Piezoelectric fan

Abstract

The piezoelectric fan comprises a base plate, wherein a plurality of first through holes penetrating through the base plate are formed in the base plate; the supporting plate is fixed on the base plate; the vibrating diaphragm is fixed on one side, far away from the substrate, of the supporting plate, and the vibrating diaphragm and the substrate are oppositely arranged at an interval; the piezoelectric element is fixed to the vibrating diaphragm and drives the vibrating diaphragm to vibrate in the vibration direction, and the vibrating diaphragm vibrates to push airflow to be discharged through the first through hole; the vibrating diaphragm is circular, the piezoelectric element is annular and is fixed on one side, far away from the supporting plate, of the vibrating diaphragm along the vibration direction, and the vibrating diaphragm comprises a middle part fixed on the supporting plate and a suspension part which extends outwards from the middle part and is arranged at an interval relative to the substrate along the vibration direction; the geometric center of the vibrating diaphragm coincides with the geometric center of the piezoelectric element. The piezoelectric fan is low in power consumption and high in heat dissipation efficiency.

Description

[Technical Field] This invention relates to the field of heat dissipation technology, and more particularly to a piezoelectric fan. [Background Technology] With the development of consumer electronics and semiconductor technology, electronic products are becoming increasingly miniaturized and high-performance, which causes them to generate a lot of heat during operation. If heat cannot be dissipated in time, the internal temperature of the electronic products will rise rapidly, seriously affecting the performance and reliability of the internal electronic components.

[0001] In related technologies, passive cooling is commonly used to reduce the internal temperature of products. However, traditional passive cooling solutions are no longer sufficient to meet the heat dissipation requirements under high heat conditions, and traditional cooling fans are limited by their mechanical structure, making it difficult to achieve miniaturization and thinning.

[0002] Therefore, it is necessary to provide a new piezoelectric fan to solve the above-mentioned technical problems. [Summary of the Invention] The purpose of this invention is to provide a miniaturized, low-power, and low-noise piezoelectric fan.

[0003] To achieve the above objectives, the present invention provides a piezoelectric fan, comprising: A substrate having a plurality of through holes therethrough; A support plate, the support plate being fixed to the base plate; A diaphragm, the diaphragm being fixed to the support plate on the side away from the substrate and spaced apart from the substrate; and A piezoelectric element is fixed to the diaphragm and drives the diaphragm to vibrate along the vibration direction. The vibration of the diaphragm pushes airflow through the first through hole and is discharged. The diaphragm is circular, and the piezoelectric element is annular and fixed to the side of the diaphragm away from the support plate along the vibration direction. The diaphragm includes a middle part fixed to the support plate and a suspension part extending outward from the middle part and spaced apart from the substrate along the vibration direction. The geometric center of the diaphragm coincides with the geometric center of the piezoelectric element.

[0004] Preferably, the projection of the piezoelectric element along the vibration direction partially overlaps with both the middle portion and the suspension portion.

[0005] Preferably, the suspension portion includes a flat plate portion whose plane is perpendicular to the vibration direction and a bent portion extending from the edge of the flat plate portion away from the fixing portion toward the substrate, wherein the extending direction of the bent portion is parallel to the vibration direction.

[0006] Preferably, along the vibration direction, the thickness of the middle portion is greater than the thickness of the flat plate portion.

[0007] Preferably, the support plate includes a fixed portion supporting the middle portion, an extension portion extending outward from the fixed portion, and an edge portion extending outward from the extension portion. The edge portion is fixed to the substrate. The thickness of the extension portion along the vibration direction is less than the thickness of the fixed portion and the edge portion along the vibration direction. The extension portion is spaced apart from the suspension portion and the substrate along the vibration direction. The extension portion is provided with a second through hole extending through it along the vibration direction. The vibration of the suspension portion drives the airflow to exit through the second through hole and the first through hole in sequence.

