Small resonant piezoelectric stack pump

Abstract

The invention discloses a small resonant piezoelectric stack pump which comprises a diaphragm pump and a piezoelectric driving mechanism. The piezoelectric driving mechanism comprises a reverse-phase amplification rod, a piezoelectric stack and an elastic beam. The anti-phase amplification rod is composed of a fixed beam, a vertical beam, a driving arm, a flexible hinge, a fixed flat plate and a boss. The piezoelectric stack is clamped and fixed on the power side of the reverse amplification rod through the fixed flat plate and the fixed beam; the diaphragm pump comprises a pump cavity, a one-way valve and an inlet and outlet flow channel and is fixed to the resistance side of a driving arm of the piezoelectric driving mechanism through an elastic beam and a screw. According to the invention, through adoption of the elastic beam, resonance driving of the piezoelectric stack in a relatively low frequency range can be realized, and the driving displacement of the piezoelectric stack is greatly improved; the working mode of the piezoelectric driving mechanism is a first-order resonance mode, and the piezoelectric driving mechanism has the advantages of being high in mechanical quality factor, high in driving performance, small in structure and good in working reliability.

Description

Technical Field

[0001] The present invention belongs to the technical field of piezoelectric pumps, and particularly relates to a small resonant piezoelectric stack pump. Background Art

[0002] A piezoelectric pump is a commonly used micro pump. It uses the inverse piezoelectric effect of piezoelectric materials to cause the piezoelectric vibrator to generate mechanical deformation, driving the pump chamber to change its volume, thereby realizing the function of fluid pumping. Piezoelectric pumps have the advantages of compact structure, high power density, fast response speed, high control accuracy, and no electromagnetic interference, and show broad application prospects in the fields of aerospace, robotic systems, automobiles, microelectromechanical engineering, chemical analysis, biomedicine, etc.

[0003] According to the type of driver, piezoelectric pumps can be divided into wafer-driven piezoelectric pumps and stack-driven piezoelectric pumps. Wafer-driven piezoelectric pumps often adopt an integrated structure, that is, the piezoelectric wafer driver is fixedly connected to the diaphragm pump chamber to form an integral pump body, which has the characteristics of compact volume, low cost, and is suitable for miniaturized application scenarios. However, since the piezoelectric wafer is fixed around its perimeter, its deformation amplitude is mechanically constrained, and the output flow rate and back pressure of this type of piezoelectric pump are limited, and the load sensitivity is high.

[0004] Stack-driven piezoelectric pumps have the potential for high output performance due to the characteristics of large output force, fast response speed, and high power density of piezoelectric stack drivers. However, the output displacement of the piezoelectric stack is small, the stiffness is large, and the resonant frequency is high, which cannot effectively match the input impedance of the diaphragm pump. It is often necessary to cooperate with a displacement amplification mechanism or a resonant drive mode to overcome the problem of its inherent insufficient output displacement. The introduction of the displacement amplification mechanism will increase the overall structural complexity of the piezoelectric stack pump and is difficult to meet the miniaturization requirements; moreover, the resonant frequency of the displacement amplification type piezoelectric stack pump is affected by the coupling of the displacement amplification multiple, structural dimensions, and material parameters, making the design difficult. Summary of the Invention

[0005] In order to solve the problems that it is difficult to miniaturize due to the addition of a displacement amplification mechanism in a piezoelectric stack pump and the difficulty in designing the resonant frequency of a displacement amplification type piezoelectric stack pump, the present invention provides a small resonant piezoelectric stack pump.

[0006] To solve the above technical problems, a technical solution adopted by the present invention is:

[0007] A small resonant piezoelectric stack pump, characterized in that it includes a piezoelectric drive mechanism and a diaphragm pump;

[0008] The piezoelectric drive mechanism includes an inverting amplification rod, a piezoelectric stack, and an elastic beam. The inverting amplification rod has an "I" - shaped structure, including a vertical beam, a fixed beam connected to one end of the vertical beam, and a driving arm connected to the other end of the vertical beam;

[0009] One end of the piezoelectric stack and the pump body of the diaphragm pump are respectively located on both sides of the vertical beam and fixedly connected to the fixed beam. The power end of the driving arm is connected with a fixed flat plate through a flexible hinge. The piezoelectric stack is clamped between the fixed flat plate and the fixed beam. The resistance end of the driving arm is detachably connected with an elastic beam, and the other end of the elastic beam is connected with the pump chamber diaphragm of the diaphragm pump through a connector.

