Large-amplitude piezoelectric vibrator for micro piezoelectric pump

Abstract

The invention relates to a large-amplitude piezoelectric vibrator for a micro piezoelectric pump, which structurally comprises a first piezoelectric driving layer 31, a second metal substrate layer 32 and a third flexible polymer film layer 33 which are sequentially arranged from top to bottom and are connected through an adhesive, wherein the first piezoelectric driving layer 31 and the third flexible polymer film layer 33 are rectangular, the second metal substrate layer 32 is an isosceles trapezoid, and the symmetry axis of the isosceles trapezoid coincides with the symmetry axis of the two rectangles in the length direction; the area of the upper layer is smaller than that of the lower layer, and the upper layer is completely located within the coverage range of the lower layer; wherein the four edges of the third flexible polymer film layer 33 are fully restrained and clamped by the periphery of the pump body; only one side of the second metal substrate layer 32 is fixed, the other three sides of the second metal substrate layer 32 are free, the fixed sides are narrow sides of the upper bottom of the isosceles trapezoid, and the piezoelectric vibrator with the structure aims at remarkably improving the amplitude of the piezoelectric vibrator and adapting to miniaturization of an electronic device on the premise that the size is not increased.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of piezoelectric driving, in particular to a large-amplitude piezoelectric vibrator for a micro piezoelectric pump. BACKGROUND

[0002] The piezoelectric pump has a wide application prospect in the field of liquid cooling of electronic devices due to its simple structure, small size and convenient processing. As the core component of the piezoelectric pump, the performance of the piezoelectric vibrator directly determines the flow rate and working efficiency of the pump, and the related research and improvement has always been the focus of the field.

[0003] Figure 1 The traditional piezoelectric pump piezoelectric vibrator assembly diagram includes, in turn, a pump cover 1 equipped with a bolt 2, a gasket 4, a piezoelectric vibrator 3, a pump cavity 5, an inlet check valve 61, an outlet check valve 62, a gasket 4 and a pump base 7. The piezoelectric vibrator 3 in it is usually a composite structure of an upper thin circular piezoelectric ceramic and a lower thin circular metal substrate, connected by an adhesive in the middle, and the outer circumference of the piezoelectric vibrator 3 is clamped by the pump cover 1 and the pump chamber 5. When alternating current is applied, the piezoelectric vibrator 3 makes reciprocating motion to realize the pumping function of the pump. However, the center point amplitude of the vibrator of this structure is very small, resulting in small compression rate of the pump cavity and small flow rate, which is difficult to meet the needs of some electronic devices with high cooling efficiency requirements.

[0004] Non-patent document 1 proposes and realizes a multi-channel silicon-based piezoelectric micro-pump with an active piezoelectric valve array, and the piezoelectric vibrator used is a three-layer composite structure composed of a PZT layer, a copper layer and a PDMS layer. When working, the PZT layer deforms, the copper layer acts as the substrate of the PZT layer, which can not only transfer its deformation and output force, but also arch upward or downward with it; the PDMS layer not only ensures the sealing of the pump body, but also effectively improves the amplitude of the vibrator, thereby improving the flow rate of the micro-pump.

[0005] Non-patent document 2 proposes a piezoelectric pump using a piezoelectric ceramic cantilever beam vibrator, which is composed of a cantilever piezoelectric actuator, a hard tube and a silicone biomimetic valve. The fluid driving principle of the pump is: using the inertial force generated in the process of pipe vibration to push the fluid flow. Under the cantilever constraint condition, the displacement amplitude of the vibrator is greater than that under the condition of the whole fixed boundary.

[0006] Non-patent document 3 proposes a piezoelectric cantilever beam vibrator antenna, which has a high stiffness part near the clamping end side and a low stiffness part near the free end side. This variable stiffness beam design helps to improve the amplitude.

