Integrated piezoelectric micropump of longitudinal stacking structure and gas pumping method

Abstract

The invention discloses an integrated piezoelectric micropump of a longitudinal stacking structure and a gas pumping method. The integrated piezoelectric micropump comprises a piezoelectric vibrator assembly, a valve body and more than three pump shells which are sequentially stacked. The pump flow grooves formed in the opposite side faces of every two adjacent pump shells define a pump flow cavity. And the axes of the pump flow chambers are overlapped. And a piezoelectric vibrator assembly is arranged in each pump flow cavity. The input pump shell and the middle pump shell are each internally provided with an air inlet flow channel connected to an input opening of the corresponding pump flow cavity. The middle pump shell and the output pump shell are each internally provided with an air outlet channel connected to an output port of the corresponding pump flow cavity. The main air inlet flow path and the main air outlet flow path which can be expanded in a butt joint mode are arranged between the pump shells, so that a modular integrated structure capable of being longitudinally stacked is constructed, multi-stage parallel flow increasing can be flexibly achieved by increasing or decreasing the number of the middle pump shells, and the pump flow requirements of different use scenes are met.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of piezoelectric gas micropumps, and particularly relates to an integrated piezoelectric micropump with a longitudinal stack structure and a gas pumping method BACKGROUND

[0002] As a typical micro-fluid driving device, a piezoelectric pump usually utilizes the converse piezoelectric effect of a piezoelectric ceramic under an applied electric field to cause a periodic deformation of a vibrator, so as to drive the volume change of a pump cavity and achieve the suction and discharge of fluid. Due to its characteristics of no electromagnetic interference, low running noise, fast response speed, and easy miniaturization of structure, the piezoelectric pump has been widely applied to medical drug delivery devices (such as insulin pumps and breast pumps), micro-electronic device heat dissipation systems, and biochemical detection and analysis fields. However, with higher requirements for the core fluid driving components in thickness, volume and performance stability of portable and wearable devices, the existing piezoelectric pump technology gradually exposes many technical bottlenecks in structural integration, vibration performance and fluid transmission efficiency, which are difficult to balance.

[0003] Firstly, in terms of improving the output flow or negative pressure capacity, the existing piezoelectric pump usually adopts a mode of connecting multiple single-cavity pump bodies in series or parallel through external pipelines to realize performance superposition. This non-integrated scheme relying on external pipeline connection not only significantly increases the overall volume and system complexity, which is contrary to the development trend of miniaturization and high integration, but also easily introduces the risk of air tightness failure in the assembly process. At the same time, the existence of external pipelines makes it difficult for the pump body to form a standardized module, limiting the rapid combination and expansion between different pump units, and making it difficult to flexibly adjust the flow level or realize rapid customization according to different application scenarios.

[0004] Secondly, under the condition of high-frequency silent operation, the existing piezoelectric vibrator structure generally faces the inherent contradiction that amplitude and stiffness cannot be balanced. In order to avoid audible noise, the piezoelectric pump usually needs to work at an ultrasonic frequency of more than 20 kHz, which requires the vibration system to have high overall stiffness. However, the traditional equal-thickness metal substrate vibrator faces a dilemma under this condition: if the metal substrate is thickened as a whole to increase the natural frequency of the system, the vibration displacement will be significantly reduced under the same driving voltage, resulting in a decrease in single pumping volume; if the metal substrate is thinned as a whole to increase the amplitude, stress concentration will easily occur at the edge of the piezoelectric ceramic or the bonding interface during high-frequency vibration, thereby causing ceramic cracks, delamination and even failure, which seriously affects the long-term reliability of the pump body. The existing structure optimization for thinning the vibrator often lacks clear mechanical zoning basis, and the slot position and size often depend on empirical setting, making it difficult to effectively balance between amplitude increase and frequency stability.

[0005] Again, in the pump cavity and internal flow channel design, the existing piezoelectric pump mostly uses flat plate vibrator and simple chamber structure, which lacks the coordinated optimization of vibration mode and fluid behavior. On the one hand, the flat plate vibrator structure limits the effective compression ratio of the pump cavity, so that the dead volume in the chamber is large, which reduces the effective fluid delivery amount per vibration cycle; on the other hand, the inlet and outlet flow channels usually only exist as simple passages, and cannot effectively cooperate with the vibration direction of the vibrator and the pressure change of the chamber, and the fluid passing through the narrow channel at high speed is prone to turbulence, vortex and additional flow resistance, resulting in invalid consumption of driving energy, and the conversion efficiency of electric energy to fluid energy is significantly reduced. In addition, in some schemes that attempt to internally connect multiple chambers, the overflow holes mostly use side wall drilling or additional flow channel structure, which not only has complex processing technology, but also easily introduces new leakage paths and weak structure areas.

[0006] In summary, the existing piezoelectric pump technology is still difficult to balance among high integration, high frequency and large amplitude stable output, and high efficiency fluid transmission. On the one hand, the performance expansion of multiple chambers still highly depends on external pipelines, which restricts the miniaturization and modularization development; on the other hand, the vibrator structure is difficult to meet the requirements of sufficient amplitude and reliability under high frequency conditions, and lacks systematic structural design criteria; at the same time, the pump cavity and flow channel still have obvious optimization space in the overall layout and fluid mechanics performance. Therefore, a new piezoelectric pump structure form is needed to systematically improve the above-mentioned problems in the existing technology from the aspects of overall architecture, vibrator support and flow channel organization, so as to meet the comprehensive needs of modern microfluidic systems for miniaturization, high performance and scalability. SUMMARY

[0007] The purpose of the present application is to provide an integrated piezoelectric micro-pump with a longitudinal stacking structure and a gas pumping method, which solves the above technical problems.

[0008] In a first aspect, the present application provides an integrated piezoelectric micro-pump with a longitudinal stacking structure, which comprises a piezoelectric vibrator assembly, a valve body, and three or more pump housings arranged in sequence, which are an input pump housing, one or more intermediate pump housings, and an output pump housing. The pump flow grooves opened on the opposite sides of the adjacent two pump housings form a pump flow chamber. The axes of each pump flow chamber coincide. Each pump flow chamber is provided with a piezoelectric vibrator assembly. The input port and the output port of the pump flow chamber are provided with a valve body for restricting the unidirectional flow of fluid.