[0008] Preferably, along the vibration direction, the projected area of ​​the middle portion is smaller than the projected area of ​​the fixed portion, and the projection of the middle portion falls completely within the fixed portion; the support plate further includes a protrusion extending from the surface of the fixed portion toward the diaphragm toward the diaphragm, the middle portion is fixed to the protrusion, and along the vibration direction, the projected area of ​​the protrusion is smaller than the projected area of ​​the middle portion.

[0009] Preferably, the piezoelectric fan further includes a spacer disposed on the edge portion away from the substrate and a cover plate fixed to the spacer on the edge portion away from the substrate. The cover plate is disposed at intervals with the diaphragm along the vibration direction and forms an air intake chamber. The cover plate is provided with an air inlet that passes through it and communicates with the air intake chamber. The air inlet is disposed opposite to the suspension portion along the vibration direction.

[0010] Preferably, the radial distance between the projection of the air inlet along the vibration direction onto the suspension portion and the bent portion is smaller than the radial distance between the air inlet and the middle portion.

[0011] Preferably, along the vibration direction, the air inlet is positioned opposite to the outer edge of the piezoelectric element.

[0012] Preferably, the air inlet is one and is circular, or the air inlet is at least two and is arc-shaped, with at least two air inlets spaced apart and arranged in a circular pattern.

[0013] Compared with related technologies, the piezoelectric fan provided by this invention uses a combination of a ring-shaped piezoelectric element and a circular diaphragm for vibration. The upward movement of the suspended portion of the circular diaphragm reduces gas backflow, resulting in good unidirectional airflow and high energy utilization, thereby increasing gas flow and improving the heat dissipation efficiency of the piezoelectric fan. By adjusting the inner and outer diameters of the ring-shaped piezoelectric element, the characteristic frequency of the diaphragm can be flexibly adjusted, causing a larger displacement of the diaphragm, increasing gas flow, and further improving heat dissipation efficiency. [Attached Image Description] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort, wherein: Figure 1 This is a perspective view of the piezoelectric fan according to Embodiment 1 of the present invention; Figure 2 yes Figure 1 Exploded view of a medium-voltage electric fan; Figure 3 yes Figure 1 Cross-sectional view of a medium-voltage electric fan along line AA; Figure 4 yes Figure 1 Cross-sectional view of a medium-voltage electric fan along line BB; Figure 5 yes Figure 1 Top view of the base plate in a medium-voltage electric fan; Figure 6 yes Figure 1 Top view of the cover plate of a medium-voltage electric fan; Figure 7 This is a cross-sectional schematic diagram of the piezoelectric fan in Embodiment 2 of the present invention; Figure 8 This is a cross-sectional schematic diagram of the piezoelectric fan in Embodiment 3 of the present invention; Figure 9 This is a test diagram of the airflow in the electric fan of the present invention when the air inlet is located at different positions; Figure 10 This is a test diagram showing the airflow rate of a piezoelectric fan using ring-shaped and circular piezoelectric elements.

Detailed Implementation Methods

[0014] like Figure 1-4 As shown, Embodiment 1 of the present invention provides a piezoelectric fan 1000, which includes a substrate 100, a support plate 200 fixed to the substrate 100, a diaphragm 300 fixed to the support plate 200 on the side away from the substrate 100, and a piezoelectric element 400 fixed to the diaphragm 300. Specifically, the diaphragm 300 and the substrate 100 are arranged at a relative interval, and the piezoelectric element 400 drives the diaphragm 300 to vibrate along the vibration direction. The piezoelectric element 400 vibrates under the action of an AC drive signal of a specific frequency, thereby driving the diaphragm 300 to vibrate; it can be understood that the driving frequency of the piezoelectric element 400 is the characteristic frequency of the diaphragm 300, which is usually designed in the ultrasonic frequency range to avoid generating audible noise during vibration.

[0015] like Figure 2 and Figure 5 As shown, the substrate 100 has a plurality of first through holes 110 extending through it, and the vibration of the diaphragm 300 drives airflow to be discharged through the first through holes 110. Specifically, the substrate 100 includes a first base 120 fixedly connected to the support plate 200, a second base 130 circumferentially disposed around the first base 120, and a plurality of connecting beams 140 connecting the first base 120 and the second base 130, the plurality of connecting beams 140 being spaced apart to form the first through holes 110. In this embodiment, the first base 120 is circular, and there are four connecting beams 140, which are equally spaced along the circumference of the first base 120.