[0007] Non-patent document 1: Peng Y H, Wang D H. A novel multi-channel silicon-based piezoelectric micropump with active piezoelectric valve array[J]. Smart Materials and Structures, 2022, 31(7): 075010. Non-patent document 2: Ding J, Cao Y, et al. Development of a novel piezoelectric-actuated inertial pump using bionic valve [J]. Journal of Intelligent Material Systems and Structures, 2021, 32(13): 1571-1580. Non-patent document 3: Chang J L, He Z Z, Xu S P, et al. A High-Q Electric-Mechano-Magnetic Coupled Resonator for ELF / SLF Cross-Medium Magnetic Communication[J]. Advanced Materials, 2023. However, the technologies of non-patent documents 1-3 still have room for improvement in terms of structural design, stiffness matching, and compatibility with micro piezoelectric pumps, and cannot simultaneously achieve significant amplitude improvement, small size, and high integration. SUMMARY

[0008] Therefore, in order to solve the problems in the prior art, the purpose of the present application is to provide a large-amplitude piezoelectric vibrator for a micro piezoelectric pump, which significantly improves the amplitude of the piezoelectric vibrator without increasing the volume, thereby improving the pump cavity volume change rate and flow rate, adapting to the miniaturization of electronic devices, and having the effect of efficient heat dissipation when applied in the field of liquid cooling heat dissipation of electronic devices.

[0009] Specifically, the micro piezoelectric pump uses a large-amplitude piezoelectric vibrator, and the micro piezoelectric pump comprises a pump cover 1 and a pump cavity 5, and the pump cover 1 and the pump cavity 5 clamp the piezoelectric vibrator 3, and the structure of the piezoelectric vibrator 3 comprises: a first layer of piezoelectric driving layer 31, a second layer of metal substrate layer 32 and a third layer of flexible polymer film layer 33 arranged in sequence from top to bottom, and each layer is connected through an adhesive; wherein the first layer of piezoelectric driving layer 31 and the third layer of flexible polymer film layer 33 are rectangular, the second layer of metal substrate layer 32 is isosceles trapezoidal, and the axis of symmetry of the isosceles trapezoidal coincides with the axis of symmetry of the two rectangles along the length direction; the layer area of the first layer of piezoelectric driving layer 31 is smaller than the layer area of the second layer of metal substrate layer 32, and the layer area of the second layer of metal substrate layer 32 is smaller than the layer area of the third layer of flexible polymer film layer 33, and the third layer of flexible polymer film layer 33 completely covers the second layer of metal substrate layer 32, and the second layer of metal substrate layer 32 completely covers the first layer of piezoelectric driving layer 31; wherein the four edges of the third layer of flexible polymer film layer 33 are fully constrained and clamped by the pump cover 1 and the pump cavity 5; the second layer of metal substrate layer 32 is fixed on one side by the pump cover 1 and the pump cavity 5, and the other three sides are free, and the fixed side is the narrow side of the upper base of the isosceles trapezoidal.

[0010] In one embodiment, the single side of the second layer of metal substrate layer 32 is coincident with one fixed side of the third layer of flexible polymer film layer 33.

[0011] In one embodiment, the four edges of the first layer of piezoelectric driving layer 31 are located inside the four edges of the second layer of metal substrate layer 32.

[0012] In one embodiment, the width of the first layer of piezoelectric driving layer 31 is 4-8mm, and the length is 10-15mm; after removing the clamped part, the actual effective vibration area of the second layer of metal substrate layer 32 has an upper base of 5-9mm, a lower base of 7-11mm, and a height of 15-20mm; after removing the clamped part, the actual effective vibration area of the third layer of flexible polymer film layer 33 has a width of 8-12mm and a length of 18-25mm. In one embodiment, the first layer of piezoelectric driving layer 31 is a piezoelectric fiber composite material or a piezoelectric ceramic.

[0013] In one embodiment, the second layer of metal substrate layer 32 is a metal material or a carbon fiber composite material, and the metal material includes one or more of beryllium bronze, aluminum alloy, spring steel and titanium alloy.

[0014] In one embodiment, the third layer of flexible polymer film layer 33 is one or more of polyethylene terephthalate film, polyimide film, silicone film and polydimethylsiloxane film.

[0015] In one of the embodiments, the first piezoelectric driving layer 31 has a bending stiffness smaller than that of the second metal substrate layer 32, and the second metal substrate layer 32 has a bending stiffness smaller than that of the third flexible polymer film layer 33.

[0016] In one of the embodiments, the adhesive is an epoxy resin-based adhesive.

[0017] The present application also protects a micro piezoelectric pump comprising the large-amplitude piezoelectric vibrator for micro piezoelectric pump as described in the present application.