[0010] When an alternating current with a bias voltage is applied to the piezoelectric stack, the piezoelectric stack generates reciprocating telescopic deformation in the height direction, drives the elastic beam to generate reciprocating swing through the driving arm, and makes the pump chamber diaphragm generate elastic vibration deformation.

[0011] When the excitation frequency of the AC power supply is the first-order resonance frequency of the piezoelectric driving mechanism, the amplitude of the pump chamber diaphragm reaches the maximum value.

[0012] Further, a stress groove is provided at the junction of the end of the vertical beam and the fixed beam / driving arm.

[0013] Further, the middle part of the elastic beam is a solid structure, a hollow structure or a continuous folding structure.

[0014] Further, a cushion block is provided between the elastic beam and the resistance end of the driving arm.

[0015] Further, at least one end of the piezoelectric stack is provided with an alumina gasket with adjustable thickness.

[0016] Further, the inverting amplifier rod is made of a metal material, and an insulating layer is provided on the surface.

[0017] Further, a kidney-shaped hole is provided inside the resistance end of the driving arm, a threaded hole is provided at the end, and U-shaped notch openings are provided on both side edges.

[0018] Further, the piezoelectric stack is a multi-layer piezoelectric ceramic and is polarized in the thickness direction. The side surface of the piezoelectric stack is connected with an AC power supply with a bias voltage through an electrode lead.

[0019] Further, the height of the piezoelectric stack is 5 - 50 mm, the width is 3 - 20 mm, and the length is 3 - 20 mm.

[0020] Further, the chamber diaphragm pump is a stacked diaphragm pump, including a pump chamber part, a check valve part and an inlet and outlet flow channel part arranged in sequence from top to bottom. The adjacent two parts are hermetically connected. The connector is located inside the pump chamber part, and the central part of the pump chamber diaphragm is clamped inside the connector.

[0021] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0022] (1) The present invention provides a small resonant piezoelectric stack pump. The pump chamber diaphragm is driven to vibrate by a piezoelectric stack driver, thereby realizing the pumping of the fluid in the diaphragm pump. The natural frequency of the piezoelectric driving mechanism is as low as within the operating frequency range of the diaphragm pump, enabling the impedance characteristics of the pump chamber diaphragm and the piezoelectric driving mechanism to be matched. Therefore, during operation, a large-displacement vibration of the driving system can be achieved by applying an external excitation that is substantially the same as the natural frequency of the piezoelectric driving mechanism, enabling the diaphragm pump to pump the fluid normally. Since the system operates at the natural frequency under the working state and has the maximum displacement, which is equivalent to achieving a displacement amplification effect, the working stroke requirement of the pump chamber diaphragm can be satisfied.

[0023] (2) The piezoelectric driving mechanism of the present invention can achieve the resonant driving of the piezoelectric stack driver in a lower frequency range by means of a series elastic beam, greatly improving the driving displacement; and the working mode of the piezoelectric driving mechanism is the first-order resonant mode, which has the advantages of high mechanical quality factor, high driving performance, and good working reliability.

[0024] (3) In the piezoelectric driving mechanism of the present invention, the stiffness of the elastic beam can be designed and adjusted by changing the thickness of the beam, adopting different shapes such as folded beams, and processing materials, etc., and then the first-order resonant frequency of the piezoelectric driving mechanism can be greatly adjusted to facilitate matching with the optimal working frequency of the diaphragm pump, so that the working performance of the piezoelectric pump reaches the best.

