Piezoelectric bicrystal cantilever beam valveless ultrasonic air pump array working in second-order mode

Abstract

The invention discloses a piezoelectric bicrystal cantilever beam valveless ultrasonic air pump array working in a second-order mode, and belongs to the technical field of valveless piezoelectric air pumps, the piezoelectric bicrystal cantilever beam valveless ultrasonic air pump array adopts a lamellar structure, and comprises a cantilever beam combination plate positioned in the middle, and fixed plates, a Tesla flow channel inner layer plate and a Tesla flow channel outer layer plate which are symmetrically and fixedly connected to the upper side and the lower side of the cantilever beam combination plate in sequence; a plurality of pairs of piezoelectric bicrystal cantilever beams are symmetrically arranged on the left side and the right side of the cantilever beam combination plate, and I-shaped inner partition plates are arranged at the adjacent positions of the piezoelectric bicrystal cantilever beams. The front end and the rear end of the pump body are fixedly connected in a sealed mode through outer partition plates to form multiple pairs of pump cavities which are bilaterally symmetrical and do not interfere with each other. Adjacent structures of the Tesla runner outer layer plates and the Tesla runner inner layer plates on the same side form a plurality of pairs of Tesla runners; and the Tesla flow channel is outwards communicated with the flow inlet and is inwards communicated with the upper side or the lower side of the pump cavity through the pump cavity flow inlet hole. In conclusion, rapid suction and discharge of fluid can be achieved, and the heat dissipation device can be applied to the field of heat dissipation of precision machinery.

Description

Technical Field

[0001] This invention belongs to the field of valveless piezoelectric pump technology, specifically relating to a valveless ultrasonic air pump array with a piezoelectric bicrystalline cantilever beam operating in the second-order mode. Background Technology

[0002] Piezoelectric pumps have advantages such as small size, light weight, high precision, simple structure, low energy consumption, and low noise. In recent years, they have become one of the important research directions for researchers in the pump field at home and abroad, and have been widely used in aerospace, electronic device heat dissipation and other fields.

[0003] Piezoelectric pumps work by utilizing the inverse piezoelectric effect unique to piezoelectric materials. When an alternating excitation is applied to the piezoelectric ceramic on the piezoelectric wafer, deformation occurs inside the piezoelectric ceramic, which manifests as macroscopic vibration. This forces a change in the volume of the pump chamber, which in turn causes a change in the pressure inside the chamber, thereby achieving fluid transfer.

[0004] Traditional piezoelectric pumps experience performance degradation over long-term operation, leading to insufficient flow rate and heat dissipation. Ordinary valveless piezoelectric pumps, lacking valves to prevent fluid backflow, are prone to backflow during operation, which not only reduces efficiency but also causes fluid buildup within the pump chamber. Furthermore, some intelligent small-scale machinery applications have maximum noise level limitations, which conventional valveless piezoelectric pumps cannot adequately meet, necessitating further in-depth research.

[0005] In summary, there is an urgent need in this field for a new type of valveless piezoelectric pump structure to solve problems such as low efficiency of unidirectional fluid flow, limited pumping flow, insufficient lifespan of piezoelectric pumps, and excessive noise. Summary of the Invention

[0006] The purpose of this invention is to solve the problems existing in the field of valveless piezoelectric pump technology, and to provide a valveless ultrasonic air pump array of piezoelectric bicrystalline cantilever beam operating in the second-order mode to meet current application needs.

[0007] A valveless ultrasonic air pump with a piezoelectric dual crystal cantilever beam 5 operating in the second-order mode includes: a Tesla flow channel outer plate 1, a Tesla flow channel inner plate 2, a cantilever beam composite plate 4, and an outer partition plate 7.

[0008] The outer layer plate 1 of the Tesla flow channel has an inlet 9 in the middle of the Tesla flow channel, and the inner layer plate 2 of the Tesla flow channel has pump chamber inlet holes 10 on both sides.

[0009] The cantilever beam composite plate 4 consists of a central straight beam and cantilever beams symmetrically arranged on its left and right sides, and a fixed plate 3; the upper and lower sides of the central straight beam are fixedly connected to the fixed plate 3;

[0010] The cantilever beam has piezoelectric wafers attached to both sides to form a piezoelectric bicrystalline cantilever beam 5;

[0011] The upper and lower fixed plates 3 are sequentially sealed and fixed to the inner layer plate 2 of the Tesla flow channel and the outer layer plate 1 of the Tesla flow channel, and then the left and right ends are closed by the outer partition plates 7 to form two symmetrical double-pump cavities 15. The outflow port 16 is arranged on the pump cavity 15 opposite to the middle straight beam.

[0012] The outer layer plate 1 of the Tesla flow channel and the inner layer plate 2 of the Tesla flow channel are sealed and fixed to form two symmetrical Tesla flow channels.

[0013] Fluids pass through the inflow port 9, the Tesla flow channel, the pump cavity inflow hole 10, the pump cavity 15, and are discharged from the outflow port 16.