[0009] The input pump housing and the intermediate pump housing are each provided with an inlet flow channel connected to the input port of the corresponding pump flow chamber; the intermediate pump housing and the output pump housing are each provided with an outlet flow channel connected to the output port of the corresponding pump flow chamber; and the inlet flow channels are sequentially butted to form an inlet total flow path. The outlet flow channels are sequentially butted to form an outlet total flow path. The inlet total flow path is connected to a total inlet port in the input pump housing. The outlet total flow path is connected to a total outlet port in the output pump housing.

[0010] As preferred, the opposite side edges of the two adjacent pump housings are provided with mutually matching butt joint structures. The butt joint structures include circumferential ridge structures and circumferential concave structures respectively provided on the opposite side edges of the two adjacent pump housings. The opposite side edges of the two adjacent pump housings are positioned and fitted through the circumferential ridge structures and the circumferential concave structures.

[0011] As preferred, the outer circumferential surface of the pump housing is in a cylindrical shape and is provided with two or more protrusion structures. The gas inlet flow channel and the gas outlet flow channel are respectively arranged in two independent protrusion structures.

[0012] As preferred, the piezoelectric vibrator assembly includes a piezoelectric driving element, a support beam structure and a frequency tuning metal substrate which are sequentially stacked. The support beam structure is provided with a plurality of flow channel series ports which are circumferentially arranged around the piezoelectric driving element. The pump flow chamber is communicated through the flow channel series ports in the regions on both sides of the piezoelectric vibrator assembly. The natural frequency of the piezoelectric vibrator assembly is above 20 kHz by adjusting the thickness of the frequency tuning metal substrate.

[0013] As preferred, the outer circumferential fixed frame of the support beam structure is clamped between the opposite side edges of the corresponding two adjacent pump housings. The outer circumferential edge of the support beam structure is attached to the inner side wall of the pump housing to achieve radial positioning of the piezoelectric vibrator assembly.

[0014] As preferred, the frequency tuning metal substrate is provided with a central thinning groove on the side away from the support beam structure.

[0015] As preferred, the diameter and depth of the central thinning groove are determined by the following process: the amplitude and frequency of the piezoelectric vibrator assembly at a plurality of different diameter residual thickness ratios are obtained through simulation or experiment; in the target frequency range, the diameter residual thickness ratio corresponding to the maximum amplitude is selected as the constraint condition. The diameter and depth of the central thinning groove that satisfies the constraint condition are obtained. The diameter residual thickness ratio is the ratio between the diameter of the central thinning groove and the thickness of the frequency tuning metal substrate at the position of the central thinning groove.

[0016] As preferred, the frequency tuning metal substrate is further provided with an annular edge thinning groove on the side away from the support beam structure.

[0017] As preferred, the valve body includes a sealing layer, a valve flap, a spacer and an open layer which are sequentially stacked and fixed along the flow direction. The sealing layer is provided with a plurality of gas inlet holes. The valve flap is provided with a plurality of flow holes. The spacer is provided with a through groove structure. The open layer is provided with a plurality of gas outlet holes. The flow holes on the valve flap are arranged in a staggered manner with the gas inlet holes on the sealing layer. The flow holes on the valve flap are arranged in an aligned manner with the gas outlet holes on the open layer. The spacer is provided with a limiting part at the center position of the through groove structure. The limiting part and the inner edge of the through groove structure are fixedly connected through a connecting beam.

[0018] Secondly, the present invention provides a pumping method that uses an integrated piezoelectric micropump with a longitudinally stacked structure as described above. The pumping method includes:

[0019] The number of pump units, n, is set according to the target flow rate. The number of pump units, n, increases as the target flow rate increases. An integrated piezoelectric micropump is assembled from one input pump housing, n-1 intermediate pump housings, one output pump housing, n piezoelectric resonator assemblies, and 2n valve bodies.

[0020] The same excitation signal is input to the piezoelectric vibrator assembly in the integrated piezoelectric micropump to drive the piezoelectric vibrator assembly to reciprocate. External fluid is input into each pump chamber through the main air inlet path, and after being pressurized by the corresponding piezoelectric vibrator assembly, it is pumped out from the main outlet after merging through the main air outlet path.

[0021] Compared with the prior art, the present invention has the following significant advantages:

[0022] 1. This invention defines the intermediate pump housing, piezoelectric vibrator assembly, and valve body as standard sub-modules with isomorphic interfaces, and sets up an inlet and outlet main flow path in the pump housing that can be docked and expanded, thereby constructing a vertically stackable modular integrated micropump structure. This structure avoids the risks of volume expansion, increased flow resistance, and airtightness caused by the reliance on external pipelines in traditional piezoelectric pumps. Without the need to redevelop molds, different flow levels can be flexibly configured simply by increasing or decreasing the number of intermediate pump housings, significantly improving the modularity and flow customization capabilities of the product, and meeting the needs of multiple application scenarios for both miniaturization and high performance.

[0023] 2. This invention achieves automatic positioning and rapid assembly between pump housings by setting matching concave and convex surrounding structures on corresponding sides of adjacent pump housings, enabling a plug-and-slot type mating structure during longitudinal stacking. This structure reduces alignment steps and the number of fasteners during assembly, lowers assembly difficulty and human error, and improves assembly efficiency and consistency. It is particularly suitable for mass production and rapid maintenance under multi-module stacking conditions.

[0024] 3. The present invention sets a series flow channel port in the support beam structure of the valved piezoelectric pump, thereby forming a series flow channel inside the pump flow chamber. This eliminates the complex process of traditional series connection by drilling holes in the side wall, reduces the risk of device size and airtightness failure, and due to the flexible connection characteristics of the beam structure, effectively disperses stress concentration, greatly increases fatigue life, and facilitates subsequent parallel or joint assembly of multiple devices. Attached Figure Description

[0025] Figure 1 This is a cross-sectional schematic diagram of the integrated piezoelectric micropump provided in Embodiment 1 of the present invention.