[0018] The present application has the following beneficial effects: The three-layer composite structure and the equivalent cantilever constraint system with one end fixed and the other end free significantly increase the vibrator amplitude, increase the pump cavity volume change rate and flow rate, and help improve the liquid cooling efficiency of electronic devices; the second metal substrate layer is in the shape of an isosceles trapezoid with a narrow fixed end and a wide free end, and the free end has a large area, which further improves the fluid pump cavity volume change rate and optimizes the pump performance; the bending stiffness decreases from the first piezoelectric driving layer to the third flexible polymer film layer, effectively transferring the stress of the piezoelectric driving layer and the strain of the metal substrate layer. The third layer and the second layer are rigid and flexible in cooperation, utilize the stiffness step effect to amplify the vibrator end amplitude again and relieve stress concentration, and enhance the vibrator reliability and service life; the overall structure is exquisite, suitable for micro piezoelectric pumps, consistent with the miniaturization trend of electronic devices, and improves the integration. Experiments show that under the same piezoelectric vibrator area, applied voltage, and first-order bending resonant frequency, the amplitude of the piezoelectric vibrator of the present application can reach 1.9-2.5 times that of the existing piezoelectric vibrator in the idle state. In the working state of the deionized water, the pump cavity volume change rate of the piezoelectric vibrator of the present application is 2-2.5 times that of the existing piezoelectric vibrator, and the flow rate is 1.8-2.2 times. BRIEF DESCRIPTION OF DRAWINGS

[0019] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, the drawings described below are only some embodiments described in the present application, and for those skilled in the art, other drawings can also be obtained from these drawings without creative labor.

[0020] Figure 1 The assembly schematic diagram of the traditional piezoelectric pump piezoelectric vibrator; Figure 2 The overall effect diagram of the micro piezoelectric pump containing the exemplary large-amplitude piezoelectric vibrator of the present application; Figure 3 The A view (top view) of Figure 2 ​Figure 4 This is an assembly diagram of a miniature piezoelectric pump containing an exemplary large-amplitude piezoelectric vibrator of the present invention.

[0021] In the accompanying drawings, the same or corresponding reference numerals indicate the same or corresponding parts.

[0022] 1-Pump cover; 2-Bolt; 3-Piezoelectric vibrator; 4-Washer; 5-Pump chamber; 61-Inlet check valve; 62-Outlet check valve; 7-Pump base; 31-First piezoelectric driving layer; 32-Second metal substrate layer; 33-Third flexible polymer film layer; 34-Fixed edge of metal substrate layer. Detailed Implementation

[0023] The principles and spirit of the invention will now be described with reference to several exemplary embodiments. It should be understood that these embodiments are given merely to enable those skilled in the art to better understand and implement the invention, and are not intended to limit the scope of the invention in any way. Rather, these embodiments are provided to make this disclosure more thorough and complete, and to fully convey the scope of this disclosure to those skilled in the art.

[0024] This invention provides a specific embodiment of a large-amplitude piezoelectric vibrator for a miniature piezoelectric pump. Figure 2 This is an overall rendering of a miniature piezoelectric pump containing an exemplary large-amplitude piezoelectric vibrator of the present invention. The miniature piezoelectric pump includes a pump cover 1 and a pump chamber 5, with the pump cover 1 and pump chamber 5 holding the piezoelectric vibrator 3. Figure 3 for Figure 2 A-view (top view), such as Figure 3 As shown, the specific structure of the piezoelectric vibrator 3 is as follows: from top to bottom, a first piezoelectric driving layer 31, a second metal substrate layer 32, and a third flexible polymer film layer 33 are arranged sequentially, and the layers are connected by epoxy resin adhesive.

[0025] Specifically, each layer is quadrilateral, with the first piezoelectric driving layer 31 and the third flexible polymer film layer 33 being rectangular, and the second metal substrate layer 32 being an isosceles trapezoid. Figure 2 From the perspective of direction A, the axis of symmetry of the isosceles trapezoid coincides with the axis of symmetry of the two rectangles along their length; the area of ​​the upper layer is smaller than that of the lower layer, and the upper layer is completely covered by the lower layer; that is, the area of ​​the first piezoelectric driving layer 31 is smaller than the area of ​​the second metal substrate layer 32, and the area of ​​the second metal substrate layer 32 is smaller than the area of ​​the third flexible polymer film layer 33, and the third flexible polymer film layer 33 completely covers the second metal substrate layer 32, and the second metal substrate layer 32 completely covers the first piezoelectric driving layer 31.

[0026] Preferably, the four edges of the first piezoelectric driving layer 31 are located inside the four edges of the second metal substrate layer 32, the fixed edge 34 of the second metal substrate layer 32 coincides with one edge of the third flexible polymer film layer 33, and the remaining three edges of the second metal substrate layer 32 are located inside the third flexible polymer film layer 33.