[0016] Specifically, the diaphragm 300 is circular, and the piezoelectric element 400 is annular and fixed on the side of the diaphragm 300 away from the support plate 200 along the vibration direction. The geometric center of the diaphragm 300 coincides with the geometric center of the piezoelectric element 400. Furthermore, the diaphragm 300 includes a middle portion 310 fixed to the support plate 200 and a suspension portion 320 extending outward from the middle portion 310 and spaced apart from the substrate 100 along the vibration direction. The diaphragm 300 is circular, so that the suspension portion 320 of the diaphragm 300 deforms like an umbrella under the drive of the piezoelectric element 400. When the suspension portion 320 moves downward, that is, moves toward the substrate 100, it pushes the air between the suspension portion 320 and the substrate 100 to be discharged through the first through hole 110 to generate airflow. When the suspension portion 320 moves upward, that is, moves away from the substrate 100, the airflow moves toward the first through hole 110 at a larger flow rate, while suppressing the backflow of some air below the diaphragm 300. Under the same diaphragm area, it can push a larger volume of air, with good unidirectional airflow effect, high energy utilization rate, increased gas flow rate, and enhanced heat dissipation efficiency of the piezoelectric fan 1000. Optionally, the diaphragm 300 can be made of metal films such as stainless steel, copper, and titanium alloy, or it can be made of non-metallic films with a thickness between 0.02 and 2 mm.

[0017] Furthermore, the piezoelectric element 400 is arranged in a ring shape. Compared with the circular element in the prior art, by adjusting the inner and outer diameters of the ring-shaped piezoelectric element 400, the diaphragm matching different characteristic frequencies can be adjusted, allowing the diaphragm 300 to produce a larger displacement, improving design flexibility, increasing gas flow, and improving heat dissipation efficiency. Specifically, as follows... Figure 10 As shown, when the piezoelectric element 400 is ring-shaped, the piezoelectric fan 1000 generates a larger airflow in the same time period.

[0018] In this embodiment, the projection of the piezoelectric element 400 along the vibration direction partially overlaps with both the middle portion 310 and the suspension portion 320, thereby enhancing the vibration stability of the piezoelectric element 400.

[0019] Furthermore, the suspension portion 320 includes a flat plate portion 321 whose plane is perpendicular to the vibration direction and a bent portion 322 that extends from the edge of the flat plate portion 321 away from the middle portion 310 toward the substrate 100. The extension direction of the bent portion 322 is parallel to the vibration direction. By providing the bent portion 322, it is easier to better expel the air below the suspension portion 320.

[0020] In this embodiment, the thickness of the middle portion 310 is greater than the thickness of the plate portion 321 along the vibration direction, thereby further increasing the distance between the plate portion 320 and the substrate 100, providing more space for the vibration of the suspension portion 320.

[0021] Specifically, the support plate 200 includes a fixing portion 210 supporting the middle portion 310, an extension portion 220 extending outward from the fixing portion 210, and an edge portion 230 extending outward from the extension portion 220. The edge portion 230 is fixed to the substrate 100. Specifically, the fixing portion 210 is disposed between the first base portion 120 of the substrate 100 and the middle portion 310 of the diaphragm 300, and the edge portion 230 is fixed to the second base portion 130 of the substrate 100. The thickness of the extension portion 220 along the vibration direction is less than the thickness of the fixing portion 210 and the edge portion 230 along the vibration direction, such that the extension portion 220 is spaced apart from the suspension portion 320 and the substrate 100 along the vibration direction. The extension portion 220 has a second through hole 221 extending through it along the vibration direction. The vibration of the suspension portion 320 of the diaphragm 300 drives airflow to exit sequentially through the second through hole 221 and the first through hole 110. Figure 4 It can be seen that the second through hole 221 is positioned opposite to the suspension part 320 along the vibration direction.