[0026] Figure 2 This is a schematic diagram of the packaging of the integrated piezoelectric micropump provided in Embodiment 1 of the present invention.

[0027] Figure 3 This is a schematic diagram of the cross-sectional structure of the intermediate pump casing in Embodiment 1 of the present invention.

[0028] Figure 4 This is the first exploded schematic diagram of the integrated piezoelectric micropump provided in Embodiment 1 of the present invention.

[0029] Figure 5 This is the second exploded view of the integrated piezoelectric micropump provided in Embodiment 1 of the present invention.

[0030] Figure 6 This is an exploded view of the valve body in Embodiment 1 of the present invention.

[0031] Figure 7 This is an exploded view of the piezoelectric vibrator assembly in Embodiment 1 of the present invention.

[0032] Figure 8 This is a schematic diagram of the structure of the frequency-modulated metal substrate with only a central thinning groove in Embodiment 1 of the present invention.

[0033] Figure 9 This is a schematic diagram of the installation of a frequency-modulated metal substrate with only a central thinning groove in Embodiment 1 of the present invention.

[0034] Figure 10 This is a diagram showing the results of the dimensional optimization analysis of the central thinning groove in Embodiment 1 of the present invention.

[0035] Figure 11 This is a schematic diagram of the structure in Embodiment 1 of the present invention, in which a central thinning groove and an edge thinning groove are simultaneously formed on a frequency-modulated metal substrate.

[0036] Figure 12 This is a schematic diagram of the installation of a frequency-modulated metal substrate with both a central thinning groove and an edge thinning groove in Embodiment 1 of the present invention.

[0037] Figure 13 This is a schematic diagram of the working principle of the integrated piezoelectric micropump in the first half of the cycle provided in Embodiment 1 of the present invention.

[0038] Figure 14 This is a schematic diagram of the working principle of the integrated piezoelectric micropump in the second half of the cycle provided in Embodiment 1 of the present invention.

[0039] Figure 15 This is a cross-sectional schematic diagram of the integrated piezoelectric micropump provided in Embodiment 2 of the present invention.

[0040] Figure 16 This is a cross-sectional schematic diagram of the integrated piezoelectric micropump provided in Embodiment 3 of the present invention.

[0041] Reference numerals: 10, Inlet pump housing; 20, Valve body; 21, Opening layer; 201, Exit port; 22, Spacer; 202, Valve chamber; 23, Valve disc; 203, Flow passage; 24, Sealing layer; 204, Inlet port; 30, Piezoelectric vibrator assembly; 31, Piezoelectric drive element; 32, Support beam structure; 33, Frequency-tuned metal substrate; 301, Flow channel series port; 302, Suspension beam; 303, Central bearing. Part; 304, outer peripheral fixing frame; 330, central thinning groove; 331, edge thinning groove; 40, intermediate pump casing; 402, outlet air passage; 403, inlet air passage; 410, surrounding raised edge structure; 411, surrounding concave structure; 420, protrusion structure; 50, output pump casing; 100, main inlet; 500, main outlet; A, first chamber; B, second chamber; C, third chamber; D, fourth chamber. Detailed Implementation

[0042] The present invention will be further described below with reference to the accompanying drawings.

[0043] Example 1

[0044] like Figure 1 and Figure 2 As shown, an integrated piezoelectric micropump with a vertically stacked structure adopts a modular design for easy assembly and maintenance, forming multiple pumping units connected in parallel internally. The integrated piezoelectric micropump includes two piezoelectric oscillator assemblies 30, four valve bodies 20, and three pump housings assembled vertically in sequence. The pump housings are divided into an input pump housing 10, an intermediate pump housing 40, and an output pump housing 50, which are stacked in sequence. The input pump housing 10 and the output pump housing 50 have the same structure and are centrally symmetrical about the center point of the piezoelectric micropump.

[0045] In this embodiment, as Figure 4 and Figure 5 As shown, there is one intermediate pump housing 40; in some other embodiments, there may be multiple intermediate pump housings 40, which are stacked sequentially. Piezoelectric vibrator assemblies 30 are provided between the input pump housing 10 and the intermediate pump housing 40, and between the intermediate pump housing 40 and the output pump housing 50. Each piezoelectric vibrator assembly 30 corresponds to two valve bodies 20. The two valve bodies 20 are respectively located at the input port and output port of the pump chamber where the corresponding piezoelectric vibrator assembly 30 is located.

[0046] like Figure 1 and Figure 3 As shown, the input pump housing 10 has a main inlet 100 on the side opposite to the intermediate pump housing 40; the input pump housing 10 has a pump flow groove on the side near the intermediate pump housing 40, both sides of the intermediate pump housing 40, and the output pump housing 50 has a main outlet 500 on the side opposite to the intermediate pump housing 40.

[0047] Pump flow channels on opposite sides of adjacent housings are joined together to form a pump flow chamber. Each pump flow chamber has an inlet and an outlet. The inlet of the pump flow chamber is located inside the preceding pump housing. The outlet of the pump flow chamber is located inside the following pump housing. Both the inlet and outlet of the pump flow chamber are equipped with supporting structures. The valve body 20 is fixed to the supporting structures.

[0048] A piezoelectric vibrator assembly 30 is fixed in the pump flow chamber. The outer edge of the piezoelectric vibrator assembly 30 is sandwiched between the opposite sides of two adjacent pump casings.

[0049] The input pump housing 10 is provided with an air inlet channel 403. The intermediate pump housing 40 is provided with independent air inlet channels 403 and air outlet channels 402. The output pump housing 50 is provided with an air outlet channel 402. The input end of the air inlet channel in the input pump housing 10 is connected to the main inlet 100 of the input pump housing 10; the output end of the air outlet channel in the output pump housing 50 is connected to the main outlet 500 of the output pump housing 50.

[0050] The air intake channel 403 in the input pump housing 10 is connected to the air intake channel 403 in the intermediate pump housing 40 to form a main air intake path. The air outlet channel 402 in the output pump housing 50 is connected to the air outlet channel 402 in the intermediate pump housing 40 to form a main air outlet path.