[0014] The valveless ultrasonic air pump array of the piezoelectric bimorph cantilever beam 5 working in the second-order mode comprises two or more parallel valveless ultrasonic air pumps of the piezoelectric bimorph cantilever beam 5 working in the second-order mode. The ultrasonic air pumps are separated by the inner partition plate 6, and the left and right sides are closed by the outer partition plate 7.

[0015] The piezoelectric bimorph cantilever beam 5 works in the second-order mode, and the vibration frequency is in the ultrasonic range.

[0016] The pump cavity inflow hole 10 is arranged at the center of the local deformation gradient secondary small area 17 of the piezoelectric bimorph cantilever beam 5.

[0017] The Tesla flow channel 8 is perpendicular to the axes of the inflow port 9 and the pump cavity inflow hole 10.

[0018] The left and right symmetrical Tesla flow channels 8 are in “X” distribution, the inflow port 9 is connected to four Tesla flow channel units, the end of each Tesla flow channel unit is connected to the corresponding pump cavity 15 through the pump cavity inflow hole 10, that is, each pump cavity 15 corresponds to two Tesla flow channel units for fluid transportation.

[0019] Another object of the present application is to provide a method for using the valveless ultrasonic air pump array of the piezoelectric bimorph cantilever beam working in the second-order mode. The valveless ultrasonic air pump array of the piezoelectric bimorph cantilever beam working in the second-order mode is used.

[0020] Step 1: According to the requirements, the number of pump cavities is selected, and the device is installed on the surface of the component (including the gap) that needs to be cooled.

[0021] Step 2: Apply an alternating current signal to the upper and lower piezoelectric wafers of the plurality of piezoelectric bimorph cantilever beams 5 to make them ultrasonically vibrate in the second-order mode.

[0022] Step 3: According to the actual working condition, the piezoelectric bimorph cantilever beam 5 is activated dynamically through the controller to adapt to the dynamic load demand.

[0023] Step 4: The piezoelectric bicrystalline cantilever beam 5 vibrates up and down to achieve rapid up and down suction and side discharge of fluid, thereby achieving heat dissipation of the component.

[0024] This invention provides a valveless ultrasonic air pump array with piezoelectric bicrystalline cantilever beams operating in the second-order mode, belonging to the field of valveless piezoelectric pump technology. It adopts a layered structure, including: a cantilever beam assembly plate located in the middle, and fixed plates, an inner Tesla flow channel plate, and an outer Tesla flow channel plate symmetrically fixed to its upper and lower sides; multiple pairs of piezoelectric bicrystalline cantilever beams 5 symmetrically arranged on the left and right sides of the cantilever beam assembly plate, with adjacent "I-shaped" inner partitions at the adjacent locations of the piezoelectric bicrystalline cantilever beams 5; the front and rear ends of the pump body are sealed and fixedly connected by outer partitions, forming multiple pairs of pump chambers that are symmetrical and do not interfere with each other; adjacent structures of the outer and inner Tesla flow channel plates on the same side form multiple pairs of Tesla flow channels; the Tesla flow channels communicate outward with the inlet and inward with the upper or lower side of the pump chamber through the pump chamber inlet hole. In summary, this invention can achieve rapid fluid intake and exhaust, and can be applied in the field of heat dissipation for precision machinery.

[0025] In summary, the beneficial effects of the technical solution adopted in this invention compared with the prior art are as follows:

[0026] 1. In this invention, the cavity is modularized (multiple pump cavities). The vibration of the piezoelectric bicrystalline cantilever beam in the second mode is used to change the pump cavity volume, so that the pump cavity volume changes periodically. The pressure difference and Tesla flow channel structure are used to achieve the effect of unidirectional fluid flow. At the same time, the pump cavity unit can be adjusted by voltage to meet different application scenarios. It is easy to array and modularize, and is suitable for integration into microsystems. The upper and lower double piezoelectric crystals are driven by opposite phase voltages, which can generate a synergistic bending effect and increase the local strain of the piezoelectric cantilever beam.

[0027] 2. In this invention, the piezoelectric bicrystalline cantilever beam vibrates up and down in the second-order mode, and its strain distribution presents a peak and a trough shape; the pump cavity inlet hole corresponds to the center (peak or trough) of its local deformation gradient second largest region; therefore, the pump cavity volume change caused by the piezoelectric bicrystalline cantilever beam 5 can be maximized, thereby maximizing the pumping fluid efficiency.

[0028] 3. The piezoelectric bicrystalline cantilever beam 5 of the present invention vibrates in the second mode, and its second mode vibration frequency is in the ultrasonic range, which meets the requirements for low noise use.

[0029] 4. The pump chamber in this invention is distributed in a symmetrical array, and the number of array units can be increased as needed to meet different application scenarios.

