Miniature heat dissipation fan

Abstract

The micro heat-dissipating fan provided by the utility model has high space utilization, high driving efficiency and high heat-dissipating efficiency.

Description

Technical Field This utility model relates to the field of heat dissipation technology, and in particular to a miniature cooling fan. Background Technology As electronic products become increasingly miniaturized and high-performance, they generate a significant amount of heat during operation. If this heat cannot be dissipated in time, the internal temperature of the electronic product will rise rapidly, severely affecting the performance and reliability of the internal electronic components. Miniature cooling fans are used in electronic products, typically employing a combination of magnets and coils to drive the blades to rotate and dissipate heat.

[0001] In related technologies, the coils of miniature cooling fans are usually plastic-wrapped coils. The plastic wrapping is not conducive to the heat dissipation of the coil after it is energized and heated. In addition, it not only has high production costs, but also occupies a large axial space, which is not conducive to the ultra-thin design of miniature cooling fans. Furthermore, the magnetic gap between the magnet and the coil cannot be compressed, and due to the low utilization rate of internal space, the number of coils is limited, resulting in low driving efficiency of miniature fans and the inability to further improve the heat dissipation efficiency of miniature cooling fans.

[0002] Therefore, it is necessary to provide a new miniature cooling fan to solve the above-mentioned technical problems. Utility Model Content The purpose of this invention is to provide a miniature cooling fan with high space utilization, high driving efficiency, and high heat dissipation efficiency.

[0003] To achieve the above objectives, this utility model proposes a miniature cooling fan, which includes: An outer casing having a receiving space; A rotor assembly, which is housed within the housing space, includes a rotating shaft rotatably connected to the housing, a bracket mounted on the rotating shaft, fan blades connected to the bracket, and a magnet fixed to the bracket. A stator assembly, comprising a flexible circuit board fixed to the housing and housed within the housing space, and a coil fixed to the flexible circuit board facing the magnet, the coil being spaced apart from the magnet along the axial direction of the rotating shaft, and the coil being a hollow coil; The flexible circuit board has a through-hole groove, and the coil has a winding groove. The through-hole groove and the winding groove are arranged opposite each other along the axial direction. The coil includes an inner winding layer surrounding the winding groove, an outer winding layer opposite to the inner winding layer, a first lead extending from the inner winding layer, and a second lead extending from the outer winding layer and soldered to the flexible circuit board. The first lead extends into the through-hole groove and extends through the through-hole groove to the side of the outer winding layer away from the winding groove before being soldered to the flexible circuit board.

[0004] Preferably, the coil includes an upper surface facing the magnet and a lower surface disposed opposite to the upper surface; along the axial direction, the distance between the upper surface and the flexible circuit board is equal to the distance between the upper surface and the lower surface.

[0005] Preferably, the coil includes a suspension portion located above the hollowed-out groove, and the first lead extends into the hollowed-out groove and is attached to the lower surface of the suspension portion.

[0006] Preferably, the cutout groove includes a first opening opposite to the winding groove and a second opening located on the side of the suspension portion away from the winding groove. The first lead extends through the first opening to below the lower surface and extends through the second opening out of the cutout groove before being soldered to the flexible circuit board.

[0007] Preferably, there are 3N coils and 3N slots, where N is a natural number greater than 1; the 3N coils are three-phase coils and are evenly spaced along the circumference of the rotating shaft.

[0008] Preferably, the flexible circuit board is provided with a first pad for soldering to the first lead and a second pad for soldering to the second lead, and the fan blade is disposed opposite to the first pad and the second pad along the axial direction.

[0009] Preferably, the housing includes a base and a cover plate that cooperate with each other to form the receiving space. The base has a bottom cover that is spaced apart from the cover plate in the axial direction and a side wall that connects the bottom cover and the cover plate. The two ends of the rotating shaft in the axial direction are respectively rotatably connected to the bottom cover and the cover plate. The flexible circuit board is fixed to the surface of the bottom cover facing the cover plate. The cover plate is provided with an air outlet that connects the receiving space to the outside. The side wall is provided with a notch that connects the receiving space to the outside.

