WO2025236739A1 - Piezoelectric micro pump - Google Patents

Abstract

A piezoelectric micro pump, comprising: a pump body, which has a square cavity; a vibration isolation sheet, which is horizontally arranged in the middle position of the square cavity and divides the square cavity into an upper cavity and a lower cavity which are independent of each other, wherein two holes run through an end wall of each of the upper cavity and the lower cavity, and one hole is formed in the central position of the end wall of each cavity; one-way valves, each of which is arranged on one hole of each cavity; an actuator, which is attached to one face of the vibration isolation sheet and forms an electrical connection on the attachment face; and a deformation sheet, which is arranged on the other face of the vibration isolation sheet. The square cavity can provide a larger braking area for the actuator, thereby increasing a vibration amplitude, increasing a formed gas pressure, and providing a larger fluid pressure and flow.

Description

A piezoelectric micro pump Technical Field

This invention relates to the field of micropump technology, and more specifically to a piezoelectric micropump.

Background Technology

Piezoelectric micropumps are commonly used in portable electronic devices, such as portable blood pressure monitors and headband massagers. They are relatively small pumps used to deliver positive pressure or provide vacuum. To achieve the desired small size, high efficiency, and silent operation, these pumps must operate at very high frequencies, typically around 20 kHz or higher. To operate at high frequencies, the pump's valves must respond to high-frequency oscillating pressure, which can be rectified to generate a net fluid flow through the pump.

Existing piezoelectric micropumps suffer from limited vibration chamber area and small actuator braking area, resulting in insufficient vibration amplitude and low gas pressure. This, in turn, affects fluid pressure and flow rate. Therefore, a new piezoelectric micropump is urgently needed to solve some of the problems existing in the current technology.

Technical issues

The purpose of this invention is to provide a piezoelectric micropump to solve some problems existing in the prior art.

Technical solutions

To achieve the above objectives, the present invention adopts the following technical solution: a piezoelectric micro pump, comprising:

Pump body, wherein the pump body has a square cavity;

A vibration isolation plate is horizontally positioned in the middle of a square cavity, dividing the square cavity into two independent cavities, with two holes perforated on the end walls of the upper and lower cavities, one of which is located in the center of the end wall of the cavity.

A one-way valve, wherein the one-way valve is disposed on one of the holes in the cavity;

An actuator is attached to one side of a vibration isolator, and an electrical connection is formed on the attached surface;

A deformable sheet is disposed on the other side of the vibration isolation sheet.

Furthermore, the vibration isolation plate is made of an elastic material.

Furthermore, the vibration isolation sheet is a polyurethane film or a PET film, or the vibration isolation sheet is made of a composite material of a polyurethane film and a metal sheet, or the vibration isolation sheet is made of a composite material of a PET film and a metal sheet.

Furthermore, the planar area where the vibration isolation plate and the actuator are in contact has a pressure node, which is an irregular ring shape, and the pressure at the pressure node tends to be zero. The pressure on both sides of the pressure node is in opposite directions.

Furthermore, the one-way valve is a diaphragm valve with a pressure relief function.

Furthermore, the one-way valve includes:

A spacer having a valve area and a venting area extending through its upper and lower ends, the venting area being located beside the valve area and connected to the valve area via a connecting area;

The plate consists of two plates, which are respectively disposed on the upper and lower sides of the spacer. The two plates are vertically penetrated through the valve area and have corresponding first holes, while one plate is vertically penetrated through the venting area and has a third hole.

A valve is disposed between a spacer and a plate with a third hole. The valve and the plate with the third hole are respectively perpendicularly perforated through corresponding second holes at their positions in the valve area. The second holes are offset from the first holes.

Furthermore, the actuator is made of piezoelectric material.

Furthermore, the actuator is any one of a square actuator, a polygonal actuator, or a circular actuator.

Furthermore, electrodes are arranged on the upper and lower surfaces of the actuator, and multiple electrodes are provided on the contact surface between the actuator and the vibration isolation plate, forming an electrical connection with the multiple electrodes of the vibration isolation plate.

An annular electrode is provided on the outer side of the contact surface between the actuator and the vibration isolation plate, and the annular electrode is connected to an electrode on the other side of the actuator through a side electrical connection.

Beneficial effects

The above technical solution has the following advantages compared with the existing technology: the square cavity can provide a larger braking area for the actuator, thereby increasing the vibration amplitude, increasing the gas pressure, and resulting in greater fluid pressure and flow rate.