[0027] More specifically, from the perspective of miniaturization, pump cavity volume change rate and flow, the specific dimensions of each layer are as follows: the width of the first piezoelectric driving layer 31 is in the range of 4-8 mm, and the length is in the range of 10-15 mm, preferably 5.5-6.5 mm in width and 11-13 mm in length; after removing the clamped part, the upper bottom of the second metal substrate layer 32 is in the range of 5-9 mm, the lower bottom is in the range of 7-11 mm, and the height is in the range of 15-20 mm, preferably 5.5-6.5 mm in upper bottom, 7.5-8.5 mm in lower bottom, and 16-18 mm in height; after removing the clamped part, the actual effective vibration area of the third flexible polymer film layer 33 is in the range of 8-12 mm in width and 18-25 mm in length, preferably 9-11 mm in width and 19-22 mm in length, and the area ratio of the three is adapted to the above size relationship to ensure that the upper layer is completely covered by the lower layer and the deformation transmission is efficient.

[0028] Preferably, the four edges of the third flexible polymer film layer 33 are fully constrained and clamped by the pump cover 1 and the pump cavity 5, and the four edges of the third flexible polymer film layer 33 are first glued to the pump cover and the pump cavity to ensure air tightness; only one side of the second metal substrate layer 32 is fixed by the pump cover 1 and the pump cavity 5, the fixed edge 34 of the metal substrate layer is the narrow edge of the upper base of the isosceles trapezoid, and the remaining three edges are free, forming an equivalent cantilever constraint system with one end fixed and the other end free, and the fixed edge 34 of the metal substrate layer coincides with one fixed edge of the third flexible polymer film layer 33. At the same time, the overall length of the second metal substrate layer 32 is less than the length of the pump cavity 5, so that the free end does not contact the pump cavity wall. The stiffness distribution of the traditional rectangular cantilever beam is uniform, and the deformation is mainly concentrated at the free end, with limited amplification effect; while the isosceles trapezoidal structure gradually reduces the bending stiffness of the second metal substrate layer 32 from the free end to the fixed end, achieving the effect of low stiffness at the narrow end and high stiffness at the wide end. Since the clamped end is the narrow end, a greater amplitude can be obtained when the metal substrate layer 32 is subjected to the same bending moment. At the same time, the effective driving area of the free end remains unchanged, directly improving the pump cavity volume change rate, thereby being able to push more fluid, solving the problem of small flow caused by insufficient amplitude of the traditional vibrator.

[0029] Further, by fixing the narrow edge of the second metal substrate layer 32, the suppression of vibration by the constraint area can be reduced, and the symmetrical structure of the isosceles trapezoid can ensure uniform force transmission during vibration, avoiding local fatigue damage caused by uneven stress distribution, and balancing large amplitude and structural reliability.

[0030] Preferably, the third layer of flexible polymer film layer 33 is fully constrained on four sides, both to ensure the air tightness of the pump cavity 5 and to provide a stable fixed base for the overall structure. The fixed edge 34 of the metal substrate layer coincides with the fixed edge of the third layer of flexible polymer film layer 33, so that the constraint point of the cantilever beam is consistent with the fixed point of the bottom sealing structure. When vibrating, the deformation of the second layer of metal substrate layer 32 is based on the fixed edge, and the third layer of flexible polymer film layer 33 transmits the stress and strain of the second layer of metal substrate layer 32 through epoxy resin. The gap between the "quasi-free end" of the metal substrate layer 32 and the pump wall acts as a soft beam, while the metal substrate layer 32 acts as a hard beam, further amplifying the amplitude at the soft beam using the stiffness step effect.