[0025] (4) The piezoelectric driving mechanism of the present invention adopts an inverting amplifier rod and an elastic beam, with a compact structure, easy to design and process. It adopts a detachable structure design, has a recyclable piezoelectric driving mechanism and a detachable diaphragm pump, is easy to replace damaged parts, and reduces the use cost. Description of the Drawings

[0026] Figure 1 is a schematic perspective view of the overall structure of the present invention.

[0027] Figure 2 is a schematic cross-sectional view of the overall structure.

[0028] Figure 3 is a schematic structural view of the piezoelectric driving mechanism.

[0029] Figure 4 is an exploded view of the diaphragm pump.

[0030] Figure 5 is a schematic diagram of the deformation mode of the piezoelectric driving mechanism and the working state of the diaphragm pump when the excitation voltage of the driving power supply rises.

[0031] Figure 6 is a schematic diagram of the deformation mode of the piezoelectric driving mechanism and the working state of the diaphragm pump when the excitation voltage of the driving power supply drops.

[0032] Figure 7 It is a schematic diagram of the deformation mode of the piezoelectric drive mechanism and the working state of the diaphragm pump when the excitation frequency of the drive power supply approaches the first-order bending resonance frequency of the piezoelectric drive mechanism and the excitation voltage rises.

[0033] Figure 8 It is a schematic diagram of the deformation mode of the piezoelectric drive mechanism and the working state of the diaphragm pump when the excitation frequency of the drive power supply approaches the first-order bending resonance frequency of the piezoelectric drive mechanism and the excitation voltage drops.

[0034] Figure 9 It is the frequency response curve when the piezoelectric drive mechanism adopts elastic beams of three different structural forms.

[0035] 1. Piezoelectric drive mechanism; 2. Boss; 3. Vertical beam; 4. Inverting amplifier rod; 5. Diaphragm pump; 6. Drive arm; 7. Flexible hinge; 8. Fixed flat plate; 9. Piezoelectric stack; 10. Alumina gasket; 11. Pad; 12. Elastic beam; 13. First screw; 14. Connector; 15. Pump chamber diaphragm; 16. Pump chamber diaphragm pressing plate; 17. Sealing ring; 18. Upper one-way valve plate; 19. Cantilever beam valve; 20. Lower one-way valve plate; 21. Inlet and outlet flow channel plate; 22. Second screw; 23. Third screw; 24. AC power supply. Specific implementation mode

[0036] The following elaborates on the preferred embodiments of the present invention in conjunction with the accompanying drawings, so that the advantages and features of the present invention can be more easily understood by those skilled in the art, thereby making a clearer and more definite definition of the protection scope of the present invention.

[0037] It should be noted that when a component is referred to as being "mounted on" another component, it can be directly on the other component or there can also be an intermediate component. When a component is considered to be "set on" another component, it can be directly set on the other component or there may be an intermediate component at the same time. When a component is considered to be "fixed to" another component, it can be directly fixed to the other component or there may be an intermediate component at the same time.

[0038] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the technical field to which the present invention belongs. The terms used in the description of the present invention in this specification are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "or / and" used herein includes any and all combinations of one or more related listed items.

[0039] See Figures 1 to 3, A small resonant piezoelectric stack pump includes a piezoelectric driving mechanism 1 and a diaphragm pump 5. The piezoelectric driving mechanism 1 includes a piezoelectric stack 9, an inverting amplification rod 4, and an elastic beam 12. The inverting amplification rod 4 has a "work" - shaped structure, is made of metal, and has an insulating layer on its surface, such as being coated with insulating paint on the surface or being anodized to achieve insulation. The waist is a vertical beam 3. The bottom end of the vertical beam 3 is vertically connected to a fixed beam 4, and the top end of the vertical beam 3 is vertically connected to a driving arm 6. Among them, stress grooves are provided at the junction of the bottom end of the vertical beam 3 and the fixed beam 4 and at the junction of the top end of the vertical beam 3 and the driving arm 6, so that the driving arm 6 forms a lever structure at the top end of the vertical beam 3. The part of the driving arm 6 on the left side of the vertical beam 3 is the power arm, and the part on the right side of the vertical beam 3 is the resistance arm. When a rotational torque is applied to the power arm end, the resistance arm end swings up / down correspondingly, thereby realizing the in - phase output of power and the amplification, equal or reduction output of displacement. Four through - holes are provided at both end portions on both sides of the fixed beam 4 for connecting the whole piezoelectric stack pump to an external fixing device.

