Piezoelectric fan

Abstract

The invention relates to the technical field of heat dissipation, in particular to a piezoelectric fan which comprises an air blowing assembly and a control assembly, the air blowing assembly comprises fan blades and piezoelectric elements arranged on the fan blades, and the piezoelectric elements are attached to the fan blades and used for driving the fan blades to swing in a reciprocating mode; the one-way valve module is attached to the air blowing assembly and comprises a thin film valve which is opened in a one-way mode in the direction away from the air blowing assembly; a groove is formed in the face, facing the thin film valve, of each fan blade. The grooves are formed in the sides, facing the thin film valve, of the fan blades, on one hand, the amplitude of the fan blades is increased, and therefore the air volume is increased, and on the other hand, the air volume and the air pressure are improved; and through the arrangement of the thin film valve which is opened in the one-way direction away from the blowing assembly, backflow can be effectively restrained, compared with the prior art, the flowing direction of airflow can be effectively controlled, the air outlet amount can be increased, the overall airflow output amount is increased, and therefore the heat dissipation efficiency of the piezoelectric fan is improved.

Description

Technical Field

[0001] The invention relates to the technical field of heat dissipation, and in particular to a piezoelectric fan. Background Art

[0002] With the development of increasingly miniaturized electronic devices, the problem of internal heat accumulation has become increasingly prominent. Piezoelectric fans have obvious advantages such as small size and high integration, and have gradually become a research hotspot for micro radiators. Piezoelectric fans are fans that work based on the piezoelectric effect. When the piezoelectric element is stimulated by an electrical signal, the piezoelectric element will undergo periodic deformation, which can cause airflow and generate wind force. However, piezoelectric fans in the prior art still face many challenges.

[0003] In the related art, the core components of a piezoelectric fan usually include a piezoelectric element and a vibration membrane that supports the piezoelectric element, which is usually designed as a thin sheet or plate-like structure. The piezoelectric element drives the vibration membrane to vibrate back and forth, thereby achieving air flow.

[0004] However, in order to adapt to the miniaturization of electronic equipment, the above-mentioned piezoelectric fan needs to sacrifice most of the air volume while ensuring the small size of the piezoelectric fan, and the hot air reflux phenomenon is also very obvious during the reciprocating vibration of the vibration membrane, which leads to low heat dissipation efficiency of the fan. Summary of the invention

[0005] In view of at least one of the above technical problems, the present invention provides a piezoelectric fan which adopts structural improvement to improve heat dissipation efficiency.

[0006] According to a first aspect of the present invention, there is provided a piezoelectric fan, comprising: A blowing assembly, the blowing assembly comprising a fan blade and a piezoelectric element arranged on the fan blade, the piezoelectric element being attached to the fan blade and used for driving the fan blade to swing back and forth; A one-way valve module is arranged in close contact with the blowing assembly, and includes a thin film valve that opens in one direction away from the blowing assembly; Wherein, a groove is provided on a surface of the fan blade facing the film valve.

[0007] In some embodiments of the present invention, the fan blade includes a fixed part and a swinging part, the swinging part is connected to the fixed part and is suspended, and the piezoelectric element is attached to the swinging part to drive the swinging part to swing back and forth in the thickness direction.

[0008] In some embodiments of the present invention, the groove is disposed on the swing portion, and includes a flow suppression groove close to a suspended end of the swing portion.

[0009] In some embodiments of the present invention, the groove further includes an amplifying groove disposed near the fixing portion.

[0010] In some embodiments of the present invention, the one-way valve module further includes an air intake plate, which is sandwiched between the blowing assembly and the film valve, and has an air intake groove arranged toward the fan blade.

[0011] In some embodiments of the present invention, the air inlet groove is arranged corresponding to the swing part, and the depth of the air inlet groove is adapted to the vibration amplitude of the swing part.

[0012] In some embodiments of the present invention, the air inlet groove further has an air inlet hole, and the air inlet hole is arranged opposite to the flow suppression groove.