[0031] Specifically, from the perspective of performance matching, the bending stiffness of the first piezoelectric driving layer 31, the second metal substrate layer 32, and the third layer of flexible polymer film layer 33 decreases from the first layer to the third layer. The thickness of the first piezoelectric driving layer 31 is 0.2-0.4mm, and the thickness of the second metal substrate layer 32 and the third layer of flexible polymer film layer 33 is between 0.1mm-0.5mm, achieving stiffness gradient through thickness and material property synergy. The third layer of flexible polymer film layer 33 as a low stiffness beam part forms a rigid-flexible collaborative variable stiffness beam effect with the second layer of metal substrate layer 32. The upper layer is smaller than the lower layer and is completely covered, so that the deformation of each layer can be transmitted in order: the active deformation of the first piezoelectric driving layer 31 is transmitted to the second layer of metal substrate layer 32, and the deformation is amplified due to the lower stiffness of the second layer of metal substrate layer 32; the deformation of the second layer of metal substrate layer 32 is transmitted to the third layer of flexible polymer film layer 33, which realizes secondary amplification using its lower stiffness, and finally forms a large amplitude at the free end. If the area between the layers is not matched, such as the upper layer exceeding the lower layer, it will cause local stress concentration, destroy the synergy of deformation, and affect the amplitude output. The driving is conducted from the first layer to the third layer through the contact surface, and if the upper layer area is larger than the lower layer, the excess part is invalid area, which affects the driving transmission efficiency.

[0032] More specifically, when the piezoelectric vibrator 3 provided in the embodiment is connected to an alternating current, the first piezoelectric driving layer 31 deforms under the action of the electric field, and the strain is transmitted through the second layer of metal substrate layer 32. The narrow feature of the clamping end of the second layer of metal substrate layer 32, which is an equivalent cantilever beam structure with an isosceles trapezoidal shape, can further amplify the deformation, and the third layer of flexible polymer film layer 33 deforms cooperatively to relieve stress concentration by virtue of its high flexibility, and finally a large amplitude is generated at the free end.

[0033] Preferably, the second layer metal substrate layer 32 is shorter than the length of the pump cavity 5, which ensures that the free end does not contact the pump cavity wall when vibrating, eliminates mechanical interference, ensures stable operation at large amplitude, maintains the stiffness step structure of the third layer flexible polymer film layer 33 in the length direction to form a hard beam combined with a soft beam, amplifies the end amplitude, and meets the space limitation requirements of the micro piezoelectric pump.

[0034] In the present embodiment, Figure 2 is a whole effect diagram of the micro piezoelectric pump of the present application, Figure 4 is an assembly schematic diagram of the micro piezoelectric pump of the present application, as Figure 2 and Figure 4 shown, the piezoelectric vibrator 3 provided in the present embodiment is installed in the micro piezoelectric pump body. Referring to Figure 4 , the micro piezoelectric pump from left to right is the pump cover 1, the piezoelectric vibrator 3, the outlet check valve 62, the pump cavity 5, the inlet check valve 61 and the pump base 7, the upper side of the pump base 7 is the outlet, and the lower corresponding position is the inlet. When the piezoelectric vibrator 3 reciprocates upward and downward, it cooperates with the working of the inlet check valve 61 and the outlet check valve 62 to realize the pumping of the fluid. Due to the significant increase in the amplitude of the piezoelectric vibrator 3, the volume change rate of the pump cavity is improved, thereby effectively increasing the flow of the pump.

[0035] Preferably, in terms of material selection, the first layer piezoelectric driving layer 31 is selected from piezoelectric fiber composite material or piezoelectric ceramic, both of which have excellent deformation ability and high bending stiffness under electric field driving. The second layer metal substrate layer 32 is selected from metal material or carbon fiber composite material, the metal material includes one or more of beryllium bronze, stainless steel, aluminum alloy, spring steel and other materials, which takes into account the "medium stiffness" characteristics and structural strength, wherein the metal material has good ductility and deformation transmission ability, the carbon fiber composite material is lightweight and the stiffness is adjustable, which can further optimize the dynamic response speed of the vibrator and avoid the cancellation of the deformation energy of the first layer piezoelectric driving layer 31 due to the excessive weight of the substrate. The third layer flexible polymer film layer 33 is selected from one or more of polyethylene terephthalate film, polyimide film, silicone film or polydimethylsiloxane film, which all have low stiffness and high flexibility, thereby producing larger amplitude and being beneficial to relieving stress concentration.

[0036] Further, when the second layer of metal substrate layer 32 is combined in the form of an alloy by selecting multiple metal materials, the alloy composition with different proportions can be selected according to actual needs to achieve the best mechanical properties and piezoelectric adaptability. For example, an alloy made of beryllium bronze and stainless steel retains the good elasticity and fatigue resistance of beryllium bronze, and also improves the overall corrosion resistance and strength of the structure with the help of stainless steel. The alloy of aluminum alloy and spring steel can effectively reduce the weight of the piezoelectric vibrator while ensuring a certain rigidity, thereby reducing energy consumption and improving the working efficiency of the micro piezoelectric pump. In practical applications, by precisely controlling the proportion of each metal material in the alloy and the processing technology, the piezoelectric vibrator 3 can produce a larger and more stable amplitude under the action of an electric field, thereby further optimizing the performance of the piezoelectric pump.