Attached Figure Description

To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

Figure 1 is a simplified structural diagram of the present invention;

Figure 2 is a schematic diagram of the exploded structure of the present invention;

Figure 3 is a partial structural schematic diagram of the present invention;

Figure 4 is a partial structural schematic diagram of the vibration isolation plate 2 in this invention;

Figure 5 is a pressure diagram of the present invention;

Figure 6 is a partial structural schematic diagram of the actuator 4 of the present invention when it is square;

Figure 7 is a partial structural schematic diagram of the actuator 4 of the present invention when it is a polygon;

Figure 8 is a partial structural schematic diagram of the actuator 4 of the present invention when it is circular;

Figure 9 is a schematic diagram of one structure of the single-piece valve 3 in this invention;

Figure 10 is a partial structural schematic diagram of the present invention when the valve 34 and the second plate 33 are attached;

Figure 11 is a partial structural schematic diagram of the present invention when the valve 34 and the first plate 32 are attached;

Figure 12 is a schematic diagram of another structure of the single-piece valve 3 in this invention.

Explanation of reference numerals in the attached drawings: 1. Pump body; 11. Upper pump housing; 12. Lower pump housing; 13. Upper cavity; 14. Lower cavity; 141. Fourth hole; 142. Fifth hole; 15. Air outlet; 16. Vent hole; 2. Vibration isolation plate; 21. Electrical connection input terminal; 22. Pressure node; 3. One-way valve; 31. Spacer; 311. Baffle; 312. Valve area; 313. Vent area; 314. Connecting area; 32. First plate; 33. Second plate; 34. Valve; 35. First hole; 36. Second hole; 37. Third hole; 4. Actuator; 41. Ring electrode; 411. Side electrical connection; 42. Circular electrode; 5. Deformation plate.

Embodiments of the present invention

To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

To address the problems existing in the prior art, the present invention provides a piezoelectric micropump, which will be described in detail below with reference to the accompanying drawings.

Referring to Figures 1-11, the technical solution adopted in this specific embodiment is: a piezoelectric micro pump, including a pump body 1, a vibration isolation plate 2, a one-way valve 3, an actuator 4, and a deformable plate 5. The pump body 1 includes an upper pump housing 11 and a lower pump housing 12. The upper pump housing 11 and the lower pump housing 12 are connected to form a square cavity or an approximately square cavity for containing fluid. The ratio between the side length and the height of the cavity is greater than 2.5.

A vibration isolation plate 2 is provided in the middle of the cavity, which divides the square or nearly square cavity into an upper cavity 13 and a lower cavity 14, with the two cavities being independent. Specifically, the vibration isolation plate 2 is generally square in structure, and its edges are pressed against the ends of the upper pump housing 11 and the lower pump housing 12, dividing the cavity into two independent parts. One side of the vibration isolation plate 2 extends outward from the pump body 1 to form a thin strip, the tail end of which is the electrical connection input terminal 21.

It should be specifically noted that a fourth hole 141 is respectively provided through the center of the end wall of the upper cavity 13 and the lower cavity 14, and a fifth hole 142 is also respectively provided through the end wall of the upper cavity 13 and the lower cavity 14. The fifth hole 142 is located at any position in the end wall other than the fourth hole 141. A one-way valve 3 is installed at one of the fourth hole 141 or the fifth hole 142 to allow fluid to flow through the cavity during use.

The vibration isolation plate 2 is disposed between the actuator 4 and the deformable plate 5, and an electrical connection is formed between the actuator 4 and the vibration isolation plate 2 on their mating surfaces. Specifically, electrodes are respectively provided on the upper and lower surfaces of the actuator 4, wherein at least two electrodes are provided on the mating surface of the actuator 4 and the vibration isolation plate 2, and the two or more electrodes of the actuator 4 and the vibration isolation plate 2 are electrically connected on their mating surfaces.

An annular electrode 41 is provided on the outer side of the contact surface between the actuator 4 and the vibration isolator 2. The annular electrode 41 is connected to an electrode on the other side of the actuator 4 through a side electrical connection 411. The annular electrode 41 forms electrical contact with at least one of the multiple conductive tracks of the vibration isolator 2. At this time, a circular electrode 42 is provided on the inner side of the annular electrode 41 of the actuator 4.

Preferably, the actuator 4 is made of piezoelectric material and can be a square actuator, an approximately square actuator, a polygonal actuator, or a circular actuator. After a voltage is applied to the electrodes of the actuator 4, the actuator 4 will expand or contract due to the piezoelectric effect. Since the actuator 4, the vibration isolation plate 2, and the deformable plate 5 are attached as a whole, the deformable plate 5 deforms when the actuator 4 expands or contracts. By inputting an alternating voltage to the actuator 4, the deformable plate 5 will drive the vibration isolation plate 2 to vibrate.