[0051] The input end of the main intake flow path is connected to the main inlet 100 on the input pump housing 10. The output end of the main exhaust flow path is connected to the main outlet 500 on the output pump housing 50. The main intake flow path is connected to the inlet of the corresponding pump chamber in the intermediate pump housing 40 through a branch flow path. The main exhaust flow path is connected to the outlet of the corresponding pump chamber in the intermediate pump housing 40 through a branch flow path.

[0052] In this embodiment, two pump chambers are provided, forming four working chambers separated by the piezoelectric vibrator assembly 30: the input pump housing 10 and the first piezoelectric vibrator assembly 30 enclose to form the first chamber A; the first piezoelectric vibrator assembly 30 and the upper part of the intermediate pump housing 40 enclose to form the second chamber B; the lower part of the intermediate pump housing 40 and the second piezoelectric vibrator assembly 30 enclose to form the third chamber C; and the second piezoelectric vibrator assembly 30 and the output pump housing 50 enclose to form the fourth chamber D. A flow channel serial port 301 is integrated on the piezoelectric vibrator assembly 30, allowing the first chamber A to communicate with the second chamber B, and the third chamber C to communicate with the fourth chamber D.

[0053] like Figure 6As shown, the valve body 20 is a speculative valve used for one-way ventilation. It includes a sealing layer 24, a valve disc 23, a spacer 22, and an opening layer 21 that are stacked and laser-welded together along the ventilation direction.

[0054] The sealing layer 24 serves as a fixed end of the valve body 20 and has multiple air inlets 204 for controlling the direction of fluid flow. When the valve disc 23 is in contact with the sealing layer 24, the valve body 20 is in a closed state. The spacer 22 has a through-slot structure, forming a valve cavity 202 between the open layer 21 and the sealing plate 24. A limiting part is provided at the center of the through-slot structure of the spacer 22. The limiting part is fixed to the inner edge of the through-slot structure by a connecting beam. The limiting part is used to limit the range of motion of the valve disc and prevent damage to the valve disc.

[0055] The valve disc 23 is the core structure of the entire valve body 20, located within the valve cavity 202. The valve disc 23 has multiple flow holes 203. The open layer 21 serves as the other fixed end of the valve body 20, and has multiple air outlets 201 to allow fluid passage. When the valve disc is in contact with the open layer 21, the valve body 20 is in an open state. The flow holes 203 on the valve disc 23 are misaligned with the air inlet 204 on the sealing layer 24. The flow holes 203 on the valve disc 23 are aligned with the air outlets 201 on the open layer 21.

[0056] Under the pressure difference across the valve body 20, the valve disc 23 can move between the open layer 21 and the sealing plate 24, responding to changes in pressure difference and controlling the unidirectional flow of fluid.

[0057] The input pump housing 10 has a surrounding concave structure 411 near the side edge of the intermediate pump housing 40, and the intermediate pump housing 40 has a surrounding convex structure 410 near the side edge of the output pump housing 50. The intermediate pump housing 40 has a surrounding convex structure 410 near the side edge of the input pump housing 10, and the output pump housing 50 has a surrounding convex structure 410 near the side edge of the intermediate pump housing 40. The surrounding concave structure 411 forms a plug-type structure at the bottom of the pump housing 40; the surrounding convex structure 410 forms a slot-type structure at the top of the pump housing 40.

[0058] The shapes of the surrounding concave structure 411 and the surrounding convex structure 410 are matched and can be fitted together. The surrounding concave structure 411 and the surrounding convex structure 410 on opposite sides of two adjacent housings form a mating fit structure. The positioning and installation of the two adjacent housings are achieved by the surrounding convex structure 410 being fitted onto the surrounding concave structure 411.

[0059] This embodiment breaks through the traditional two-piece fixed structure of piezoelectric pumps ("cover-bottom") and redefines a standard submodule. This standard submodule consists of an intermediate pump housing 40, a piezoelectric vibrator assembly 30, and two sets of valve bodies 20. The "interface isomorphism" design allows for the continuous vertical stacking of N "standard submodules" between the input pump housing 10 and the output pump housing 50. For normal flow rates, only one intermediate module is installed (i.e., the dual-vibrator structure in this embodiment); for extremely high output flow rates, 3-5 intermediate modules can be stacked directly to achieve multi-stage parallel flow enhancement. This solution eliminates the need for redeveloping molds; by simply increasing or decreasing the number of intermediate modules, products with different flow rates can be flexibly manufactured on the same production line, achieving true rapid customization.

[0060] The outer peripheral surface of the pump housing is mainly cylindrical and has two or more protrusion structures 420. The main air inlet and outlet flow paths are each located within two protrusion structures 420. The presence of these protrusion structures allows for the configuration of the main air inlet and outlet flow paths without significantly increasing the radial dimension of the pump housing, thus contributing to the miniaturization of the piezoelectric micropump. In this embodiment, each pump housing has three protrusion structures. The addition of one protrusion structure contributes to the stability of circumferential positioning between adjacent pump housings.

[0061] like Figure 8 As shown, the piezoelectric vibrator assembly 30 includes a piezoelectric drive element 31, a support beam structure 32, and a frequency-tuned metal substrate 33. The support beam structure 32 includes an integrally formed outer peripheral fixing frame 304, suspension beams 302, and a central support portion 303. The outer peripheral edge of the central support portion 303 is connected to the inner edge of the outer peripheral fixing frame 304 via multiple suspension beams 302. Each suspension beam 302 is evenly distributed circumferentially along the center of the support beam structure 32. Gaps exist between the outer peripheral fixing frame 304, the central support portion 303, and the suspension beams 302, serving as flow channel connection ports 301.

[0062] The outer peripheral edge of the outer peripheral fixing frame 304 is fitted against the inner wall of the pump housing, thereby radially limiting the piezoelectric vibrator assembly 30. The two sides of the outer peripheral fixing frame 304 are respectively fitted against the opposite sides of two adjacent pump housings, thereby axially limiting the piezoelectric vibrator assembly 30. This ensures that the piezoelectric vibrator assembly 30 is stably clamped and fixed between two adjacent pump housings.