[0013] In some embodiments of the present invention, the piezoelectric element is a dual-chip piezoelectric ceramic, which is attached to both sides of the fan blade in the thickness direction. The dual-chip piezoelectric ceramic has opposite polarities, so that it expands and contracts in the opposite direction under the action of the electric field.

[0014] In some embodiments of the present invention, the one-way valve module also includes a valve cavity plate arranged on the side of the membrane valve away from the air intake plate, the holes on the membrane valve are staggered with the air intake holes, the membrane valve is attached to one side of the air intake plate, and can be deformed in a direction away from the air intake plate under the action of external force, and the valve cavity plate has an air outlet window for air discharge.

[0015] In some embodiments of the present invention, it also includes a jet plate attached to the side of the valve cavity plate away from the film valve, the jet plate has a jet hole corresponding to the air outlet window, and the cross-sectional area of ​​the jet hole is smaller than the cross-sectional area of ​​the air outlet window.

[0016] In some embodiments of the present invention, it further includes an air outlet plate attached to the jet plate away from the one-way valve module, and the air outlet plate has a lateral air outlet groove connected to the jet hole.

[0017] The beneficial effects of the present invention are as follows: by setting a groove on the side of the fan blade facing the membrane valve, the present invention reduces the thickness of the fan blade, increases the amplitude of the fan blade, and thus increases the air volume; on the other hand, the setting of the groove also increases the air volume and air pressure; and by setting a membrane valve that opens in one direction away from the blowing component, backflow can be effectively suppressed. Compared with the prior art, it can not only effectively control the flow direction of the airflow, but also increase the air output, thereby increasing the overall airflow output, thereby improving the heat dissipation efficiency of the piezoelectric fan. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0019] Figure 1 A schematic diagram of the structure of a piezoelectric fan in an embodiment of the present invention; Figure 2 It is a schematic diagram of the exploded structure of the piezoelectric fan in an embodiment of the present invention; Figure 3 It is a cross-sectional structural schematic diagram of the blowing assembly and the one-way valve module in an embodiment of the present invention; Figure 4 The bimorph structure of the piezoelectric element in the embodiment of the present invention; Figure 5 A schematic diagram of the action structure of a piezoelectric element in an embodiment of the present invention; Figure 6 Schematic diagram of the one-way air outlet structure of the one-way valve module in an embodiment of the present invention; Figure 7 Schematic diagram of the exploded structure of the piezoelectric fan in an embodiment of the present invention.

[0020] Explanation of the reference numerals in the accompanying drawings: 1. Blowing assembly; 11. Fan blade; 11a. Fixed portion; 11b. Swinging portion; 11c. Groove; 11c1. Flow suppression groove; 11c2. Amplification groove; 12. Piezoelectric element; 2. One-way valve module; 21. Membrane valve; 22. Air inlet plate; 22a. Air inlet groove; 22b. Air inlet hole; 23. Valve chamber plate; 23a. Air outlet window; 3. Jet plate; 31. Jet hole; 4. Air outlet plate; 41. Lateral air outlet groove; 5. Support frame; 6. Air inlet cover. DETAILED DESCRIPTION

[0021] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0022] It should be noted that when an element is referred to as being "fixed to" another element, it may be directly on the other element or there may be a central element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. The terms "vertical", "horizontal", "left", "right" and similar expressions used herein are for illustrative purposes only and do not represent the only implementation method.

[0023] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more related listed items.

[0024] In an embodiment of the present invention, the fan blade structure is optimized and the arrangement structure of the piezoelectric element is improved, and a one-way valve module is introduced to improve the air flow transmission efficiency, reduce hot air backflow and improve the heat dissipation capacity. The embodiment of the present invention is introduced in detail below.