[0010] Preferably, the miniature cooling fan further includes a driver chip, and the bottom cover has a through hole therethrough. The driver chip is housed in the through hole and fixed to the surface of the flexible circuit board away from the coil. Along the axial direction, the projection of the driver chip is located between two adjacent cutouts.

[0011] Preferably, the bottom cover includes a protruding post extending from the surface facing the cover plate toward the cover plate, the protruding post extending sequentially into the hollow groove and the winding groove, and the projection of the protruding post in the axial direction is rectangular or racetrack-shaped.

[0012] Preferably, the bracket includes a support portion sleeved on the rotating shaft and an extension portion extending from the support portion away from the rotating shaft. The magnet is fixed to the surface of the extension portion facing the coil, and the fan blade is connected to the surface of the extension portion away from the coil. The fan blade includes a connecting portion connected to the extension portion and a plurality of blades connected to the connecting portion and spaced apart. The connecting portion includes a straight portion fixed to the surface of the extension portion away from the coil and a bent portion extending from the straight portion to fit against the surface of the magnet away from the rotating shaft. The plurality of blades are connected to the bent portion. Along the axial direction, the end face of the bent portion away from the straight portion is flush with the surface of the magnet facing the coil.

[0013] Compared with related technologies, the miniature cooling fan provided by this utility model features a hollow coil with a winding groove and a hollow slot on a flexible circuit board. The hollow slot and the winding groove are aligned along the axial direction of the rotating shaft, allowing the first lead extending from the inner winding layer of the coil to extend into the hollow slot and then through the hollow slot to the outer winding layer of the coil on the side away from the winding groove before being soldered to the flexible circuit board. The second lead from the outer winding layer is directly led out and soldered to the flexible circuit board. By leading the first lead out through the winding groove, the coil and the flexible circuit board are ensured to be in close contact with the plane, eliminating the need to clamp the first lead between the flexible circuit board and the coil. This reduces the overall height of the stator assembly composed of the coil and the flexible circuit board, which is beneficial for the miniature cooling fan to be thinner. It also increases the design freedom of the distance between the magnet and the coil, allowing the thickness of the magnet to be increased to increase the driving force and thus increase the fan blade speed to improve heat dissipation efficiency. Attached Figure Description To more clearly illustrate the technical solutions in the embodiments of this utility model, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort, wherein: Figure 1 This is a perspective view of the miniature cooling fan in this utility model; Figure 2 This is an exploded view of the miniature cooling fan in this utility model; Figure 3 for Figure 1 Sectional view along line AA; Figure 4 for Figure 3 Enlarged view of section B in the middle; Figure 5 This is a top view of the miniature cooling fan in this utility model after removing the base; Figure 6This is a perspective view of the stator assembly in the miniature cooling fan of this utility model; Figure 7 This is a perspective view of the miniature cooling fan in this utility model from another angle. Figure 8 for Figure 7 A cross-sectional view along the CC line.

[0014] Figure 9 This is a perspective view of the coil in the miniature cooling fan of this utility model. Detailed Implementation 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.

[0015] like Figure 1-2 As shown, the present invention provides a miniature cooling fan 1000, which includes a housing 100 having a receiving space 110, a rotor assembly 200 received in the receiving space 110, and a stator assembly 300 fixed to the housing 100.

[0016] Specifically, such as Figure 2 , Figure 3 as well as Figure 7 As shown, the outer casing 100 includes a base 120 and a cover plate 130 that cooperate with each other to form a receiving space 110. The base 120 has a bottom cover 121 spaced axially from the cover plate 130 and a side wall 122 connecting the bottom cover 121 and the cover plate 130. The cover plate 130 has an air outlet 131 that connects the receiving space 110 to the outside. Furthermore, to increase airflow, in this embodiment, the side wall 122 also has a notch 123 that connects the receiving space 110 to the outside.