[0037] Further, when the third layer of flexible polymer film layer 33 is combined in the form of a blend film by selecting multiple film materials, the proportion of each film material can be flexibly adjusted according to specific use scenarios and performance requirements. For example, blending polyethylene terephthalate film and polyimide film in a specific ratio can combine the advantages of both, that is, it has good chemical stability and formability of polyethylene terephthalate film, and also has excellent high-temperature resistance and mechanical strength of polyimide film. If silicone film and polydimethylsiloxane film are blended, the elasticity and sealing performance of the film can be further improved on the basis of ensuring flexibility, so as to better adapt to the working environment inside the piezoelectric pump and ensure that the piezoelectric vibrator 3 produces a stable and larger amplitude, thereby improving the overall performance of the piezoelectric pump.

[0038] Preferably, the present application preferably uses an epoxy resin adhesive to connect each layer. The epoxy resin adhesive has high bonding strength and good chemical stability, and more importantly, the elastic modulus of the cured epoxy resin is between the first layer of piezoelectric driving layer 31 and the second layer of metal substrate layer 32, which can reduce the stress reflection caused by hard contact between layers. When the piezoelectric vibrator 3 vibrates at a high frequency, the epoxy resin can buffer the stress between layers through a small amount of deformation, thereby preventing interface peeling caused by long-term vibration and ensuring the service life of the piezoelectric vibrator 3. At the same time, if the first layer of piezoelectric driving layer 31 contains electrodes, the insulation of the epoxy resin can prevent the risk of short circuit between the electrodes.

[0039] To verify the technical effect, Example 1 and Comparative Example 1 are specifically set as follows: Example 1: The first piezoelectric driving layer is selected from PZT-5H piezoelectric ceramic material, and has a rectangular structure with a width of 6 mm, a length of 12 mm and a thickness of 0.3 mm; the second metal substrate layer 32 is selected from beryllium bronze material, and has an isosceles trapezoidal structure with an upper base of 6 mm, a lower base of 8 mm, a height of 17 mm and a thickness of 0.2 mm after removing the clamping part; the isosceles trapezoidal upper base is used as a fixed edge of the metal substrate layer to form an equivalent cantilever structure with one end fixed and the other end free, and the fixed edge coincides with one side of the third layer; the third flexible polymer film layer is selected from polyimide film, and has a rectangular structure with an effective vibration area of 10 mm in width, 20 mm in length and 0.15 mm in thickness after removing the clamping part, is bonded by epoxy resin, and is clamped between the pump cover and the pump cavity to ensure air tightness.

[0040] Comparative Example 1 The vibrator of the comparative example and the third flexible polymer film layer of example 1 have an area of 200 mm², and adopts a traditional ultrasonic piezoelectric vibrator structure, selects piezoelectric ceramic material with the same size and model as example 1, and the substrate is beryllium bronze with the same size as the third layer. The constraint mode adopts the traditional mode of supporting the vibrator around the sealing ring, and is assembled in a micro piezoelectric pump with the same specification as example 1.

[0041] The vibrators of example 1 and comparative example 1 are respectively assembled in a micro piezoelectric pump with the same pump cavity volume of 20 μL, and the test conditions are as follows: Idle state: apply an alternating current with a voltage of 100 Vp-p at the first-order bending resonance frequency, and test the anti-node amplitude of the vibrator; Working state: deionized water is introduced as the working medium, the voltage is kept at 100 Vp-p, and the first-order resonance frequency is kept, the pump cavity volume change rate (i.e. (pump cavity maximum volume-pump cavity minimum volume) / pump cavity maximum volume) and the deionized water flow per unit time are tested.

[0042] The performance results are shown in the following table: In summary, under the same piezoelectric vibrator area, applied voltage and first-order bending resonance frequency, the amplitude of the piezoelectric vibrator provided by the present embodiment can reach 2.25 times that of the prior art piezoelectric vibrator in the idle state; in the working state of introducing deionized water, the pump cavity volume change rate of the piezoelectric vibrator provided by the present embodiment is 2.3 times that of the prior art piezoelectric vibrator, and the flow rate is 1.9 times. Thus, the amplitude of the piezoelectric vibrator is significantly improved without increasing the volume.