[0040] A fixed flat plate 8 parallel to the driving arm is arranged below the driving arm, and the middle part of the top surface of the fixed plate 8 is connected to the bottom surface of the driving arm through a flexible hinge 7. In this way, when the fixed flat plate 8 moves vertically up / down, the driving arm can be pushed to swing up / down synchronously around the top end of the vertical beam 3 (the fulcrum of the lever structure) through the flexible hinge 7. The flexible hinge 7 can compensate for the horizontal displacement of the connection position during the swinging process.

[0041] In this embodiment, the piezoelectric stack 9 is a multi - layer piezoelectric ceramic and is polarized along the thickness direction. The height of the piezoelectric stack is 5 - 50 mm, the width is 3 - 20 mm, and the length is 3 - 20 mm. The side surface of the piezoelectric stack 9 is connected to an AC power supply 24 with a bias voltage U1 through an electrode lead. By applying an AC voltage with a certain frequency to the piezoelectric stack 9 through the AC power supply 24, the piezoelectric stack 9 generates reciprocating telescopic deformation along the height direction, thereby driving the fixed flat plate 8 to move up and down reciprocally, providing power for the power arm of the driving arm 6. On one side of the top surface of the fixed beam 4 below the power arm, two bosses 2 parallel to the side surface of the vertical beam 3 are provided. The bottom end of the piezoelectric stack 9 is fixedly embedded between the two bosses 2 to limit the horizontal displacement of the piezoelectric stack 9 in the left - right direction. The piezoelectric stack 9 is clamped between the fixed flat plate 8 and the fixed beam 4 in the vertical direction, so that the piezoelectric stack 9 is fixedly installed in the inverting amplification rod 4, and its height direction is parallel to the vertical height direction of the straight beam 3. Preferably, at least one end of the piezoelectric stack is provided with an alumina gasket 10 with adjustable thickness for adjusting the pre - tightening force when the piezoelectric stack is installed. In this embodiment, an alumina gasket 10 is provided at both the bottom end and the top end of the piezoelectric stack 9.

[0042] A threaded hole is provided at the end of the driving arm, and a first screw 13 is threadedly connected to its bottom. The elastic beam 12 is a long strip plate-like structure made of metal. One end of the elastic beam 12 is fixedly connected to the end of the driving arm by the first screw 13, so that the elastic beam 12 is arranged parallel to the resistance arm and the other end is close to the side where the vertical beam 3 is located. In this way, the elastic beam 12 is completely located directly below the resistance arm, making the overall structure more compact. Preferably, a spacer block 11 is provided between the elastic beam 12 and the resistance end of the driving arm to set the distance between the elastic beam 12 and the resistance arm, so that the other end of the elastic beam 12 has sufficient deformation and swinging space.

[0043] See Figure 4 , the diaphragm pump 5 is a stacked diaphragm pump with variable volume. Its overall structure is divided into three parts, which are, from top to bottom, the pump chamber part, the check valve part, and the inlet and outlet flow channel part. Specifically, the pump chamber part includes an upper pressure plate and a pump chamber diaphragm pressure plate 16 located below the upper pressure plate. Circular through holes are provided at the central positions of both the upper pressure plate and the pump chamber diaphragm pressure plate 16. The circular through hole in the upper pressure plate is used to accommodate the upper half of the connector 14, and the central hole in the pump chamber diaphragm pressure plate 16 serves as the pump chamber for accommodating the lower half of the connector 14. A deformable and vibrating pump chamber diaphragm 15 (kapton film is used in this embodiment) is clamped between the upper pressure plate and the pump chamber diaphragm pressure plate 16. The central part of the pump chamber diaphragm 15 is clamped between the upper half and the lower half of the connector 14. When the connector 14 moves up and down reciprocally, the middle part of the pump chamber diaphragm 15 moves up and down synchronously, and the space volume formed by it and the lower various shells changes periodically, realizing the cyclic switching of the positive and negative pressure states in the pump chamber.