[0063] The piezoelectric drive element 31, the support beam structure 32, and the frequency-modulated metal substrate 33 are sequentially and tightly bonded together with epoxy resin to form an integrated three-layer structure with a total thickness controlled between 1.4 and 1.8 mm, achieving structural miniaturization and functional integration. Among them, the support beam structure 32 is the innovative core carrier, made of 304 stainless steel through laser cutting and precision etching, and has three functions: structural support, amplitude amplification, and flow channel integration, completely breaking through the design limitations of the traditional "single support" of valved pump oscillators.

[0064] In some embodiments, the overall diameter of the supporting beam structure 32 is 23mm to 27mm (preferably 25mm), and the thickness is 0.15mm to 0.3mm (preferably 0.2mm). The diameter of the central bearing portion 303 is 18mm to 19mm, matching the size of the piezoelectric vibrator assembly to ensure that the bonding area of ​​the piezoelectric vibrator is completely located within the central bearing area. Secondly, the flow area is controlled: the total flow area formed by the beam gaps is 3mm². 2 ~15mm 2 This ensures that the fluid flows smoothly from the upper chamber to the lower chamber while providing sufficient structural rigidity; thirdly, the flow channel morphology is optimized: the edges of the support beams are etched or stamped to form a streamlined transition, so as to reduce eddy current losses when the fluid flows through the gaps between the beams.

[0065] In some embodiments, the support beam structure 32 includes, but is not limited to, any of the following forms: first, a cross beam structure: consisting of four beams arranged in a cross shape connecting the outer fixed frame and the inner central structure; second, an I-beam structure: consisting of one main beam and two short beams perpendicular to it, suitable for elliptical or rectangular pump bodies; and third, an annular radial beam structure: consisting of 3-8 beams radiating outward from the center, forming a structure similar to wheel spokes.

[0066] The innovative design of the supporting beam structure 32 is reflected in two major dimensions: "optimization of mechanical performance" and "integration of flow channels". Its specific features and functions are as follows:

[0067] 1. Amplification Structural Design: The support beam structure 32 adopts a composite structure of "outer peripheral fixed frame 304 combined with suspended beam 302". The outer peripheral fixed frame 304 has a main body thickness of 0.2mm, and four suspended beams 302 (0.2mm thick) are evenly distributed along the circumference, forming a mechanical system of "flexible support - rigid transmission". Compared with the traditional flat plate oscillator, the beam structure reduces the stiffness in the vibration direction, so that the small deformation generated by the inverse piezoelectric effect of the piezoelectric drive element 31 is amplified into a macroscopic vibration stroke by the support beam structure 32. Combined with the inertial effect of the frequency-tuned metal substrate 33, the amplitude is increased by more than 20% compared with the traditional structure, and the gas push volume of a single vibration is increased by 10%, directly enhancing the output performance of the air pump.

[0068] 2. Integrated design of the flow channel series port 301: The flow channel series port 301 is opened inside the support beam structure 32 along the suspension beam 302, so that the two chambers on both sides of the piezoelectric vibrator assembly 30 are connected in series. This design completely eliminates the external connecting pipes and independent flow channels required by traditional multi-device series connection, reducing the overall size of the air pump by 5% compared with the traditional series structure, and providing a space basis for multi-device integration.

[0069] 3. Additional benefits derived from innovation: In addition to the core functions of amplitude amplification and flow channel integration, the structural design of the support beam structure 32 also brings multiple performance gains: First, the built-in flow channel avoids the gas retention problem of the external flow channel, which is especially suitable for the precise flow requirements of micro medical devices (such as blood pressure monitors and watches); Second, the outer peripheral fixing frame 304 is located at the edge (outer periphery) and plays a supporting and clamping (fixing) role, and makes the vibration stress evenly distributed, reducing local stress concentration; Third, the suspension beam 302 of the support beam structure 32 can serve as a heat conduction path, quickly dissipating the heat generated by the piezoelectric drive element 31 during operation to the pump housing, avoiding the degradation of piezoelectric performance caused by high temperature.

[0070] In this embodiment, the parameters of each functional layer of the piezoelectric oscillator assembly 30 are designed through coordinated matching: the piezoelectric drive element 31 is selected with a diameter of 18mm and a thickness of 0.4mm, which can generate stable expansion and contraction deformation under high-frequency excitation above 20kHz, providing the core driving force for the oscillator. The central bearing part 303 of the support beam structure 32 is fully fitted with the piezoelectric drive element 31 to ensure efficient transmission of deformation; the frequency-modulated metal substrate 33 is made of 430 stainless steel or titanium alloy, with a diameter of 18mm and a thickness of 0.6mm. By changing the local mass distribution, the resonant frequency of the oscillator is adjusted, so that the resonant frequency of the piezoelectric oscillator assembly 30 is stabilized at 20-23kHz, which is precisely matched with the high-frequency working requirements of the air pump.

[0071] When the frequency-modulated metal substrate 33 in the piezoelectric vibrator assembly 30 is in operation under the boundary condition of peripheral fixed support, its vibration characteristics follow the dynamic laws of plate and shell.

[0072] For a frequency-modulated metal substrate with fixed perimeters, the curvature of the substrate is greatest near its edge. Therefore, this region contributes the majority of the system's elastic potential energy and is the frequency-sensitive area for maintaining the overall high-frequency characteristics. In the central region of the metal substrate, the vibration displacement reaches its maximum value. Therefore, the mass in this region contributes the most to the total kinetic energy of the system and is the amplitude-sensitive area affecting the output amplitude.

[0073] Based on the above principles, this embodiment proposes a partitioned design principle of "thinning the amplitude-sensitive area and maintaining the thickness of the frequency-sensitive area." For the frequency-modulated metal substrate 33, local thinning in the central amplitude-sensitive area can significantly reduce the mass of this region, thereby achieving a larger central amplitude with the same driving energy. Maintaining or increasing the thickness of the main body of the peripheral frequency-sensitive area can maximize the maintenance of high bending stiffness in the edge region, thus "locking in" the core frequency characteristics of the system. This selective thinning fundamentally solves the physical contradiction of the incompatibility between "amplitude and frequency" in traditional global thinning schemes.