[0025] like Figures 1 to 7 The piezoelectric fan shown in the figure includes a blowing component 1 and a one-way valve module 2, as shown in FIG. Figure 1 and Figure 2 As shown in the figure, the blowing assembly 1 includes a fan blade 11 and a piezoelectric element 12 arranged on the fan blade 11, and the piezoelectric element 12 is attached to the fan blade 11 to drive the reciprocating swing of the fan blade 11; it should be pointed out here that in the embodiment of the present invention, the fan blade 11 can be fixed on the bracket at one end, or it can be integrally formed on the metal sheet, and specifically can be adopted as follows Figure 2 The structure shown in the figure makes one end of the fan blade 11 suspended in the air by opening a C-shaped window on the metal sheet; of course, it should be pointed out here that the fan blade 11 can be provided singly or in multiples, and can be provided specifically according to the heat dissipation requirements. The piezoelectric element 12 can be a piezoelectric ceramic sheet, which will expand and contract after being energized, so it can drive the reciprocating swing of the fan blade 11 to generate airflow. By providing the piezoelectric element 12, there is no need for a traditional motor, so the size of the piezoelectric fan can be effectively reduced. Please continue to refer to Figure 2 and Figure 3 In the embodiment of the present invention, the one-way valve module 2 is fitted with the blowing component 1, and includes a film valve 21 that opens in one direction away from the blowing component 1; the one-way valve module 2 here has various forms, wherein the film valve 21 is opened by the air pressure generated when the fan blade 11 is fanned toward the film valve 21, and the film valve 21 has various opening forms, for example, it can be opened by the swing of the valve blade, or by the change of the gap between the valve blade and the hole. In the embodiment of the present invention, in order to further increase the air output and reduce the backflow, as Figure 3 As shown in FIG. 1 , the fan blade 11 has a groove 11c on the side facing the film valve 21. Figure 3 As shown in the figure, through the setting of the groove 11c, on the one hand, the air storage volume at the bottom of the fan blade 11 can be increased, thereby providing a higher wind speed when fanning downward. On the other hand, through the setting of the groove 11c, the wind in the groove 11c can also be blocked, reducing the backflow of air from the swinging end of the fan blade 11, thereby increasing the wind pressure and air volume.

[0026] In the above embodiment, by setting the groove 11c opened on the side of the fan blade 11 facing the membrane valve 21, on the one hand, the thickness of the fan blade 11 is reduced, the amplitude of the fan blade 11 is increased, thereby increasing the air volume, and on the other hand, the setting of the groove 11c also increases the air volume and air pressure; and by setting the membrane valve 21 that opens in one direction away from the blowing component 1, the backflow can be effectively suppressed. Compared with the prior art, it can not only effectively control the flow direction of the airflow, but also increase the air output, thereby increasing the overall airflow output, thereby improving the heat dissipation efficiency of the piezoelectric fan.

[0027] In addition, in the embodiments of this application, please continue to refer to Figure 1 , and also includes a support frame 5 arranged on the side of the blowing component 1 away from the one-way valve module 2 and an air intake cover 6 attached to the support frame 5. The thickness of the support frame 5 is not less than the amplitude of the fan blade 11 on one side, so as to provide space for the vibration above the fan blade 1; the air intake cover 6 has an air intake channel, and technical personnel in this field can choose to intake air from the top or the side as needed; through the arrangement of the support frame 5 and the air intake cover 6, space can be provided for the vibration of the blowing component 1 and the fan blade 11 can be protected.