[0044] The check valve part includes an upper check valve plate 18 located below the pump chamber diaphragm pressure plate 16, a lower check valve plate 20 located below the upper check valve plate 18, and a cantilever beam valve 19 located between the upper check valve plate 18 and the lower check valve plate 20. The upper check valve plate 18 is provided with a first square through hole communicating with the pump chamber and located above the negative pressure valve piece and a first circular through hole communicating with the pump chamber and located above the positive pressure valve piece. The lower check valve plate 20 is provided with a second circular through hole located below the positive pressure valve piece and a second square through hole located below the negative pressure valve piece, so that the pump chamber and the two one-way channels in the check valve part form a complete one-way passage.

[0045] The inlet and outlet flow channel part includes an inlet and outlet flow channel plate 21 located below the lower check valve plate 20 and a base plate located below the inlet and outlet flow channel plate 21. A flow inlet channel and a flow outlet channel communicating with the second circular through hole and the second square through hole respectively are provided in the middle of the inlet and outlet flow channel plate 21. Inlet flow threaded holes and outlet flow threaded holes communicating with the flow inlet channel and the flow outlet channel respectively are provided on the side walls, which are used to connect the external inlet flow pipe and the outlet flow pipe respectively.

[0046] Among them, each plate member is a square plate structure of the same size, so that a square column structure is formed after being stacked up and down. Bolt through holes are opened at the four corners of each square plate structure, and threaded holes matching the bolt through holes are opened on the top surface of the fixed beam 4. Four second screws 22 pass through the bolt through holes and are connected to the threaded holes, thereby fixedly connecting the stacked square plates to the fixed beam 4. The airtightness is ensured through a double-sealing design between each functional layer. Specifically, annular grooves are respectively opened on the bottom surface of the pump chamber diaphragm pressing plate 16 and the top surface of the inlet and outlet flow channel plate 21, and sealing rings 17 are arranged in the grooves. When the three parts are tightly connected by the second screws 22, the two sealing rings 17 are compressed and deformed to seal the adjacent two parts. Further, sealing films are arranged at the edge parts between the internal plates of each part, and a sealing film is arranged between the inlet and outlet flow channel plate 21 and the base plate.

[0047] The upper part of the connector 14 at the top of the diaphragm pump 5 is fixedly connected to the inner end of the elastic beam 12 through a third screw 23, so that the diaphragm pump 5 is fixedly installed on the right side inside the inverting amplifier rod 4. To reduce the mass of the resistance arm and facilitate the installation operation of the diaphragm pump 5 inside the inverting amplifier rod 4, a waist-shaped hole is opened inside the resistance end of the driving arm, and U-shaped notches are opened at both side edges. The waist-shaped hole is used for the installation and disassembly of the third screw 23 used for the connection between the flexible beam 12 and the connector 14, and the U-shaped hole is used for the installation and disassembly of the second screw 22 bolts used for the connection between the diaphragm pump 5 and the fixed beam 4.

[0048] The piezoelectric stack 9 can only generate a vibration displacement of one-thousandth of its own height under the rated AC excitation, and this magnitude cannot directly drive the vibration of the pump chamber diaphragm 15. By introducing the elastic beam 12 structure in the present invention, the system stiffness is significantly reduced, and the first natural frequency of the vibration system is greatly adjusted to the working frequency band of the diaphragm pump 5. When the excitation frequency of the AC power supply matches or approaches this first natural frequency, the system generates a resonance response, and both the piezoelectric drive mechanism and the diaphragm pump 5 work in the resonance state, and the amplitude reaches the maximum value, so that the pump chamber diaphragm 15 obtains the maximum displacement. This design breakthrough not only solves the driving frequency matching problem existing in the prior art, but also converts the originally ineffective micron-level displacement into an effective mechanical motion that can drive the pump chamber diaphragm 15 through the resonance amplification effect.