[0074] like Figure 8 and Figure 9As shown, the frequency-modulated metal substrate 33 has a central thinning groove 330 on its side away from the supporting beam structure 32. The central thinning groove 330 is circular.

[0075] In some embodiments, to determine the optimal thinning parameters, this embodiment uses a frequency-modulated metal substrate 33 with a diameter of 18 mm and a thickness of 0.6 mm as a basis, and systematically analyzes the geometry of the central thinning groove 330 formed on it. The remaining thickness after thinning cannot be less than 0.2 mm, and the diameter of the thinning groove is smaller than the diameter of the frequency-modulated metal substrate, i.e., it cannot exceed 18 mm. For example... Figure 10 The biaxial relationship between the ratio of the diameter of the thinning groove to the remaining thickness of the region after thinning (i.e., the ratio of diameter to remaining thickness is the abscissa, with a value range of 0 to 90) and the performance indicators of the piezoelectric micropump is shown. Figure 10 In the graph, the left vertical axis represents amplitude (in μm), and the corresponding curve shows an upward trend as the diameter-to-remaining-thickness ratio increases, gradually rising from approximately 11 μm when the diameter-to-remaining-thickness ratio is 0 to a maximum of approximately 25 μm. The right vertical axis represents frequency (in kHz), and the corresponding curve shows a downward trend as the diameter-to-remaining-thickness ratio increases, gradually decreasing from an initial 23 kHz to 13 kHz.

[0076] Depend on Figure 10 It is evident that as the diameter-to-remaining-thickness ratio increases (i.e., the thinned area becomes larger or the remaining thickness becomes thinner), the central stiffness and mass decrease simultaneously, leading to a significant increase in amplitude. However, this is accompanied by a rapid decrease in system stiffness, causing a drop in frequency. To meet the requirement of inaudibility (i.e., the frequency must be ≥20kHz) while simultaneously maximizing the amplitude, a balance point between the two curves needs to be found.

[0077] Figure 10 The data shows that the amplitude and frequency reach their optimal balance when the ratio of the diameter to the remaining thickness on the horizontal axis is approximately 22.5. At this point, the corresponding amplitude on the left vertical axis is approximately 14 μm, and the frequency on the right vertical axis is approximately 20.5 kHz. This data indicates that controlling the ratio of the thinning groove diameter to the remaining thickness to be around 22.5 is the optimal design point for this embodiment. It ensures that the micropump operates in the ultrasonic silent frequency band above 20 kHz, while also achieving a significant amplitude increase (approximately 27%) compared to the unthinned state (diameter-to-remaining-thickness ratio equal to 0, amplitude of 11 μm), thus achieving a perfect synergy between high frequency and large amplitude.

[0078] In some embodiments, in addition to the central thinning groove 330, the frequency-modulated metal substrate 33 also has an edge thinning groove 331. The edge thinning groove 331 is disposed around the outer edge of the frequency-modulated metal substrate 33. The edge thinning groove 331 can increase the output cavity space of the pump flow chamber and enhance the flow.

[0079] likeFigure 9 As shown, the frequency-modulated metal substrate 33 is attached to the lower surface of the central support portion 303. This embodiment provides two optimized slotting schemes. Both slotting structures are designed based on the principle of "precise matching of functional zones". The specific structural features and innovative functions are as follows:

[0080] 1. For example Figure 8 and Figure 9 As shown, the single-groove structure (with only a central thinning groove 330) is used. The groove position is determined through simulation optimization. The thinned and unthinned areas of the frequency-modulated metal substrate 33 precisely correspond to the areas with the greatest amplitude and frequency influence of the piezoelectric oscillator, respectively. Specifically, a circular thinning groove with a diameter of 9mm and a depth of 0.2mm is made in the area with the greatest amplitude influence, reducing the thickness of the area where the central thinning groove of the frequency-modulated metal substrate is located from 0.6mm to 0.4mm. By reducing the local inertial load and amplifying the vibration stroke, the measured amplitude is increased by 27% compared to the ungroove frequency-modulated metal substrate. In the area with the greatest frequency influence, a 0.6mm thickened structure is retained. The high density characteristics of 430 metal are used to improve the local stiffness, stabilizing the oscillator resonant frequency at 20~23kHz, achieving the core goal of "increasing amplitude without sacrificing frequency stability".

[0081] 2. For example Figure 11 and Figure 12 As shown, the dual-groove structure (simultaneously forming a central thinning groove 330 and an edge thinning groove 331): Based on the single-groove structure, a surrounding edge thinning groove with a width of 1mm to 3mm and a depth of 0.1mm to 0.2mm can be formed on the edge of the frequency-modulated metal substrate 33. In this embodiment, a surrounding edge thinning groove 331 with a width of 0.3mm and a depth of 0.2mm is formed on the edge of the frequency-modulated metal substrate, forming a dual-groove layout of "central thinning groove + peripheral thinning groove". The function of the central thinning groove 330 is the same as that of the single groove. The edge thinning groove 331 achieves the following: increasing the enclosed space between the frequency-modulated metal substrate and the support beam, increasing the effective volume of the lower chamber, providing more sufficient buffer space for gas flow, and enhancing the drainage effect.

[0082] The working principle of the integrated piezoelectric micropump provided in this embodiment is as follows:

[0083] This piezoelectric pump uses an external high-frequency drive power supply (output frequency 23kHz, peak-to-peak voltage 60V) to excite the piezoelectric vibrator assembly 30 to generate forced vibration. It utilizes the volume change of the chambers on both sides of the piezoelectric vibrator assembly 30 and the conductivity of the valve body 20 to achieve continuous gas delivery. The specific working process is divided into an intake stage and an exhaust stage.

