Miniature piezoelectric pump

Abstract

The invention relates to the technical field of piezoelectric pumps, in particular to a miniature piezoelectric pump, which comprises a base, a water inlet, a water outlet, a pressure sensor and a pressure sensor, the valve body assembly is attached to the base, and a water inlet valve communicating with the water inlet and a water outlet valve communicating with the water outlet are arranged on the valve body assembly; the pressurizing assembly is connected with the face, away from the base, of the valve body assembly in an attached mode and comprises a hollow first partition frame, a hollow second partition frame and a pressurizing piece arranged between the first partition frame and the second partition frame in a clamped mode. The driving assembly is connected with the side, away from the valve body assembly, of the pressurizing assembly in an attached mode and comprises a substrate attached to the second partition frame and a piezoelectric plate fixed to the substrate. Wherein a pressurizing cavity is formed among the substrate, the second partition frame and the pressurizing piece, a cavity is formed by the pressurizing piece, the first partition frame and the face, away from the base, of the valve body assembly, the water inlet valve and the water outlet valve are both in one-way communication with the cavity, the pressurizing piece is provided with a hole site communicating the pressurizing cavity with the cavity, and the hole site is used for segmenting or collapsing bubbles.

Description

Technical Field

[0001] The present invention relates to the technical field of piezoelectric pumps, and in particular to a micro piezoelectric pump. Background Art

[0002] A piezoelectric pump is a micro pump that uses the piezoelectric effect to drive fluid flow. It pushes the fluid by mechanically deforming the piezoelectric material under the action of voltage. This type of pump is widely used in medical equipment, microfluidic systems, fuel supply, and portable devices, and has the advantages of simple structure, small size, and low energy consumption.

[0003] In the prior art, piezoelectric pumps mostly include a piezoelectric vibrator, a diaphragm, a pump chamber and a one-way valve. The deformation of the piezoelectric vibrator drives the reciprocating movement of the diaphragm, thereby causing periodic changes in the volume of the pump chamber, and then using the one-way valve to achieve unidirectional flow of the fluid. However, the periodic changes in the pump chamber cause the fluid in the chamber to pulsate, inevitably forming cavitation, which will further evolve into bubbles. As the valve plate opens, the bubbles flow out of the pump chamber, causing great harm to the pump body and the entire micropump drive system. Summary of the invention

[0004] In view of at least one of the above technical problems, the present invention provides a micro piezoelectric pump, which adopts structural improvement to reduce fluid pulsation in the pump chamber and reduce bubbles in the pump chamber to increase the service life of the micro pump.

[0005] According to a first aspect of the present invention, there is provided a micro piezoelectric pump, comprising: A base, wherein the base has a water inlet and a water outlet; A valve body assembly is arranged in close contact with the base, and the valve body assembly has a water inlet valve connected to the water inlet and a water outlet valve connected to the water outlet; A booster assembly is closely connected to a side of the valve body assembly facing away from the base, and comprises a first bulkhead and a second bulkhead arranged hollowly, and a booster sheet sandwiched between the first bulkhead and the second bulkhead; A driving assembly is attached to a side of the boosting assembly facing away from the valve body assembly, and includes a substrate attached to the second bulkhead and a piezoelectric sheet fixed on the substrate; A boosting cavity is formed between the base plate, the second bulkhead and the boosting plate, a mold cavity is formed between the boosting plate, the first bulkhead and a side of the valve body assembly facing away from the base, the water inlet valve and the water outlet valve are both unidirectionally connected to the mold cavity, and a hole connecting the boosting cavity and the mold cavity is provided on the boosting plate, and the hole is used to split or collapse bubbles.

[0006] In some embodiments of the present invention, a plurality of the boosting assemblies are stacked between the valve body assembly and the drive assembly, and the hole positions and diameters on the plurality of the boosting sheets are different.

[0007] In some embodiments of the present invention, the holes on the plurality of pressure boosting sheets are arranged in a staggered manner.

[0008] In some embodiments of the present invention, the valve body assembly includes a lower support plate, a valve sheet, and an upper support plate; The valve sheet is provided with a valve body which is deformable in the thickness direction, and the valve sheet is sandwiched between the upper support plate and the lower support plate; The upper support plate and the lower support plate are both provided with a water inlet hole and a water outlet hole which are arranged corresponding to the valve body.