[0017] The rotor assembly 200 includes a rotating shaft 210 rotatably connected to the bottom cover 121 and the cover plate 130 at both ends, a bracket 220 mounted on the rotating shaft 210, a fan blade 230 connected to the bracket 220, and a magnet 240 fixed to the bracket 220.

[0018] like Figures 2-4 As shown, the stator assembly 300 includes a flexible circuit board 310 fixed to the bottom cover 121 and housed within the housing space 110, and a coil 320 fixed to the flexible circuit board 310 facing the magnet 240. The coil 320 is spaced apart from the magnet 240 along the axial direction of the shaft 210. The coil 320 is electrically connected to the flexible circuit board 310. When energized, the coil 320 interacts with the magnet 240, generating a driving force that causes the shaft 210 to rotate the fan blades 230 on the bracket 220, thereby achieving heat dissipation.

[0019] like Figures 2-9As shown, in this embodiment, the coil 320 is a hollow coil with a winding groove 321. Compared with the plastic-wrapped coil in the prior art, this reduces the space occupied by the coil, thereby reducing the thickness of the stator assembly along the axial direction and increasing the design freedom of the magnet, the coil, and the magnetic gap between them. The flexible circuit board 310 has a through-hole groove 311, which is directly opposite to the winding groove 321 along the axial direction. Specifically, the coil 320 includes an inner winding layer 322 surrounding a winding groove 321, an outer winding layer 323 opposite to the inner winding layer 322, a first lead 324 extending from the inner winding layer 322, and a second lead 325 extending from the outer winding layer 323 and soldered to the flexible circuit board 310. The first lead 324 extends into the cutout groove 311 and extends through the cutout groove 311 to the side of the outer winding layer 323 away from the winding groove 321 before being soldered to the flexible circuit board 310. The first lead 324 and the second lead 325 are respectively soldered to the flexible circuit board 310 to form a conductive path to supply power to the coil 320. Specifically, the flexible circuit board 310 is provided with a first pad 312 soldered to the first lead 324 and a second pad 313 soldered to the second lead 325, with the first pad 312 and the second pad 313 spaced apart.

[0020] It is understandable that, since the voice coil 320 is a multi-layered winding structure formed by winding wires from the inside out, it has multiple winding layers; therefore, the inner winding layer 322 can be the innermost winding layer, or it can be several winding layers close to the winding groove 321, as long as its first lead 324 can be led out from the hollow groove 311, which is not limited here; similarly, the outer winding layer 323 can be the outermost winding layer, or it can be several winding layers including the outermost winding layer, which is not limited here.

[0021] like Figures 3-8As shown, the coil 320 further includes an upper surface 326 facing the magnet 240 and a lower surface 327 disposed opposite to the upper surface 326. In this embodiment, the second lead 32 is led out from the outer winding layer 323, so it can be directly soldered to the flexible circuit board 310 without occupying the space in the thickness direction of the coil 320, that is, the space in the axial direction of the rotating shaft 210. The first lead 324 is led out from the inner winding layer 322. Whether it is led out directly from the upper surface 326 or the lower surface 327 of the coil 320 along the axial direction, it will occupy the gap between the coil 320 and the magnet 240, which is not conducive to the thinning of the miniature cooling fan 1000. Therefore, by aligning the winding groove 321 of the hollow coil 320 with the cutout groove 311 of the flexible circuit board 310, the first lead 324, drawn from the inner winding layer 322 of the coil 320, can extend into the cutout groove 311 and further extend through the cutout groove 311 to the side of the outer winding layer 323 away from the winding groove 321, i.e., to the outside of the coil 320, thereby being soldered to the flexible circuit board 310. Since the first lead 324 is drawn out through the winding groove 311, This ensures that the coil 320 and the flexible circuit board 310 are in planar contact, preventing the first lead 324 from being sandwiched between the flexible circuit board 310 and the coil 320, thus improving the bonding strength between them. Furthermore, it prevents the first lead 324 from extending above the coil 320, occupying the gap between the magnet 240 and the coil 320, thereby compressing the overall height of the stator assembly 300 composed of the coil 320 and the flexible circuit board 310, which is beneficial for the thinning of the miniature cooling fan 1000. Further, the reduced overall height of the stator assembly 300 also increases the design freedom of the distance between the magnet 240 and the coil 320. The thickness of the magnet 240 can be increased to increase the driving force, thereby increasing the speed of the fan blade 230 to improve heat dissipation efficiency. It also allows for a significant reduction in the thickness of the miniature cooling fan 1000 while maintaining the same fan blade 230 size.