[0084] like Figure 13As shown, when the drive signal is in the positive half-cycle, the first piezoelectric vibrator assembly 30 bends downward, increasing the volume of the first chamber A and creating a negative pressure inside. The valve body 20 at the pump flow chamber inlet opens under the pressure difference, allowing external gas to flow into the first chamber A from the main inlet 100 through the valve body 20, completing the intake process. Simultaneously, due to the downward bending deformation of the piezoelectric vibrator assembly 30, the volume of the second chamber B decreases, creating a positive pressure inside. The valve body 20 at the pump flow chamber outlet opens, allowing gas to flow through the valve body 20, the outlet air passage 402 of the intermediate pump casing 40, and... The gas exits through the outlet channel 402 of the pump housing and finally exits the housing through the main outlet 500, completing the exhaust process in the second chamber B. At the same time, the second piezoelectric vibrator assembly 30 vibrates downwards in the same way, the third chamber C is under negative pressure, and the fourth chamber D is under positive pressure. The valve body 20 located at the pump flow chamber inlet opens, and the gas enters the housing from the main inlet 100 and simultaneously enters the third chamber C from the inlet channel 403 of the pump housing, the inlet channel 403 of the intermediate housing, and the valve body 20 located at the pump flow chamber inlet, completing the intake process in the third chamber C. The gas in the fourth chamber D is under positive pressure due to the downward bending of the vibrator, and the valve body 20 located at the pump flow chamber outlet opens, allowing the gas to be discharged to the outside through the outlet, completing the exhaust process.

[0085] like Figure 14 As shown, when the drive signal is in the negative half-cycle, the first piezoelectric vibrator assembly 30 bends and deforms upward, the volume of the first chamber A decreases, the internal pressure increases, and the valve body 20 located at the inlet of the pump flow chamber closes under pressure; the volume of the second chamber B increases, the internal pressure decreases, and because the support beam structure 32 of the piezoelectric vibrator assembly 30 integrates the flow channel series port 301, the internal communication between the first chamber A and the second chamber B is realized, and gas flows from the first chamber A into the second chamber B. The first chamber A completes the exhaust process, and the second chamber B completes the intake process. During this stage, the valve body 20 located at the outlet of the pump flow chamber remains closed due to the negative pressure of the second chamber B, and the valve disc 23 tightly adheres to the sealing layer 24, enhancing the sealing effect; similarly, the third chamber C and the fourth chamber D achieve the same working process, with the third chamber C exhausting and the fourth chamber D intake.

[0086] In this embodiment, the flow channel series port 301 on the oscillator body realizes the direct internal series connection from the first chamber A to the second chamber B; at the same time, the first chamber A and the third chamber C form a parallel flow path through the inlet flow channel 403; the second chamber B and the fourth chamber D form a parallel flow path through the outlet flow channel 402; therefore, the first chamber A and the third chamber C simultaneously draw in air, and the second chamber B and the fourth chamber D simultaneously exhaust air, thus forming a highly efficient hybrid topology structure of "intra-unit series pressurization and inter-unit parallel flow enhancement".

[0087] By periodically changing the driving signal, the upper and lower piezoelectric vibrators alternately complete bending deformation, realizing a continuous cycle of intake and exhaust processes. Due to the adoption of a dual-chamber internal series structure based on the flow channel series port 301, the gas can complete the flow between chambers without passing through an external flow channel, significantly reducing flow resistance; at the same time, the thinned area of ​​the grooved vibrator increases the vibration amplitude and increases the single pumping volume, while the thickened area ensures the stability of high-frequency vibration, enabling the air pump to achieve efficient gas delivery in a miniaturized size.

[0088] This embodiment achieves the effect of reducing flow resistance and improving overall output efficiency by constructing a hybrid fluid topology structure of "intra-unit series pressurization and inter-unit parallel flow enhancement" inside the pump body. Specifically, the gas can be pressurized in series within a single pump flow unit without passing through an external connecting flow channel. At the same time, multiple pump flow units work in parallel through the inlet and outlet gas flow paths, effectively reducing turbulence, vortices and dead zone volume, reducing ineffective energy loss, and enabling the integrated piezoelectric micropump to still achieve stable and efficient gas delivery performance under miniaturized size.

[0089] Example 2

[0090] An integrated piezoelectric micropump with a vertically stacked structure is described in this embodiment, which differs from Embodiment 1 only in the number of the intermediate pump housing 40, piezoelectric vibrator assembly 30, and valve body 20. In this embodiment, as shown... Figure 15 As shown, there are two intermediate pump housings 40, forming a triplet structure with three pump flow units inside the integrated piezoelectric micropump. Adjacent pump bodies are tightly fitted together via a mating structure. The inlet ports of the three pump flow chambers form parallel flow paths through a main air inlet path; the outlet ports of the three pump flow chambers also form parallel flow paths through a main air outlet path.

[0091] The fluid topology is as follows: external fluid only needs to be connected to the main inlet 100 of the first pump body, and the fluid will be automatically diverted to the independent intake chambers of the three pump flow units; after the two-stage pressurization inside each pump flow unit, the high-pressure gas merges into the main outlet flow path and is discharged uniformly from the main outlet 500.

[0092] Example 3

[0093] An integrated piezoelectric micropump with a vertically stacked structure is described in this embodiment, which differs from Embodiment 1 only in the number of the intermediate pump housing 40, piezoelectric vibrator assembly 30, and valve body 20. In this embodiment, as shown... Figure 15 As shown, there are three intermediate pump housings 40, forming a quadruple structure with four pump flow units inside the integrated piezoelectric micropump. Adjacent pump bodies are tightly fitted together via a mating structure. The inlet ports of the four pump flow chambers form parallel flow paths through the main air inlet path; the outlet ports of the four pump flow chambers form parallel flow paths through the main air outlet path.

[0094] The fluid topology is as follows: external fluid only needs to be connected to the main inlet 100 of the first pump body, and the fluid will be automatically diverted to the independent suction chambers of the four pump flow units; after the two-stage pressurization inside each pump flow unit, the high-pressure gas merges into the main outlet flow path and is discharged uniformly from the main outlet 500.

