unfolded state in a preferred embodiment of the present invention.

Detailed Implementation Methods

[0013] In this invention, unless otherwise explicitly specified and limited, the terms "assembly," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can also refer to a mechanical connection; they can refer to a direct connection or a connection through an intermediate medium; or they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0014] The following description, in conjunction with the accompanying drawings, further illustrates specific embodiments of the present invention, making the technical solution and its beneficial effects clearer and more explicit. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, but should not be construed as limiting the invention.

[0015] The preferred embodiments provided by the present invention are as follows: Figures 1-5 As shown, a brushless motor heat dissipation structure includes a housing 1, a permanent magnet rotor core 2 and a coil 3. The permanent magnet rotor core 2 and the coil 3 are assembled inside the housing 1, and the two ends of the housing 1 are provided with vent holes 4 for airflow. The inner side of the housing 1 is provided with ribs 5, which are embedded between the coils 3 to connect the housing 1 and the coils 3 together. The rotating coils 3 can drive the housing 1 to rotate. The center of the housing 1 is provided with a vane section 6, which has a through hole 61 for the rotor shaft core 2 to pass through. The vane section 6 is provided with several cavities 62, and the cavities 62 are provided with movable blade assemblies 7. The movable blade assembly 7 includes a shaft 71, a torsion spring 72, and a blade 73. The shaft 71 is located inside the cavity 62. The first ends of the torsion spring 72 and the blade 73 are sleeved on the shaft 71. The blades are provided with through holes for the shaft to pass through. The two ends of the torsion spring 72 are connected to the blade 73 and the housing 1, respectively. The energized coil 3 drives the housing 1 to rotate, and the centrifugal force drives the blade 73 of the housing 1 to extend out of the vane portion 6. After the rotation stops, the housing 1 retracts the blade 73 into the vane portion 6 through the torsion spring 72. The torque strength of the torsion spring 72 is selected according to the relevant parameters of the motor.

[0016] The housing 1 has a cavity 8, and the blades 6 are respectively located at the top or bottom of the cavity 8, so that the blades 73 are located at both ends of the coil 3, ensuring that the airflow generated by the blades 73 blows into the cavity 8 over a wide range. At the same time, the blades 73 designed at both ends can blow air into the cavity 8 regardless of whether the housing 1 is rotated forward or backward.

[0017] The rotor shaft core 2 is provided with a first stop 9 and a second stop 10 at its end. The first stop 9 and the second stop 10 adopt a conventional collar structure. After the rotor shaft core 2 passes through the housing 1, it is fixed to the rotor shaft core 2 by structural adhesive 11. The rotor shaft core 2 passes through the top of the housing 1 so that the first stop 9 and the second stop 10 are located on both sides of the top of the housing 1, so as to maintain a stable connection between the rotor shaft core 2 and the housing 1.

[0018] The shaft 71 includes a first segment 711, a second segment 712, and a spring 713. The first segment 711 has an inner cavity 714, and the spring 713 is placed in the inner cavity 714. The second segment 712 is inserted into the inner cavity 714 and connected to the spring 713. A first stop 715 extends inward from the top of the inner cavity 714, and a second stop 716 extends outward from the end of the second segment 712. The first stop 715 and the second stop 716 are movably connected to prevent the second segment 712 from disengaging from the first segment 711.

[0019] Cavity 62 has an open end for blade 73 to extend out. The upper and lower ends of cavity 62 are respectively provided with shaft holes 13 and blind holes 14. During assembly, the second rod segment 712 is pressed down, and then the shaft 71 is pushed to the position of shaft hole 13. Under the action of spring 713, the second rod segment 712 returns to its original position and engages with shaft hole 13. The second rod segment 712 is provided with a recessed hole 717. During disassembly, the needle tube 15 is inserted into the recessed hole 717 to press down the second rod segment 712, reducing the length of shaft 71 and thus allowing disassembly. Blade 73 can adopt a conventional blade structure. The appropriate blade size is selected according to the motor size. The blades 73 at both ends face opposite directions to adapt to the forward and reverse rotation of the motor. The leading end of blade 73 and torsion spring 72 pass through shaft 71. The two ends of torsion spring 72 are respectively fixed to blind hole 14 and blade 73.

[0020] By changing the alternating frequency and waveform of the current wave input to the stator coil of the brushless motor, a magnetic field rotating around the geometric axis of the motor is formed around the winding coil, thereby causing the housing 1 and the coil 3 to rotate. As the housing 1 rotates, it generates centrifugal force, which throws the blade 73 in the cavity 62 out of the cavity 62. The walls on both sides of the cavity 62 limit the extension range of the blade 73. As the blade 73 and the housing 1 rotate together, the blade 73 cuts the air to form an airflow. Since the blade 73 is located at the end of the coil 3, the airflow can blow into the cavity 8 over a large area, thereby cooling the motor.

[0021] In the description of this specification, references to terms such as "an embodiment," "preferred," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. Illustrative expressions of the above terms in this specification do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0022] Based on the above description of the structure and principle, those skilled in the art should understand that the present invention is not limited to the specific embodiments described above. Improvements and substitutions made using techniques known in the art based on the present invention all fall within the protection scope of the present invention and should be defined by the claims.

Claims

1. A heat dissipation structure for a brushless motor, characterized in that: It includes a housing, a permanent magnet rotor shaft, and a coil. The permanent magnet rotor shaft and coil are assembled inside the housing. Ventilation holes are provided at both ends of the housing for airflow. The housing and coil are connected together so that they rotate together. A vane section is provided at the center of the housing, and the vane section has through holes for the rotor shaft to pass through. The vane section is surrounded by several cavities, and movable blade assemblies are provided in the cavities. The movable blade assembly includes a shaft, a torsion spring, and blades. The shaft is located in the cavity, and the first ends of the torsion spring and blades are sleeved on the shaft. The two ends of the torsion spring are connected to the blades and the housing, respectively. The energized coil drives the housing to rotate, and the centrifugal force drives the blades of the housing to extend out of the housing. After the housing stops rotating, the torsion spring retracts the blades back into the housing.

2. The heat dissipation structure for a brushless motor according to claim 1, characterized in that: The inner ring of the housing is provided with ribs, which are embedded between the coils so that the rotating coils drive the housing to rotate.

3. The heat dissipation structure for a brushless motor according to claim 1, characterized in that: The shell has a cavity, and the wing parts are respectively located at the top or bottom of the cavity.

4. The heat dissipation structure for a brushless motor according to claim 1, characterized in that: The rotor shaft is provided with a first stop and a second stop at its end. The rotor shaft passes through the top of the housing so that the first stop and the second stop are located on both sides of the top of the housing to keep the rotor shaft and the housing firmly connected.

5. The heat dissipation structure for a brushless motor according to claim 1, characterized in that: The shaft includes a first segment, a second segment, and a spring. The first segment has an inner cavity, the spring is placed in the inner cavity, and the second segment is inserted into the inner cavity and connected to the spring.

6. The heat dissipation structure for a brushless motor according to claim 5, characterized in that: The top of the inner cavity extends inward to form a first stop, and the end of the second rod segment extends outward to form a second stop. The first and second stops are movably connected to restrict the second rod segment from disengaging from the first rod segment.

7. The heat dissipation structure for a brushless motor according to claim 5, characterized in that: The second section has a recessed hole.

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