[0022] It is understandable that the coil 320 is flatly attached to the flexible circuit board 310, and the distance between the upper surface 326 and the flexible circuit board 310 along the axial direction of the rotating shaft 210 is equal to the distance between the upper surface 326 and the lower surface 327. That is, the first lead 324, which is drawn from the inner winding layer 322 of the coil 320, extends out through the cutout groove 311 and does not occupy the installation height of the coil 320.

[0023] Specifically, the coil 320 includes a suspension portion 328 located above the hollow groove 311, and a first lead 324 extends into the hollow groove 311 and is attached to the lower surface 327 of the suspension portion 328. It can be understood that the first lead 324 is drawn from the inner winding layer 322 of the suspension portion 328.

[0024] Furthermore, the cutout groove 311 includes a first opening 3111 disposed opposite to the winding groove 321 and a second opening 3112 located on the side of the suspension portion 328 away from the winding groove 321. The first lead wire 324 extends through the first opening 3111 to below the lower surface 327 of the suspension portion 328 and extends out of the cutout groove 311 through the second opening 3112 before being soldered to the first pad 312 on the flexible circuit board 310.

[0025] To further improve the heat dissipation efficiency of the miniature cooling fan 1000, there are 3N coils 320, where N is a natural number greater than 1. Correspondingly, there are also 3N slots 311. These 3N coils 320 are three-phase coils and are evenly spaced along the circumference of the rotating shaft 210, effectively reducing torque pulsation, improving the operational stability of the miniature cooling fan 1000, and reducing noise during fan operation. It is understood that each coil 320 adopts the same design, and the opening shape and size of each slot 311 are identical; that is, the first lead 324 and the second lead 325 both originate from the same position. Figure 5 As shown, 3N slots 311 are arranged at equal intervals along the circumference of the rotating shaft 210. The length direction of each slot 311 forms a certain angle with the radial direction of the rotating shaft 210, and each slot 311 is set at the same angle. That is, the 3N slots 311 are arranged in a rotating array along the circumference of the rotating shaft 210, thereby achieving a more uniform process, improving the degree of automation, and reducing production costs. In this embodiment, there are 6 coils 320. In other embodiments, the number can be set according to actual needs, or it can be set to 2N. This is not limited here.

[0026] In this embodiment, the first pad 312 and the second pad 313 are arranged opposite each other along the axial direction to avoid the first lead 324 and the second lead 325 extending too far and interfering with the rotation of the fan blade 230. In other embodiments, the first pad 312 and the second pad 313 may also be arranged in a position not directly opposite the fan blade 230, depending on the actual situation.

[0027] like Figures 5-8As shown, the miniature cooling fan 1000 also includes a driver chip 400. A through hole 124 is provided on the bottom cover 121, through which the driver chip 400 is housed. The driver chip 400 is contained within the through hole 124 and fixed to the surface of the flexible circuit board 310 away from the coil 320. It is understood that the driver chip 400 is electrically connected to the flexible circuit board 310 for initial positioning of the rotor assembly 200 and continuous operation commutation control during driving. Compared to an externally mounted chip structure, housing the driver chip 400 within the through hole 124 results in higher device integration and improved space utilization. Furthermore, the driver chip 400 in this embodiment integrates a Hall sensor, requiring only a single chip and reducing costs. Along the axial direction, the projection of the driver chip 400 is located between two adjacent cutout slots 311.