[0095] This embodiment supports the external parallel expansion of multiple air pumps by reserving a standardized interface, forming a two-dimensional expansion capability of "internal series connection to enhance performance and external parallel connection to expand output". This design makes the volume of the four-pump unit only 4 times that of a single pump, but increases the flow rate to 3.6 to 3.8 times that of a single pump (considering flow resistance loss), and completely eliminates the complex external hose connections between N pumps, greatly improving assembly efficiency and the airtightness and reliability of the system.

[0096] In some other embodiments, the number of pump flow units in the integrated piezoelectric micropump can be further increased.

Claims

1. An integrated piezoelectric micropump of longitudinal stack structure comprising a piezoelectric vibrator assembly (30) and a valve body (20); characterized in that: Also include three or more pump shell arranged in sequence, respectively, an input pump shell (10), one or more intermediate pump shell (40) and an output pump shell (50); the pump flow groove set on the opposite side of two adjacent pump shell enclose the pump flow chamber; the axis of each pump flow chamber coincides; each pump flow chamber is provided with a piezoelectric vibrator assembly (30); the input port and the output port of the pump flow chamber are provided with a valve body (20) which limits the one-way flow of fluid; The input pump shell (10) and the intermediate pump shell (40) are provided with an air inlet flow channel (403) connected to the input port of the corresponding pump flow chamber; the intermediate pump shell (40) and the output pump shell (50) are provided with an air outlet flow channel (402) connected to the output port of the corresponding pump flow chamber; each air inlet flow channel (403) is sequentially connected to form an air inlet total flow path; each air outlet flow channel (402) is sequentially connected to form an air outlet total flow path; the air inlet total flow path is connected to the total inlet flow port (100) in the input pump shell (10); the air outlet total flow path is connected to the total outlet flow port (500) in the output pump shell (50).

2. The integrated piezoelectric micropump of a longitudinal stack structure according to claim 1, characterized in that: The edge of the opposite side of two adjacent pump shell is provided with a matching butt joint structure; the butt joint structure includes a surrounding convex structure (410) and a surrounding concave structure (411) arranged on the edge of the opposite side of two adjacent pump shell respectively; the opposite side of two adjacent pump shell is positioned and embedded through the surrounding convex structure (410) and the surrounding concave structure (411).

3. The integrated piezoelectric micropump of a longitudinal stack structure according to claim 1, characterized in that: The outer peripheral surface of the pump shell is cylindrical, and is provided with two or more convex block structures (420); the air inlet flow channel (403) and the air outlet flow channel (402) are respectively in two independent convex block structures (420).

4. The integrated piezoelectric micropump of a longitudinal stack structure according to claim 1, characterized in that: The piezoelectric vibrator assembly (30) includes a piezoelectric driving element (31), a support beam structure (32) and a frequency modulation metal substrate (33) arranged in sequence; the support beam structure (32) is provided with a plurality of flow channel series ports (301) surrounding the piezoelectric driving element (31); the pump flow chamber is communicated through the flow channel series port (301) in the area on both sides of the piezoelectric vibrator assembly (30).

5. An integrated piezoelectric micropump in a longitudinal stack structure according to claim 4, characterized in that: The support beam structure (32) is clamped between the opposite sides of the corresponding two adjacent pump shell; the outer peripheral edge of the support beam structure (32) is attached to the inner side wall of the pump shell.

6. The integrated piezoelectric micropump of a longitudinal stack structure according to claim 4, characterized in that: The frequency modulation metal substrate (33) is provided with a center thinning groove (330) on the side away from the support beam structure (32).

7. An integrated piezoelectric micropump in a longitudinal stack configuration according to claim 6, characterized in that: The diameter and depth of the center thinning groove (330) are determined by the following process: the amplitude and frequency of the piezoelectric vibrator assembly (30) under a plurality of different diameter residual thickness ratios are obtained by simulation or experiment; in the target frequency range, the diameter residual thickness ratio corresponding to the maximum amplitude is selected as the constraint condition; the diameter and depth of the center thinning groove (330) satisfying the constraint condition are obtained; the diameter residual thickness ratio is the ratio between the diameter of the center thinning groove (330) and the thickness of the frequency modulation metal substrate (33) at the position of the center thinning groove (330).

8. The integrated piezoelectric micropump of a longitudinal stack structure according to claim 4, characterized in that: The frequency modulation metal substrate (33) is also provided with an annular edge thinning groove (331) on the side away from the support beam structure (32).

9. The integrated piezoelectric micropump of a longitudinal stack structure according to claim 1, characterized in that: The valve body (20) comprises a sealing layer (24), a valve flap (23), a spacer (22) and an open layer (21) which are stacked and fixed in sequence along the flow direction; a plurality of air inlet holes (204) are arranged on the sealing layer (24); a plurality of flow holes (203) are arranged on the valve flap (23); a through groove structure is arranged in the spacer (22); a plurality of air outlet holes (201) are arranged on the open layer (21); the flow holes (203) on the valve flap (23) are arranged in a staggered manner with the air inlet holes (204) on the sealing layer (24); the flow holes (203) on the valve flap (23) are arranged in an aligned manner with the air outlet holes (201) on the open layer (21); a limiting part is arranged at the center position of the through groove structure of the spacer (22); the limiting part and the inner edge of the through groove structure are fixedly connected through a connecting beam.

10. A method of pumping gas, characterized by: The integrated piezoelectric micropump of the longitudinal stack structure of claim 1 is used; the pumping method comprises: The number n of pump flow units is set according to the target flow; the number n of pump flow units increases with the increase of the target flow; an input pump shell (10), n-1 intermediate pump shells (40), an output pump shell (50), n piezoelectric vibrator assemblies (30) and 2n valve bodies (20) are assembled into an integrated piezoelectric micropump; The piezoelectric vibrator assemblies (30) in the integrated piezoelectric micropump are input with the same excitation signal to drive the piezoelectric vibrator assemblies (30) to reciprocate; the external fluid is input into each pump flow chamber through the air inlet total flow path, is pressurized by the corresponding piezoelectric vibrator assembly (30), is combined after passing through the air outlet total flow path, and is pumped out from the total outlet (500).

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