[0022] Specifically, along the vibration direction, the projected area of ​​the middle portion 310 is smaller than the projected area of ​​the fixed portion 210, and the projection of the middle portion 310 completely falls within the fixed portion 210. The support plate 200 also includes a protrusion 240 extending from the surface of the fixed portion 210 toward the diaphragm 300. The middle portion 310 is fixed to the protrusion 240, and along the vibration direction, the projected area of ​​the protrusion 240 is smaller than the projected area of ​​the middle portion 310. This allows the portion connecting the middle portion 310 to the plate portion 321 to be spaced apart from the fixed portion 210 along the vibration direction, further enhancing the vibration performance of the suspension portion 320 and thus improving the vibration efficiency. The protrusion height of the protrusion 240 is 10-500 μm.

[0023] The piezoelectric fan 1000 further includes a spacer 500 disposed on the side of the edge portion 230 away from the substrate 100, and a cover plate 600 fixed to the side of the spacer 500 away from the edge portion 230. The cover plate 600 is spaced apart from the diaphragm 300 along the vibration direction to form an air inlet chamber 610. An air inlet 620 is provided on the cover plate 600, penetrating through it and communicating with the air inlet chamber 610. The air inlet 620 is disposed opposite to the suspension portion 320 along the vibration direction. In this embodiment, the spacer 500 further includes a first spacer 510 fixed to the edge portion 230 and a second spacer 520 disposed on the side of the first spacer 510 away from the edge portion 230. The cover plate 600 is fixed to the second spacer 520, that is, the second spacer 520 is sandwiched between the first spacer 510 and the cover plate 600. Figures 2 to 4 It can be seen that both the first spacer 510 and the second spacer 520 are annular, and the first spacer 510 and the diaphragm 300 are located on the same plane, that is, the first spacer 510 is arranged in a spacer ring around the diaphragm 300.

[0024] In this embodiment, the air inlet 620 is positioned opposite to the outer edge of the piezoelectric element 400 along the vibration direction.

[0025] Specifically, there may be one air inlet 620 in a circular shape, or there may be at least two air inlets 620, both of which are arc-shaped. At least two air inlets 620 may be spaced apart and arranged in a circular shape. The specific shape and number may be designed according to actual conditions and are not limited here.

[0026] like Figure 7 As shown, in the miniature cooling fan provided in Embodiment 2 of the present invention, the only difference from Embodiment 1 is that the radial distance between the projection of the air inlet 620 on the suspension portion 320 along the vibration direction and the bending portion 322 is smaller than the radial distance between the air inlet 620 and the middle portion 310; by setting the air inlet 620 and the portion of the suspension portion 320 closer to the outside relative to each other, the suspension portion 320 can better form a unidirectional airflow during vibration, increase the flow rate, and thus increase the heat dissipation efficiency.

[0027] like Figure 8 As shown, the only difference between the miniature cooling fan provided in Embodiment 3 of the present invention and Embodiments 1 and 2 is that the radial distance between the projection of the air inlet 620 on the suspension portion 320 along the vibration direction and the bending portion 322 is further reduced. That is, compared with Embodiments 1 and 2, the air inlet 620 is closest to the bending portion 322. By setting the air inlet 620 and the portion of the suspension portion 320 that is closer to the outside, it is easier for the suspension portion 320 to form a unidirectional airflow better during vibration, thereby increasing the flow rate and thus increasing the heat dissipation efficiency.

[0028] like Figure 9As shown, as the air inlet 620 moves outward, the airflow gradually increases. In Embodiment 3, when the projection of the air inlet 620 along the vibration direction is closest to the bend 322, the airflow generated by the piezoelectric fan 1000 is the largest at the same time.