[0009] In some embodiments of the present invention, the water inlet hole on the lower support plate and the water outlet hole on the upper support plate are respectively located on two sides of the valve body.

[0010] In some embodiments of the present invention, the diameter of the valve body is larger than the diameter of the water inlet hole, the diameter of the water outlet hole is larger than the diameter of the valve body, and the valve body is movably arranged toward the water outlet hole.

[0011] In some embodiments of the present invention, the valve body is also connected to a plurality of cantilevers in the circumferential direction, one end of the cantilever is fixed to the valve plate, and the other end is fixed to the edge of the valve body, and the cantilever is arranged in a circuitous manner on the plane where the valve plate is located.

[0012] In some embodiments of the present invention, the surface of the water inlet hole facing the valve plate further has an annular groove.

[0013] In some embodiments of the present invention, the pressure boosting sheet is made of a flexible material and can be deformed in the thickness direction.

[0014] In some embodiments of the present invention, the water outlet cross-sectional area of ​​the water outlet hole is smaller than the area of ​​the hole position.

[0015] The beneficial effects of the present invention are as follows: by adding a boosting component in the pump cavity and setting the holes on the boosting plate in the boosting component, when a relatively large volume of cavitation evolves into bubbles in the cavity or boosting cavity of the micropump, the bubbles continuously shuttle back and forth in the holes of the boosting plate as the fluid flows, and bubbles with a diameter larger than the hole are cut into a number of small bubbles smaller than the hole diameter or directly collapse. By setting the above structure, compared with the prior art, the formation of cavitation and the outflow of bubbles are reduced, thereby ensuring that the pump body and the entire pump drive system will not be excessively worn due to the evolution of cavitation and bubbles, thereby extending the service life of the liquid micropump. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0017] Figure 1 Schematic diagram of the explosion decomposition structure of the micro piezoelectric pump in an embodiment of the present invention; Figure 2 Schematic diagram of the bottom view of the micro piezoelectric pump in an embodiment of the present invention; Figure 3 In the embodiment of the present invention Figure 2 AA section structural diagram; Figure 4 It is a schematic diagram of the structure of multiple boosting sheets in an embodiment of the present invention; Figure 5 A schematic diagram of a staggered hole structure of a plurality of boosting sheets in an embodiment of the present invention; Figure 6 It is a schematic diagram of the exploded structure of the valve body assembly in an embodiment of the present invention; Figure 7 It is a schematic diagram of an exploded structure of a valve body assembly from another perspective in an embodiment of the present invention; Figure 8 In the embodiment of the present invention Figure 6 A local enlarged view of point B in FIG. Fig. 9 In the embodiment of the present invention Figure 6 A local enlarged view of point C in FIG. Fig.10 In the embodiment of the present invention Figure 3 A local enlarged view of point D in FIG. Fig.11 It is a partial enlarged structural schematic diagram of the boosting plate and the valve plate when pumping out in an embodiment of the present invention; Fig.12 Schematic diagram of flow velocity simulation at the water inlet and outlet of the piezoelectric pump in an embodiment of the present invention. DETAILED DESCRIPTION

[0018] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0019] It should be noted that when an element is referred to as being "fixed to" another element, it may be directly on the other element or there may be a central element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. The terms "vertical", "horizontal", "left", "right" and similar expressions used herein are for illustrative purposes only and do not represent the only implementation method.

[0020] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more related listed items.

[0021] like Figures 1 to 12 The micro piezoelectric pump shown in the figure includes a base 1, a valve body assembly 2, a booster assembly 3 and a drive assembly 4, as shown in FIG. Figures 1 to 3 As shown in the figure: the base 1 has a water inlet 11 and a water outlet 12; in the embodiment of the present invention, the water inlet 11 and the water outlet 12 appear in pairs, and the base 1 can be made of metal or composite materials, such as stainless steel, aluminum alloy, polyimide, polyformaldehyde or ceramic materials, etc. When the water inlet 11 or the water outlet 12 is processed, CNC processing or injection molding technology can be used. The valve body assembly 2 is fitted with the base 1, and the valve body assembly 2 has an inlet valve 21 connected to the water inlet 11 and an outlet valve 22 connected to the water outlet 12; in an embodiment of the present invention, the inlet valve 21 and the outlet valve 22 are both unidirectionally connected, and the valve body assembly 2 can be processed by compression molding or laser cutting or thin film processing; the boosting assembly 3 is fitted with the side of the valve body assembly 2 facing away from the base 1, including a hollow first bulkhead 31 and a second bulkhead 32 and a boosting sheet 33 sandwiched between the first bulkhead 31 and the second bulkhead 32; the driving assembly 4 is fitted with the side of the boosting assembly 3 facing away from the valve body assembly 2, including a substrate 41 fitted on the second bulkhead 32 and a piezoelectric sheet 42 fixed on the substrate 41; the piezoelectric sheet 42 will reciprocate in the thickness direction after being excited, thereby driving the substrate 41 to deform in the thickness direction, thereby changing the pressure in the boosting chamber 32a.