[0028] like Figure 2 , Figure 8 As shown, to further enhance the connection stability between the coil 320 and the flexible circuit board 310, the bottom cover 121 includes a protruding post 125 extending from the surface facing the cover plate 130 toward the cover plate 130. This protruding post 125 extends sequentially into the hollow groove 311 and the winding groove 321. Furthermore, the protruding post 125 extends into the winding groove 321 inside the coil 320, enhancing the bonding strength between the coil 320 and the bottom cover 121, effectively improving the fixing stability of the coil 320. Specifically, from... Figure 2 As can be seen, the projection of the protrusion 125 along the axial direction is rectangular or racetrack-shaped, thereby preventing the coil 320 from rotating. Optionally, the protrusion 125 does not extend into the winding groove 321 along the axial direction, that is, the height of the protrusion 125 along the axial direction is lower than the thickness of the coil 320 along the axial direction, thus providing space for adhesive application, thereby achieving adhesive fixation between the coil 320 and the bottom cover 121. In this embodiment, the bottom cover 121 is also provided with a support wall 126 that protrudes towards the cover plate 130 and is spaced apart from the protrusion 125. The support wall 126 surrounds and forms a receiving cavity 127 for accommodating the rotating shaft 210. Specifically, the rotor assembly 200 also includes a bearing 250 sleeved on the outside of the rotating shaft 210, and the bearing 250 is also accommodated in the receiving cavity 127. It is understood that the flexible circuit board 310 is provided with a mounting hole 312 located in the middle, and is sleeved on the outside of the support wall 126 through the mounting hole 312 to be installed to the bottom cover 121.

[0029] In this embodiment, the bracket 220 includes a support portion 221 sleeved on the rotating shaft 210 and an extension portion 222 extending from the support portion 221 away from the rotating shaft. The magnet 240 is fixed to the surface of the extension portion 222 facing the coil 320. The fan blade 230 is connected to the surface of the extension portion 222 away from the coil 320. Specifically, the fan blade 230 includes a connecting portion 231 connected to the extension portion 222 and a plurality of blades 232 connected to the connecting portion 231 and spaced apart. The connecting portion 231 includes a straight portion 2311 fixed to the surface of the extension portion 222 away from the coil 320 and a bent portion 2312 extending from the straight portion 2311 to fit the surface of the magnet 240 away from the rotating shaft 210. The plurality of blades 232 are connected to the bent portion 2312. In the axial direction, the end face of the bent portion 2312 away from the straight portion 2311 is flush with the surface of the magnet 240 facing the coil 320.

[0030] Compared with related technologies, the miniature cooling fan provided by this utility model features a hollow coil with a winding groove and a hollow slot on a flexible circuit board. The hollow slot and the winding groove are aligned along the axial direction of the rotating shaft, allowing the first lead extending from the inner winding layer of the coil to extend into the hollow slot and then through the hollow slot to the outer winding layer of the coil on the side away from the winding groove before being soldered to the flexible circuit board. The second lead from the outer winding layer is directly led out and soldered to the flexible circuit board. By leading the first lead out through the winding groove, the coil and the flexible circuit board are ensured to be in close contact with the plane, eliminating the need to clamp the first lead between the flexible circuit board and the coil. This reduces the overall height of the stator assembly composed of the coil and the flexible circuit board, which is beneficial for the miniature cooling fan to be thinner. It also increases the design freedom of the distance between the magnet and the coil, allowing the thickness of the magnet to be increased to increase the driving force and thus increase the fan blade speed to improve heat dissipation efficiency.

[0031] The above description is merely an embodiment of this utility model. It should be noted that those skilled in the art can make improvements without departing from the inventive concept of this utility model, but these improvements all fall within the protection scope of this utility model.