Preferably, the vibration isolation plate 2 is made of a material with elastic characteristics, such as polyurethane film, PET film, or a composite material of polyurethane film or PET film and metal sheet.

As shown in Figure 5, the actuator 4 and the deformable plate 5 generate waveform vibration under the action of an alternating electric field. There is a pressure node 22 in the planar area where the vibration isolation plate 2 and the actuator 4 are attached. The pressure node 22 is an irregular ring, and the pressure at this point tends to be zero. The pressure on both sides of the pressure node 22 is in opposite directions, thus forming two peak regions, one inside the pressure node 22 and the other outside the pressure node 22. Under the action of pressure, the fluid flows in one direction.

The actuator 4 shown has a driving frequency exceeding 20kHz, which is beyond the range that human hearing can perceive, and the vibration effect is close to silent.

Preferably, the one-way valve 3 is a one-way valve with pressure relief function, which has both air release and pressure relief functions. It can solve the problem that existing piezoelectric micro pumps do not have pressure relief function, which leads to the need for application equipment to be equipped with a separate pressure relief valve. It can save internal space of application equipment, reduce equipment size and reduce cost, and make it more convenient to use.

It should be specifically noted that the one-way valve 3 includes a spacer 31, a first plate 32, a second plate 33, and a valve 34. The spacer 31 has a hollow region extending longitudinally through its upper and lower ends. A baffle 311 extends horizontally within the hollow region, dividing the hollow region into a valve region 312 and a venting region 313. The valve region 312 and the venting region 313 are connected by a connecting region 314. The first plate 32 and the second plate 33 are respectively disposed on the upper and lower sides of the spacer 31. The first plate 32 and the second plate 33 have a first hole 35 perpendicularly extending through them at the position of the valve region 312. The first hole 35 on the first plate 32 and the first hole 35 on the second plate 33 are correspondingly arranged.

The valve 34 is disposed between the second plate 33 and the spacer 31. The second plate 33 and the valve 34 are respectively provided with a second hole 36 perpendicularly through them at the position of the valve area 312. The second hole 36 on the second plate 33 corresponds to the second hole 36 on the valve 34, and the second hole 36 is offset from the first hole 35.

It should be specifically noted that the second plate 33 has a third hole 37 vertically penetrating through the venting area 313. During operation, the vent 15 of the pump body 1, the second hole 36 and the third hole 37 on the second plate 33, and the vent 16 of the pump body are connected in sequence to form a venting channel.

Specifically, the connecting region 314 is located at the extension port of the baffle 311, and the area of the baffle 311 is larger than the area of the connecting region 314. Preferably, two baffles 311 are provided between the valve region 312 and the venting region 313, and the two baffles 311 are arranged symmetrically, with the connecting region 314 located between the relative extension ports of the two baffles 311.

Preferably, the valve region 312 is located at the center of the spacer 31, and its area is larger than that of the venting region 313. The area of the venting region 313 is approximately one-fifth the area of the valve region 312.

In addition, the valve area 312 can be a single, continuous area or composed of multiple interconnected areas.

It should be noted that two venting zones 313 may be provided, and the two venting zones 313 are symmetrically arranged on opposite sides of the valve area 312. In fact, the specific number of venting zones 313 is not limited to one or two, and can be adjusted according to actual design requirements.

One-way valve 3 is installed inside pump body 1. When actuator 4 is working, the vibration of actuator 4 can cause changes in airflow pressure in the cavity area. Synchronized with the input frequency, one-way valve 3 vibrates up and down at the same frequency under the change of air pressure on both sides. When valve 34 is close to second plate 33, first hole 35 of first plate 32 is connected to second hole 36 of second plate 33. At this time, the gas pressure in pump cavity is greater than that in air passage, and air pump is in exhaust state. When valve 34 is close to first plate 32, the pressure in air passage is greater than that in pump cavity, valve is in closed state, and air pump is in stop pumping state. At this time, since the up and down vibration of valve 34 is a high-frequency action at the same frequency as actuator, the action time is very short. At this time, the action area of valve 34 is only up and down in the middle area of spacer 31, and third hole 37 is closed by valve 34 and is always in closed state.