[0022] In an embodiment of the present invention, a boosting cavity 32a is formed between the substrate 41, the second bulkhead 32 and the boosting sheet 33, the boosting sheet 33, the first bulkhead 31 and the side of the valve body assembly 2 facing away from the base 1 form a cavity 31a, the water inlet valve 21 and the water outlet valve 22 are both in one-way communication with the cavity 31a, and the boosting sheet 33 has a hole 33a connecting the boosting cavity 32a and the cavity 31a, and the hole 33a is used to divide or collapse the bubbles. Of course, it should be pointed out here that the number of the hole 33a can be multiple. In an embodiment of the present invention, the size of the set hole 33a is generally in the range of tens to hundreds of microns, and is selected according to the viscosity of different liquids. The higher the viscosity, the larger the aperture is set.

[0023] In the above embodiment, by adding a boosting component 3 in the pump cavity and setting the hole 33a on the boosting plate 33 in the boosting component 3, when a larger volume of cavitation evolves into bubbles in the cavity 31a or the boosting cavity 32a of the micropump, the bubbles continuously shuttle back and forth in the hole 33a of the boosting plate 33 with the flow of the fluid, and the bubbles with a diameter larger than the hole are cut into a number of small bubbles smaller than the diameter of the hole or directly collapse. By setting the above structure, compared with the prior art, the formation of cavitation and the outflow of bubbles are reduced, thereby ensuring that the pump body and the entire pump drive system will not be worn too quickly due to the evolution of cavitation and bubbles, thereby extending the service life of the liquid micropump.

[0024] On the basis of the above embodiments, it should be pointed out in the embodiments of the present invention that the number of the boosting components 3 is not limited to Figure 3 A single form in which there can be multiple, such as Figure 4 As shown in , in some embodiments of the present invention, the boosting assembly 3 is stacked with multiple holes 33a between the valve body assembly 2 and the drive assembly 4, and the apertures of the holes 33a on the multiple boosting sheets 33 are different. By changing the apertures between the multiple layers of boosting sheets 33, the bubbles can be divided multiple times, thereby achieving the effect of reducing the bubbles. In addition, the design of multiple holes 33a increases the flow rate, helps avoid the accumulation of solid particles or impurities, and reduces the risk of clogging of the pump in a complex environment, thereby improving the reliability of the pump and extending the service life of the liquid micropump and the entire pump drive system.

[0025] In addition, in other embodiments of the present invention, in order to further mention the effect of breaking or collapsing the bubbles, as Figure 5 As shown in the figure, the holes 33a on the multiple boosting sheets 33 are arranged in a staggered manner. The staggered arrangement of the holes 33a on the boosting sheets 33 avoids the accumulation of bubbles when passing through the multiple boosting sheets 33 at the same position, ensures the smooth flow of the fluid when passing through the pump chamber, and enhances the segmentation and collapse effect of the bubbles.

[0026] In the embodiment of the present invention, the specific structure of the valve body assembly 2 is as follows: Figure 6 and Figure 7 As shown in , the valve body assembly 2 includes a lower support plate 23, a valve plate 24 and an upper support plate 25; the valve plate 24 has a valve body 24a that can be deformed in the thickness direction, and the valve plate 24 is sandwiched between the upper support plate 25 and the lower support plate 23; the upper support plate 25 and the lower support plate 23 both have a water inlet hole 23a and a water outlet hole 23b that are arranged corresponding to the valve body 24a. Through the arrangement of this structure, the upper support plate 25 and the lower support plate 23 fix the valve plate 24, and then in the embodiment of the present invention, the correspondence between the water inlet hole 23a and the water outlet hole 23b means that the water inlet hole 23a on the lower support plate 23 and the water outlet hole 23b on the upper support plate 25 are respectively located on both sides of the valve body 24a. That is, the upper side of the valve body 24a is the water outlet hole 23b and the lower side is the water inlet hole 23a, or they are arranged in reverse.