[0028] Optionally, in some embodiments of the present invention, the fan blade 11 includes a fixed portion 11a and a swing portion 11b, the swing portion 11b is connected to the fixed portion 11a and is suspended, and the piezoelectric element 12 is attached to the swing portion 11b to drive the swing portion 11b to swing back and forth in the thickness direction. Figure 3 As shown in FIG. 1 , in an embodiment of the present invention, the piezoelectric element 12 is attached to the swing portion 11b of the fan blade 11 near the fixed portion 11a so as to Figure 3 Taking the top of the fan blade 11 as an example, when the piezoelectric element 12 contracts, its length becomes shorter, so that the fan blade 11 is subjected to an upward force and the swinging portion 11b of the fan blade 11 is tilted; when the piezoelectric element 12 extends, the swinging portion 11b of the fan blade 11 is bent downward, and when the piezoelectric element 12 is repeatedly stimulated, the fan blade 11 will produce reciprocating vibrations. In an embodiment of the present invention, the driving frequency of the fan blade 11 exceeds 20kHz and is in the ultrasonic stage. There is basically no noise during operation, thereby eliminating noise pollution and providing a quiet heat dissipation solution.

[0029] Optionally, in an embodiment of the present invention, the specific position of the groove 11c is as follows: Figure 3As shown in FIG. 1 , the groove 11c is provided on the swing portion 11b, including a flow suppression groove 11c1 near the suspended end of the swing portion 11b. The flow suppression groove 11c1 here refers to the far end near the swing portion 11b, which is the end away from the fixed portion 11a, and a step is formed at the far end, so that when the fan blade 11 changes from moving upward to moving downward, the outflow of air can be prevented, as shown in FIG. Figure 3 As shown by the curved arrow in the figure, the backflowing gas can form an air curtain, which can further reduce the lateral movement of the airflow along the bottom of the fan blade 11, so that more gas is subjected to the downward pressure of the fan blade 11. Compared with the fan blade 11 structure without the flow suppression groove 11c1, this pressure can provide a greater wind pressure and open the one-way valve module 2 in advance, so that more airflow can flow out from the opened membrane valve 21.

[0030] Optionally, in an embodiment of the present invention, the groove 11c also includes an amplification groove 11c2 disposed near the fixed portion 11a. The amplification groove 11c2 here refers to a groove body disposed near the fixed portion 11a, which can weaken the rigidity of the fan blade 11, thereby increasing the amplitude of the swing portion 11b when swinging. Of course, it should be pointed out here that the flow suppression groove 11c1 disposed near the end of the swing portion 11b also has the effect of increasing the swing amplitude of the swing portion 11b.

[0031] In order to further reduce the gas backflow and increase the heat dissipation efficiency, such as Figure 2 and Figure 3 As shown in , the one-way valve module 2 also includes an air intake plate 22, and the air intake plate 22 is sandwiched between the blowing assembly 1 and the membrane valve 21. The air intake plate 22 has an air intake groove 22a arranged toward the fan blade 11. It should be pointed out here that in the embodiment of the present invention, the air intake groove 22a can introduce more gas into the membrane valve 21 on the one hand, and on the other hand, it also provides a vibration space for the downward swing of the fan blade 11. In the embodiment of the present invention, the air intake groove 22a is arranged corresponding to the swinging part 11b, and the depth of the air intake groove 22a is adapted to the vibration amplitude of the swinging part 11b. As shown in FIG. Figure 3 As shown in , the adaptation here means that the width of the air inlet groove 22a is slightly larger than the width of the swinging portion 11b of the blade 11. Through the setting of this structural form, when the blade 11 is pressed down, more gas can enter the air inlet groove 22a, and then be further squeezed by the blade 11 in the air inlet groove 22a. This squeezing can make the film valve 21 open longer and the ventilation volume larger; further, please continue to refer to Figure 3In an embodiment of the present invention, the air inlet groove 22a also has an air inlet hole 22b, and the air inlet hole 22b is arranged relative to the flow suppression groove 11c1. The relative here means that when the fan blade 11 is in a horizontal state, the width of the flow suppression groove 11c1 is close to the arrangement area of ​​the air inlet hole 22b, or the width of the flow suppression groove 11c1 is slightly larger than the overall width of the air inlet hole 22b. Through the arrangement of this structural form, as described above, the air pressure at the flow suppression groove 11c1 is relatively large. Through the relative arrangement with the air inlet hole 22b, a large airflow can be directly entered into the air inlet hole 22b to open the film valve 21, and the remaining gas enters the air inlet hole 22b during the process of the fan blade 11 and the air inlet groove 22a being close to each other. Through the above arrangement, the film valve 21 can be directly opened by the air pressure under the positive pressure of the flow suppression groove 11c1, and then remain open during the squeezing process of the fan blade 11 and the air inlet groove 22a, thereby further improving the opening time and gas output of the film valve 21. In addition, it should be pointed out here that due to the setting of the one-way valve module 2, not only can the direction of the airflow be effectively controlled, but also the stability of the airflow can be ensured. In each cycle, the regularity and continuity of the airflow are enhanced. For example, when the fan blade 11 changes from downward pressure to upward pressure, due to the action of the one-way valve, the gas will not flow back from the air inlet hole 22b, but will be sucked into the space between the fan blade 11 and the air inlet groove 22a from the outside of the air inlet groove 22a. Through the setting of this structural form, the fan blade 11 can output airflow more evenly and continuously, reducing the fluctuation or instability of the airflow.