Claims

1. A miniature cooling fan, comprising: An outer casing having a receiving space; A rotor assembly, which is housed within the housing space, includes a rotating shaft rotatably connected to the housing, a bracket mounted on the rotating shaft, fan blades connected to the bracket, and a magnet fixed to the bracket. A stator assembly, comprising a flexible circuit board fixed to the housing and housed within the housing space, and a coil fixed to the flexible circuit board facing the magnet, the coil being spaced apart from the magnet along the axial direction of the rotating shaft, and the coil being a hollow coil; characterized in that, The flexible circuit board has a through-hole groove, and the coil has a winding groove. The through-hole groove and the winding groove are arranged opposite each other along the axial direction. The coil includes an inner winding layer surrounding the winding groove, an outer winding layer opposite to the inner winding layer, a first lead extending from the inner winding layer, and a second lead extending from the outer winding layer and soldered to the flexible circuit board. The first lead extends into the through-hole groove and extends through the through-hole groove to the side of the outer winding layer away from the winding groove before being soldered to the flexible circuit board.

2. The miniature cooling fan according to claim 1, characterized in that, The coil includes an upper surface facing the magnet and a lower surface opposite to the upper surface; along the axial direction, the distance between the upper surface and the flexible circuit board is equal to the distance between the upper surface and the lower surface.

3. The miniature cooling fan according to claim 2, characterized in that, The coil includes a suspension portion located above the hollowed-out groove, and the first lead extends into the hollowed-out groove and is attached to the lower surface of the suspension portion.

4. The miniature cooling fan according to claim 3, characterized in that, The hollow groove includes a first opening opposite to the winding groove and a second opening located on the side of the suspension portion away from the winding groove. The first lead extends through the first opening to the lower surface and extends through the second opening out of the hollow groove before being soldered to the flexible circuit board.

5. The miniature cooling fan according to claim 3, characterized in that, The coils are provided in 3N units, and the slots are provided in 3N units, where N is a natural number greater than 1; the 3N coils are three-phase coils and are equally spaced along the circumference of the rotating shaft.

6. The miniature cooling fan according to claim 3, characterized in that, The flexible circuit board is provided with a first pad for soldering to the first lead and a second pad for soldering to the second lead, and the fan blade is arranged opposite to the first pad and the second pad along the axial direction.

7. The miniature cooling fan according to claim 5, characterized in that, The housing includes a base and a cover plate that cooperate with each other to form the receiving space. The base has a bottom cover that is spaced apart from the cover plate in the axial direction and a side wall that connects the bottom cover and the cover plate. The two ends of the rotating shaft in the axial direction are respectively rotatably connected to the bottom cover and the cover plate. The flexible circuit board is fixed to the surface of the bottom cover facing the cover plate. The cover plate is provided with an air outlet that connects the receiving space to the outside. The side wall is provided with a notch that connects the receiving space to the outside.

8. The miniature cooling fan according to claim 7, characterized in that, The miniature cooling fan also includes a driver chip. The bottom cover has a through hole, and the driver chip is housed in the through hole and fixed to the surface of the flexible circuit board away from the coil. Along the axial direction, the projection of the driver chip is located between two adjacent cutouts.

9. The miniature cooling fan according to claim 7, characterized in that, The bottom cover includes a protruding post extending from the surface facing the cover plate toward the cover plate, the protruding post extending sequentially into the hollow groove and the winding groove, and the projection of the protruding post in the axial direction is rectangular or racetrack-shaped.

10. The miniature cooling fan according to claim 1, characterized in that, The bracket includes a support portion sleeved on the rotating shaft and an extension portion extending from the support portion away from the rotating shaft. The magnet is fixed to the surface of the extension portion facing the coil, and the fan blade is connected to the surface of the extension portion away from the coil. The fan blade includes a connecting portion connected to the extension portion and a plurality of blades connected to the connecting portion and spaced apart. The connecting portion includes a straight portion fixed to the surface of the extension portion away from the coil and a bent portion extending from the straight portion to fit against the surface of the magnet away from the rotating shaft. The plurality of blades are connected to the bent portion. Along the axial direction, the end face of the bent portion away from the straight portion is flush with the surface of the magnet facing the coil.

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