[0027] In an embodiment of the present invention, the valve body 24a, the water inlet hole 23a and the water outlet hole 23b are set to a circular structure, the diameter of the valve body 24a is larger than the diameter of the water inlet hole 23a, the diameter of the water outlet hole 23b is larger than the diameter of the valve body 24a, and the valve body 24a is movable toward the water outlet hole 23b. In this way, in the thickness direction, when the valve body 24a moves toward the water inlet hole 23a, it can be attached to the water inlet hole 23a to achieve closure. For example, when the pressure in the pump chamber increases, the water outlet hole 23b applies positive pressure to the valve body 24a toward one side of the pump chamber, so that the valve body 24a is attached to the water inlet hole 23a, and the liquid cannot pass through at this time; on the contrary, the valve body 24a can be moved toward the water outlet hole 23b to achieve the opening of the valve body 24a.

[0028] In some embodiments of the present invention, regarding the specific connection structure of the valve body 24a, such as Figure 8 As shown in the figure, the valve body 24a is also connected to a plurality of cantilevers 24b in the circumferential direction, one end of the cantilever 24b is fixed to the valve plate 24, and the other end is fixed to the edge of the valve body 24a, and the cantilever 24b is arranged in a circuitous manner on the plane where the valve plate 24 is located. The arrangement of the cantilever 24b realizes the suspended support of the valve body 24a, and the circuitous arrangement of the cantilever 24b improves the elasticity of the cantilever 24b in the thickness direction, and the uniform arrangement in the circumferential direction improves the uniformity of the force on the valve body 24a, thereby extending the service life of the valve body 24a.

[0029] In some embodiments of the present invention, Fig. 9 and Fig.10 As shown in FIG. 1 , the surface of the water inlet hole 23a facing the valve plate 24 also has an annular groove. The annular groove is opened on the circumference of the water inlet hole 23a, as shown in FIG. Fig.10As shown, through the setting of the annular groove, when the valve body 24a is opened, the liquid can first enter the annular groove, thereby providing more space for the flow of the liquid, and the liquid entering the annular groove can provide power for the opening of the valve body 24a, further ensuring the stability of the liquid flow when the valve body 24a is opened.

[0030] Please refer to Fig.11 and Fig.12 , in the embodiment of the present invention, by means of the setting of the pressure increasing cavity 32a and the holes 33a on the pressure increasing sheet 33, the embodiment of the present invention also aims to increase the back pressure of the pump body. In the prior art, the overall volume of the micropump is increased by increasing the volume of the pump cavity to increase the overall flow rate of the micropump. However, in the way of increasing the pump cavity volume, although the flow rate has increased, the output pressure has significantly decreased, and if the flow path resistance of the liquid micropump drive system is large, simply increasing the volume may not be able to effectively overcome it, and even lead to a still low flow rate or a decrease in the output flow rate. In order to overcome the above problems, the present invention utilizes the volume in the enlarged pump cavity and reasonably optimizes the internal structure design, not only effectively increasing the overall output flow rate of the micropump, but also synchronously increasing the back pressure of the micropump. Specifically, please refer to Fig.11 , in the embodiment of the present invention, the pressure increasing sheet 33 is made of a flexible material and can deform in the thickness direction. That is, as Fig.11 shown, when the piezoelectric sheet 42 drives the substrate 41 to bend downward, the fluid will drive the pressure increasing sheet 33 to bend downward, and when the fluid in the cavity 31a flows through the holes 33a, its flow rate increases and the kinetic energy increases; in the embodiment of the present invention, the design of the pressure increasing sheet 33 with multiple holes can concentrate the fluid after flowing out of the holes 33a at the positions corresponding to the water inlet hole 23a and the water outlet hole 23b. This kind of concentration effect can more efficiently convert the kinetic energy of the fluid into pressure and discharge it, so as to overcome the problem that the back pressure of the micropump decreases when the pump cavity increases.