[0049] The working principle of the piezoelectric stack pump of the present invention is specifically as follows:

[0050] See Figure 2 、 Figure 5 and Figure 6, when an AC power supply 24 with a bias voltage is applied to the piezoelectric stack 9, the piezoelectric stack 9 generates reciprocating telescopic deformation in the height direction. This deformation is transmitted through the fixed plate 8 and the flexible hinge 7, driving the power arm and the elastic beam 12 connected thereto to swing reciprocally. Since the bottom of the diaphragm pump 5 is fixed inside the inverting amplifier rod 4 and the connector 14 inside the top is connected to the elastic beam 12, the cavity diaphragm pump 5 is driven to continuously pump fluid; the swing of the elastic beam 12 can be transmitted to the pump cavity diaphragm 15 through the connector 14, causing the pump cavity diaphragm 15 to generate elastic vibration deformation, and further causing the sealed volume of the pump cavity to change periodically: when the elastic beam 12 pulls the connector 14 to deform the pump cavity diaphragm 15 towards the outside of the pump cavity, the sealed volume of the pump cavity becomes larger and the pressure becomes smaller. Under the action of the internal and external pressure difference, the inlet check valve (negative pressure valve plate) opens and the outlet check valve (positive pressure valve plate) closes, and the fluid flows into the pump cavity from the inflow channel through the inlet check valve, completing the fluid suction process; when the elastic oscillator pushes the connector 14 to deform the pump cavity diaphragm 15 towards the inside of the pump cavity, the sealed volume of the pump cavity becomes smaller and the pressure becomes larger. Under the action of the internal and external pressure difference, the inlet check valve closes and the outlet check valve opens, and the fluid flows out of the pump cavity through the outlet check valve to the outflow channel, completing the fluid discharge process.

[0051] See Figure 5 , when the excitation voltage U1 of the AC power supply 24 rises, the piezoelectric stack 9 elongates in the height direction, the resistance arm swings close to the diaphragm pump 5, and the elastic beam 12 pushes the connector 14 to move towards the inside of the pump cavity. At this time, the diaphragm pump 5 is in the process of discharging fluid.

[0052] See Figure 6 , when the excitation voltage U1 of the AC power supply 24 drops, the piezoelectric stack 9 shortens in the height direction, the resistance arm swings away from the diaphragm pump 5, and the elastic beam 12 pulls the connector 14 to move towards the outside of the pump cavity. At this time, the diaphragm pump 5 is in the process of sucking fluid.

[0053] See Figure 7 and Figure 8 , when the excitation frequency of the AC power supply 24 with a bias voltage approaches the first-order inverting bending resonance frequency of the piezoelectric actuator, that is, when the entire piezoelectric drive mechanism operates in its first-order inverting bending resonance mode, the piezoelectric drive mechanism generates first-order bending deformation, and at the same time the elastic beam 12 swings reciprocally under the action of the piezoelectric stack 9, thereby increasing the up and down movement amplitude of the connector 14 connected thereto, further increasing the deformation amplitude of the pump cavity diaphragm 15, and finally improving the output performance of the diaphragm pump 5.

[0054] Mechanical impedance matching is achieved by adjusting the thickness and shape of the elastic beam 12. See Figure 9, which shows schematic diagrams of three structural examples of the elastic beam 12. From right to left, the middle part of the elastic beam 12 is a solid structure, a hollow structure, and a continuous folded structure. The oscillator system adopts the design of using the inverting amplifier rod 4 to fix the elastic beam 12, and the resonant frequency of the piezoelectric drive mechanism can be made consistent with the resonant frequency of the check valve used in the cavity diaphragm pump 5 by adjusting the structure of the elastic beam 12. When the piezoelectric stack pump operates at this resonant frequency, both the piezoelectric drive mechanism and the check valve reach the optimal operating state. Specifically: (a) The first example adopts a straight beam structure (such as the structure shown in the rightmost position in Figure 9 ), the middle part of the elastic beam 12 is a solid structure, and the resonant frequency of the piezoelectric actuator is directly regulated by changing the beam thickness; (b) In the second example, a hollow hole is designed in the middle of the elastic beam 12 (such as the structure shown in the middle position in Figure 9 ), and the coordinated adjustment of stiffness and resonant frequency is achieved by adjusting the aperture size, while significantly reducing the interference of the driving arm on the oscillator movement; (c) The third example adopts a folded beam structure as the middle part of the elastic beam 12 (such as the structure shown in the leftmost position in Figure 9 ), and this design significantly reduces the system stiffness and resonant frequency through beam folding, thereby optimizing the dynamic characteristics of the drive mechanism.