When the actuator 4 stops working, the pressure inside the pump chamber is connected to the outside, while the pressure in the outlet pipe is greater than that in the pump chamber for a long time. The valve 34 not only adheres tightly to the first plate 32 in the central area, but also in the area of the outer vent hole 16, because the pressure in the outlet pipe cannot be released, the gas will overflow to the outer area through the vent hole 15, causing the valve 34 to adhere tightly to the first plate 32, thereby opening the third hole 37, and thus opening the vent hole 16, releasing the air pressure in the outlet pipe through the vent hole 16.

When actuator 4 works again, the pressure in the pump chamber is greater than that in the outlet pipe. Under the pressure, valve 34 will close the third hole 37 and resume the high-frequency operation outlet state.

Referring to Figure 12, the valve 34 of the single-piece valve 3 can also be disposed between the first plate 32 and the spacer 31. In this case, the first plate 32 has a third hole 37 perpendicularly inserted through it at the position of the pressure relief area 313. When there is pressure on the end face of the first plate 32, the valve 34 closes the third hole 37 on the first plate 32. The function of the third hole 37 on the first plate 37 is to use air pressure to push the valve 34 onto the second plate 33.

The square or near-square cavity can provide a larger braking area for the actuator 4, thereby increasing the vibration amplitude, increasing the gas pressure, and resulting in greater fluid pressure and flow. It also has the functions of venting and depressurizing, so the application equipment does not need to install a separate depressurization valve. It can save internal space of the application equipment, reduce the size of the equipment and reduce costs. It is easy to use and has great value for promotion and application.

In the description of this invention, unless otherwise stated, "a plurality of" means two or more; the terms "upper," "lower," "left," "right," "inner," "outer," "front end," "rear end," "head," "tail," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, the terms "first," "second," "third," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

The above description is only used to illustrate the technical solution of the present invention and is not intended to limit it. Any other modifications or equivalent substitutions made by those skilled in the art to the technical solution of the present invention, as long as they do not depart from the spirit and scope of the technical solution of the present invention, should be covered within the scope of the claims of the present invention.

Claims (9)

A piezoelectric micropump, characterized in that it comprises: Pump body, wherein the pump body has a square cavity; A vibration isolation plate is horizontally positioned in the middle of a square cavity, dividing the square cavity into two independent cavities, with two holes perforated on the end walls of the upper and lower cavities, one of which is located in the center of the end wall of the cavity. A one-way valve, wherein the one-way valve is disposed on one of the holes in the cavity; An actuator is attached to one side of a vibration isolator, and an electrical connection is formed on the attached surface; A deformable sheet is disposed on the other side of the vibration isolation sheet. According to claim 1, the piezoelectric micropump is characterized in that the vibration isolation plate is made of an elastic material. According to claim 1, the piezoelectric micropump is characterized in that the vibration isolation plate is a polyurethane film or a PET film, or the vibration isolation plate is made of a composite material of a polyurethane film and a metal sheet, or the vibration isolation plate is made of a composite material of a PET film and a metal sheet. According to claim 1, the piezoelectric micropump is characterized in that the plane area where the vibration isolator and the actuator are attached has a pressure node, the pressure node is irregularly annular, the pressure at the pressure node tends to be zero, and the pressure on both sides of the pressure node is in opposite directions. According to claim 1, the piezoelectric micropump is characterized in that the one-way valve is a diaphragm valve with pressure relief function. According to any one of claims 1 or 5, the piezoelectric micropump is characterized in that the one-way valve comprises: A spacer having a valve area and a venting area extending through its upper and lower ends, the venting area being located beside the valve area and connected to the valve area via a connecting area; The plate consists of two plates, which are respectively positioned on the upper and lower sides of the spacer. The two plates have corresponding first holes perpendicularly penetrating through them at the valve area position, and a third hole perpendicularly penetrating through them at the venting area position. A valve is disposed between a spacer and any plate. The valve and one of the plates are respectively provided with corresponding second holes perpendicularly through their respective positions in the valve area. The second holes are offset from the first holes. According to claim 1, the piezoelectric micropump is characterized in that the actuator is made of piezoelectric material. According to any one of claims 1 or 7, the piezoelectric micropump is characterized in that the actuator is any one of a square actuator, a polygonal actuator, or a circular actuator. According to claim 8, the piezoelectric micropump is characterized in that electrodes are respectively arranged on the upper and lower surfaces of the actuator, and multiple electrodes are arranged on the contact surface between the actuator and the vibration isolation plate, forming an electrical connection with the multiple electrodes of the vibration isolation plate. An annular electrode is provided on the outer side of the contact surface between the actuator and the vibration isolation plate, and the annular electrode is connected to an electrode on the other side of the actuator through a side electrical connection.