[0032] Optionally, in some embodiments of the present invention, in order to further increase the fanning amplitude of the fan blade 11, as Figure 4 and Figure 5 As shown in , the piezoelectric element 12 is a dual-chip piezoelectric ceramic, which is attached to both sides of the fan blade 11 in the thickness direction. The polarities of the dual-chip piezoelectric ceramic are opposite, so that it expands and contracts in the opposite direction under the action of the electric field. In the embodiment of the present invention, by using a dual-chip piezoelectric ceramic, such as Figure 5 As shown in , when the upper piezoelectric ceramic contracts, the lower piezoelectric ceramic stretches, so that the fan blade 11 produces a greater bending effect. In addition, in the embodiment of the present invention, multiple piezoelectric ceramics can be connected in series on the same surface of the fan blade 11 along the expansion and contraction direction of the piezoelectric ceramic, or multiple piezoelectric ceramics can be stacked and arranged in parallel. This structural form can also provide a greater mechanical gain, so that the total displacement is greater than the expansion and contraction displacement of the block, thereby allowing the fan blade 11 to provide a larger swing amplitude, thereby increasing the air output of the piezoelectric fan.

[0033] Regarding the specific structure of the valve sheet module, in some embodiments of the present invention, such as Figure 6As shown in , the one-way valve module 2 also includes a valve cavity plate 23 arranged on the side of the film valve 21 away from the air inlet plate 22, the holes on the film valve 21 are arranged alternately with the air inlet holes 22b, the film valve 21 is attached to one side of the air inlet plate 22, and can be deformed in a direction away from the air inlet plate 22 under the action of external force, and the valve cavity plate 23 has an air outlet window 23a for air discharge. Figure 6 As shown in FIG, the holes on the film valve 21 are staggered with the air inlet holes 22b, so that when the air inlet holes 22b are subjected to the pressure of the fan blades 11 and air is inletted, the film valve 21 can be deformed in a direction away from the air inlet plate 22, as shown in FIG. Figure 6 As shown in the figure above, the film valve 21 bends downward, the gas in the air inlet hole 22b enters the valve chamber plate 23, and is discharged through the air outlet window 23a. When the fan blade 11 bends upward, the film valve 21 resumes the fit with the bottom of the air inlet plate 22, as shown in FIG. Figure 6 As shown in the figure below, the gas cannot flow in the reverse direction; it should be pointed out here that in the embodiment of the present invention, there is no restriction on the number, shape and distribution of the holes on the film valve 21.