[0043] It will be obvious to a person skilled in the art that the application is not limited to the details of the foregoing exemplary embodiments and can be implemented in other concrete forms without departing from the spirit or essential characteristics of the application. The embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the application being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein. No reference signs in the claims should be considered as limiting the scope of the claims to the identity of the reference signs therein.

[0044] Furthermore, it should be understood that although the description is made on the basis of the embodiments, not every embodiment contains only one independent technical solution, and the description of the specification is only for the sake of clarity, and those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that those skilled in the art can understand.

Claims

1. A large-amplitude piezoelectric vibrator for a micro piezoelectric pump comprising a pump cover (1) and a pump cavity (5) that sandwich the piezoelectric vibrator (3), characterized in that, The structure of the piezoelectric vibrator (3) comprises: a first layer of piezoelectric driving layer (31), a second layer of metal substrate layer (32), and a third layer of flexible polymer film layer (33) arranged in turn from top to bottom, each layer being connected by an adhesive; wherein the first layer of piezoelectric driving layer (31) and the third layer of flexible polymer film layer (33) are rectangular, the second layer of metal substrate layer (32) is isosceles trapezoidal, the axis of symmetry of the isosceles trapezoidal coincides with the axis of symmetry of the two rectangles along the length direction; the layer area of the first layer of piezoelectric driving layer (31) is smaller than the layer area of the second layer of metal substrate layer (32), and the layer area of the second layer of metal substrate layer (32) is smaller than the layer area of the third layer of flexible polymer film layer (33), and the third layer of flexible polymer film layer (33) completely covers the second layer of metal substrate layer (32), and the second layer of metal substrate layer (32) completely covers the first layer of piezoelectric driving layer (31); wherein the four sides of the third layer of flexible polymer film layer (33) are fully constrained and clamped by the pump cover (1) and the pump cavity (5); the second layer of metal substrate layer (32) is fixed by the pump cover (1) and the pump cavity (5) on only one side, and the other three sides are free, and the fixed side is the narrow side of the upper base of the isosceles trapezoidal.

2. The large amplitude piezoelectric vibrator for a micro piezoelectric pump according to claim 1, wherein The one side of the second layer of metal substrate layer (32) fixed on one side coincides with one fixed side of the third layer of flexible polymer film layer (33).

3. The large amplitude piezoelectric vibrator for a micro piezoelectric pump according to claim 1, wherein The four sides of the first layer of piezoelectric driving layer (31) are all located inside the four sides of the second layer of metal substrate layer (32).

4. The large amplitude piezoelectric vibrator for a micro piezoelectric pump according to claim 1, characterized by The width of the first layer of piezoelectric driving layer (31) is 4-8mm, and the length is 10-15mm; after removing the clamped part, the actual effective vibration area of the second layer of metal substrate layer (32) has an upper base of 5-9mm, a lower base of 7-11mm, and a height of 15-20mm; after removing the clamped part, the actual effective vibration area of the third layer of flexible polymer film layer (33) has a width of 8-12mm and a length of 18-25mm.

5. The large amplitude piezoelectric vibrator for micro piezoelectric pumps according to claim 1, wherein The first layer of piezoelectric driving layer (31) is a piezoelectric fiber composite material or a piezoelectric ceramic.

6. The large amplitude piezoelectric vibrator for a micro piezoelectric pump according to claim 1, wherein The second layer of metal substrate layer (32) is a metal material or a carbon fiber composite material, and the metal material includes one or more of beryllium bronze, aluminum alloy, spring steel, and titanium alloy.

7. The piezoelectric resonator according to claim 1, wherein The third layer of flexible polymer film layer (33) is one or more of polyethylene terephthalate film, polyimide film, silicone film, and polydimethylsiloxane film.

8. The large amplitude piezoelectric vibrator for a micro piezoelectric pump according to claim 1, wherein The bending stiffness of the first layer of piezoelectric driving layer (31) is smaller than that of the second layer of metal substrate layer (32), and the bending stiffness of the second layer of metal substrate layer (32) is smaller than that of the third layer of flexible polymer film layer (33).

9. The large amplitude piezoelectric vibrator for a micro piezoelectric pump according to claim 1, wherein The adhesive is an epoxy resin-based adhesive.

10. A micro piezoelectric pump comprising the large-amplitude piezoelectric vibrator for a micro piezoelectric pump according to any one of claims 1 to 9.

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