[0029] Compared with related technologies, the piezoelectric fan provided by this invention uses a combination of a ring-shaped piezoelectric element and a circular diaphragm for vibration. The upward movement of the suspended portion of the circular diaphragm reduces gas backflow, resulting in good unidirectional airflow and high energy utilization, thereby increasing gas flow and improving the heat dissipation efficiency of the piezoelectric fan. By adjusting the inner and outer diameters of the ring-shaped piezoelectric element, the characteristic frequency of the diaphragm can be flexibly adjusted, causing a larger displacement of the diaphragm, increasing gas flow, and further improving heat dissipation efficiency. The above description is merely an embodiment of the present invention. It should be noted that those skilled in the art can make improvements without departing from the inventive concept of the present invention, but these improvements all fall within the protection scope of the present invention.

Claims

1. A piezoelectric fan, comprising: A substrate having a plurality of through holes therethrough; A support plate, the support plate being fixed to the base plate; A diaphragm, the diaphragm being fixed to the support plate on the side away from the substrate and spaced apart from the substrate; and A piezoelectric element, fixed to the diaphragm and driving the diaphragm to vibrate along the vibration direction, the vibration of the diaphragm pushing airflow out through the first through hole; characterized in that... The diaphragm is circular, and the piezoelectric element is annular and fixed to the side of the diaphragm away from the support plate along the vibration direction. The diaphragm includes a middle part fixed to the support plate and a suspension part extending outward from the middle part and spaced apart from the substrate along the vibration direction. The geometric center of the diaphragm coincides with the geometric center of the piezoelectric element.

2. The piezoelectric fan according to claim 1, characterized in that, The projection of the piezoelectric element along the vibration direction partially overlaps with both the middle portion and the suspension portion.

3. The piezoelectric fan according to claim 2, characterized in that, The suspension portion includes a flat plate portion whose plane is perpendicular to the vibration direction and a bent portion that extends from the edge of the flat plate portion away from the fixing portion toward the substrate, wherein the extension direction of the bent portion is parallel to the vibration direction.

4. The piezoelectric fan according to claim 3, characterized in that, Along the vibration direction, the thickness of the middle portion is greater than the thickness of the flat plate portion.

5. The piezoelectric fan according to claim 4, characterized in that, The support plate includes a fixed portion supporting the middle portion, an extension portion extending outward from the fixed portion, and an edge portion extending outward from the extension portion. The edge portion is fixed to the substrate. The thickness of the extension portion along the vibration direction is less than the thickness of the fixed portion and the edge portion along the vibration direction. The extension portion is spaced apart from the suspension portion and the substrate along the vibration direction. The extension portion is provided with a second through hole penetrating through it along the vibration direction. The vibration of the suspension portion drives the airflow to exit through the second through hole and the first through hole in sequence.

6. The piezoelectric fan according to claim 5, characterized in that, Along the vibration direction, the projected area of ​​the middle part is smaller than the projected area of ​​the fixed part, and the projection of the middle part falls completely into the fixed part; the support plate also includes a protrusion extending from the surface of the fixed part toward the diaphragm toward the diaphragm, the middle part is fixed to the protrusion, and along the vibration direction, the projected area of ​​the protrusion is smaller than the projected area of ​​the middle part.

7. The piezoelectric fan according to claim 5, characterized in that, The piezoelectric fan further includes a spacer disposed on the edge portion away from the substrate and a cover plate fixed to the spacer on the edge portion away from the substrate. The cover plate is disposed at intervals with the diaphragm along the vibration direction and forms an air intake chamber. The cover plate is provided with an air inlet that passes through it and communicates with the air intake chamber. The air inlet is disposed opposite to the suspension portion along the vibration direction.

8. The piezoelectric fan according to claim 7, characterized in that, The radial distance between the projection of the air inlet along the vibration direction onto the suspension portion and the bending portion is smaller than the radial distance between the air inlet and the middle portion.

9. The piezoelectric fan according to claim 7, characterized in that, Along the vibration direction, the air inlet is positioned opposite to the outer edge of the piezoelectric element.

10. The piezoelectric fan according to claim 7, characterized in that, The air inlet is one and is circular, or the air inlet is at least two and is arc-shaped, with at least two air inlets spaced apart and arranged in a circular pattern.

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