[0031] Specifically, as Fig.11 shown, the cross-sectional area of the water outlet of the water outlet hole 23b is smaller than the area of the holes 33a. Because, specifically according to the continuity equation, it is known that: A1*V1 = A2*V2. Since A1 > A2, so V1 < V2; and according to Bernoulli's principle, it is known that: where the flow rate is small, the pressure is high. Therefore, the pressure at A1 is greater than the pressure in the cavity 31a and at the outlet. As Fig.12As shown in the figure, it is a flow velocity simulation diagram at the water inlet 11 and the water outlet 12 in the embodiment of the present invention. It can be seen from the figure that the flow velocity at the outlet is significantly increased through the above-mentioned structural improvement in the embodiment of the present invention. Of course, it should be pointed out here that in the embodiment of the present invention, the output flow rate and back pressure can be improved by further increasing the driving frequency of the piezoelectric sheet 42. When manufacturing the various components of the above-mentioned micro piezoelectric pump of the present invention, a solid phase diffusion welding combination method can be adopted to improve the manufacturing efficiency and reduce the cost.

[0032] Those skilled in the art should understand that the present invention is not limited to the above embodiments, and the above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, and these changes and improvements fall within the scope of the present invention to be protected. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. A micro piezoelectric pump, characterized in that: include: A base, wherein the base has a water inlet and a water outlet; A valve body assembly is arranged in close contact with the base, and the valve body assembly has a water inlet valve connected to the water inlet and a water outlet valve connected to the water outlet; A booster assembly is closely connected to a side of the valve body assembly facing away from the base, and comprises a first bulkhead and a second bulkhead arranged hollowly, and a booster sheet sandwiched between the first bulkhead and the second bulkhead; A driving assembly is attached to a side of the boosting assembly facing away from the valve body assembly, and includes a substrate attached to the second bulkhead and a piezoelectric sheet fixed on the substrate; A boosting cavity is formed between the base plate, the second bulkhead and the boosting plate, a mold cavity is formed between the boosting plate, the first bulkhead and a side of the valve body assembly facing away from the base, the water inlet valve and the water outlet valve are both unidirectionally connected to the mold cavity, and a hole connecting the boosting cavity and the mold cavity is provided on the boosting plate, and the hole is used to split or collapse bubbles.

2. The micro piezoelectric pump according to claim 1, characterized in that: The boosting components are stacked in multiple layers between the valve body component and the driving component, and the hole positions and diameters on the multiple boosting plates are different.

3. The micro piezoelectric pump according to claim 2, characterized in that: The holes on the plurality of pressure boosting sheets are arranged in a staggered manner.

4. The micro piezoelectric pump according to claim 1, characterized in that: The valve body assembly comprises a lower support plate, a valve sheet and an upper support plate; The valve sheet is provided with a valve body which is deformable in the thickness direction, and the valve sheet is sandwiched between the upper support plate and the lower support plate; The upper support plate and the lower support plate are both provided with a water inlet hole and a water outlet hole which are arranged corresponding to the valve body.

5. The micro piezoelectric pump according to claim 4, characterized in that: The water inlet hole on the lower support plate and the water outlet hole on the upper support plate are respectively located on two sides of the valve body.

6. The micro piezoelectric pump according to claim 5, characterized in that: The diameter of the valve body is larger than the diameter of the water inlet hole, the diameter of the water outlet hole is larger than the diameter of the valve body, and the valve body is movably arranged toward the water outlet hole.

7. The micro piezoelectric pump according to claim 6, characterized in that: The valve body is also connected to a plurality of cantilevers in the circumferential direction, one end of the cantilever is fixed to the valve plate, and the other end is fixed to the edge of the valve body, and the cantilever is arranged in a circuitous manner on the plane where the valve plate is located.

8. The micro piezoelectric pump according to claim 7, characterized in that: The surface of the water inlet hole facing the valve plate is also provided with an annular groove.

9. The micro piezoelectric pump according to claim 4, characterized in that: The pressure boosting sheet is made of a flexible material and can be deformed in the thickness direction.

10. The micro piezoelectric pump according to claim 9, characterized in that: The water outlet cross-sectional area of ​​the water outlet hole is smaller than the area of ​​the hole position.

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