[0055] The technical features of the above-described embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered to be within the scope described in this specification.

[0056] The above is only the embodiment of the present invention, and thus does not limit the patent scope of the present invention. Any equivalent structural or equivalent process transformation made by using the content of the specification and drawings of the present invention, or directly or indirectly applied in other related technical fields, shall be similarly included in the patent protection scope of the present invention.

Claims

1. A small resonant piezoelectric stack pump, characterized in that: It includes a piezoelectric driving mechanism and a diaphragm pump; The piezoelectric driving mechanism includes an inverting amplification rod, a piezoelectric stack, and an elastic beam. The inverting amplification rod has an "I"-shaped structure, including a vertical beam, a fixed beam connected to one end of the vertical beam, and a driving arm connected to the other end of the vertical beam; One end of the piezoelectric stack and the pump body of the diaphragm pump are respectively located on both sides of the vertical beam and fixedly connected to the fixed beam. The power end of the driving arm is connected with a fixed flat plate through a flexible hinge. The piezoelectric stack is clamped between the fixed flat plate and the fixed beam. The resistance end of the driving arm is detachably connected with an elastic beam, and the other end of the elastic beam is connected with the pump chamber diaphragm of the diaphragm pump through a connector; When an alternating current with a bias voltage is applied to the piezoelectric stack, the piezoelectric stack generates reciprocating telescopic deformation in the height direction, drives the elastic beam to generate reciprocating swing through the driving arm, and makes the pump chamber diaphragm generate elastic vibration deformation; When the excitation frequency of the AC power supply is the first resonance frequency of the piezoelectric driving mechanism, the amplitude of the pump chamber diaphragm reaches the maximum value.

2. The small resonant piezoelectric stack pump according to claim 1, characterized in that: A stress groove is provided at the junction of the end of the vertical beam and the fixed beam / driving arm.

3. The small resonant piezoelectric stack pump according to claim 1, wherein: The middle part of the elastic beam is a solid structure, a hollow structure or a continuous folding structure.

4. The small resonant piezoelectric stack pump according to claim 3, wherein: A spacer is provided between the resistance end of the elastic beam and the driving arm.

5. The small resonant piezoelectric stack pump according to claim 1, characterized in that: At least one end of the piezoelectric stack is provided with an alumina gasket with adjustable thickness.

6. The small resonant piezoelectric stack pump according to claim 1, characterized in that: The inverting amplification rod is made of a metal material, and an insulating layer is provided on the surface.

7. The small resonant piezoelectric stack pump according to claim 1, wherein: A waist-shaped hole is provided inside the resistance end of the driving arm, a threaded hole is provided at the end, and U-shaped notch openings are provided on both side edges.

8. The small resonant piezoelectric stack pump according to any one of claims 1 to 7, characterized in that: The piezoelectric stack is a multi-layer piezoelectric ceramic and is polarized in the thickness direction. The side surface of the piezoelectric stack is connected with an AC power supply with a bias voltage through an electrode lead.

9. The small resonant piezoelectric stack pump according to claim 8, characterized in that: The height of the piezoelectric stack is 5 - 50 mm, the width is 3 - 20 mm, and the length is 3 - 20 mm.

10. The small resonant piezoelectric stack pump according to any one of claims 1 to 7, characterized in that: The chamber diaphragm pump is a laminated diaphragm pump, including a pump chamber part, a check valve part, and an inlet and outlet flow channel part arranged in sequence from top to bottom. Adjacent two parts are hermetically connected. The connector is located inside the pump chamber part, and the central part of the pump chamber diaphragm is clamped inside the connector.

Images