[0034] Optionally, in some embodiments of the present invention, in order to further increase the flow rate of the outlet gas, as Figure 7 As shown in , it also includes a jet plate 3 attached to the side of the valve chamber plate 23 away from the film valve 21, and the jet plate 3 has a jet hole 31 corresponding to the air outlet window 23a, and the cross-sectional area of ​​the jet hole 31 is smaller than the cross-sectional area of ​​the air outlet window 23a. Of course, it should be pointed out here that in addition to having a small aperture, the jet hole 31 can also be set to a constricted type, so that the airflow is accelerated in the process of passing through the jet hole 31, thereby improving the wind speed output and heat dissipation efficiency of the fan.

[0035] In the embodiments of the present invention, please continue to refer to Figure 7 , and also includes an outlet plate 4 attached to the jet plate 3 away from the one-way valve module 2, and the outlet plate 4 has a lateral outlet groove 41 connected to the jet hole 31. The lateral outlet groove 41 here refers to the top opening connected to the jet hole 31, and the opening on the side wall of the outlet plate 4, so that the airflow is discharged from the side; through the setting of this structural form, the outlet plate 4 can be directly attached to the heat source, so that the continuous airflow can take away the heat emitted from the heat source, thereby improving the heat dissipation efficiency.

[0036] Those skilled in the art should understand that the present invention is not limited to the above embodiments, and the above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may be subject to various changes and improvements, which are within the scope of the present invention to be protected. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. A piezoelectric fan, characterized in that: include: A blowing assembly, the blowing assembly comprising a fan blade and a piezoelectric element arranged on the fan blade, the piezoelectric element being attached to the fan blade and used for driving the fan blade to swing back and forth; A one-way valve module is arranged in close contact with the blowing assembly, and includes a thin film valve that opens in one direction away from the blowing assembly; Wherein, a groove is provided on a surface of the fan blade facing the film valve.

2. The piezoelectric fan according to claim 1, characterized in that: The fan blade includes a fixed part and a swing part, the swing part is connected to the fixed part and is suspended, and the piezoelectric element is attached to the swing part to drive the swing part to swing back and forth in the thickness direction.

3. The piezoelectric fan according to claim 2, characterized in that: The groove is arranged on the swing part and comprises a flow suppression groove close to a suspended end of the swing part.

4. The piezoelectric fan according to claim 3, characterized in that: The groove further includes an amplifying groove disposed near the fixing portion.

5. The piezoelectric fan according to claim 3, characterized in that: The one-way valve module also includes an air intake plate, which is sandwiched between the blowing assembly and the film valve, and has an air intake groove arranged toward the fan blade.

6. The piezoelectric fan according to claim 5, characterized in that: The air inlet groove is arranged corresponding to the swing part, and the depth of the air inlet groove is adapted to the vibration amplitude of the swing part.

7. The piezoelectric fan according to claim 6, characterized in that: The air inlet groove is also provided with an air inlet hole, and the air inlet hole is arranged opposite to the flow suppression groove.

8. The piezoelectric fan according to claim 3, characterized in that: The piezoelectric element is a dual-chip piezoelectric ceramic, which is respectively attached to the two sides of the fan sheet in the thickness direction. The polarities of the dual-chip piezoelectric ceramic are opposite, so that it expands and contracts in the opposite direction under the action of the electric field.

9. The piezoelectric fan according to claim 7, characterized in that: The one-way valve module also includes a valve cavity plate arranged on the side of the membrane valve away from the air intake plate, the holes on the membrane valve are staggered with the air intake holes, the membrane valve is attached to one side of the air intake plate, and can be deformed in a direction away from the air intake plate under the action of external force, and the valve cavity plate has an air outlet window for air discharge.

10. The piezoelectric fan according to claim 9, characterized in that: It also includes a jet plate attached to the side of the valve cavity plate away from the film valve, the jet plate has a jet hole corresponding to the air outlet window, and the cross-sectional area of ​​the jet hole is smaller than the cross-sectional area of ​​the air outlet window.

11. The piezoelectric fan according to claim 10, characterized in that: It also includes an air outlet plate attached to the jet plate away from the one-way valve module, and the air outlet plate has a lateral air outlet groove connected to the jet hole.

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