[0030] 5. In use, the multiple piezoelectric bicrystalline cantilever beams 5 of this invention can be selectively activated to adapt to dynamic load requirements (such as precise medical mist discharge), making the performance more efficient and the jet more concentrated.

[0031] 6. The plurality of pump cavities in the present application can be set to alternate operation, prolonging the overall service life of the piezoelectric pump array and reducing operating costs.

[0032] 7. The piezoelectric pump cavity inlet in the present application is provided with a Tesla flow channel structure, which can smoothly pass through the fluid in the forward flow, and form complex vortex and pressure distribution when passing in the reverse direction, so as to achieve the effect of forward conduction and reverse cut-off, and improve the overall inflow efficiency. BRIEF DESCRIPTION OF DRAWINGS

[0033] Figure 1 It is an exploded schematic diagram of the piezoelectric bimorph cantilever beam 5 valveless ultrasonic gas pump array working in the second order mode of the present application;

[0034] Figure 2 It is a schematic diagram of the overall structure of the piezoelectric bimorph cantilever beam 5 valveless ultrasonic gas pump array working in the second order mode of the present application;

[0035] Figure 3 It is a schematic diagram of the outer side structure of the outer layer plate of the Tesla flow channel of the piezoelectric bimorph cantilever beam 5 valveless ultrasonic gas pump array working in the second order mode of the present application;

[0036] Figure 4 It is a schematic diagram of the inner side structure of the inner layer plate of the Tesla flow channel of the piezoelectric bimorph cantilever beam 5 valveless ultrasonic gas pump array working in the second order mode of the present application;

[0037] Figure 5 It is a schematic diagram of the outer side structure of the inner layer plate of the Tesla flow channel of the piezoelectric bimorph cantilever beam 5 valveless ultrasonic gas pump array working in the second order mode of the present application;

[0038] Figure 6 It is a schematic diagram of the inner side structure of the inner layer plate of the Tesla flow channel of the piezoelectric bimorph cantilever beam 5 valveless ultrasonic gas pump array working in the second order mode of the present application;

[0039] Figure 7 It is a schematic diagram of the inner partition plate structure of the piezoelectric bimorph cantilever beam 5 valveless ultrasonic gas pump array working in the second order mode of the present application;

[0040] Figure 8 It is a schematic diagram of the outer partition plate structure of the piezoelectric bimorph cantilever beam 5 valveless ultrasonic gas pump array working in the second order mode of the present application;

[0041] Figure 9 It is a schematic diagram of the piezoelectric wafer adhered to the cantilever beam assembly plate structure of the piezoelectric bimorph cantilever beam 5 valveless ultrasonic gas pump array working in the second order mode of the present application;

[0042] Figure 10 It is a schematic diagram of the principle structure of the piezoelectric bimorph cantilever beam 5 valveless ultrasonic gas pump array working in the second order mode of the present application;

[0043] Figure 11 Fig. A is a schematic diagram of the working principle of the piezoelectric bimorph cantilever 5 valveless ultrasonic air pump array of the present application working in the second order mode;

[0044] Figure 12 Fig. B is a schematic diagram of the working principle of the piezoelectric bimorph cantilever 5 valveless ultrasonic air pump array of the present application working in the second order mode;

[0045] Figure 13 Fig. A is a schematic diagram of the working principle of the piezoelectric bimorph cantilever 5 valveless ultrasonic air pump array of the present application working in the second order mode;

[0046] Figure 14 Fig. B is a schematic diagram of the working principle of the piezoelectric bimorph cantilever 5 valveless ultrasonic air pump array of the present application working in the second order mode;

[0047] In the drawings:

[0048] 1. Tesla flow channel outer layer plate; 2. Tesla flow channel inner layer plate; 3. Fixed plate; 4. Cantilever beam combination plate; 5. Piezoelectric bimorph cantilever beam; 6. Inner partition plate; 7. Outer partition plate; 8. Tesla flow channel; 9. Inflow port; 10. Pump cavity inflow hole; 11. Positioning groove; 12. Mortise and tenon protrusion; 13. Mortise and tenon groove; 14. Positioning pin; 15. Pump cavity; 16. Outflow port; 17. Piezoelectric bimorph cantilever beam local deformation gradient sub-large area; 18. Piezoelectric bimorph cantilever beam local deformation gradient maximum area. DETAILED DESCRIPTION

[0049] The present application will be further described in detail below with reference to the accompanying drawings and specific examples. Figures 1-14

[0050] Example 1:

[0051] The pump body of the piezoelectric bimorph cantilever valveless ultrasonic air pump array working in the second order mode is rectangular, and adopts a sheet layer structure symmetrically connected up and down, comprising:

[0052] A cantilever beam combination plate 4 located in the middle, and a fixed plate 3, a Tesla flow channel inner layer plate 2, and a Tesla flow channel outer layer plate 1 symmetrically and fixedly connected in sequence on the upper and lower sides thereof;

[0053] The cantilever beam combination plate 4 is composed of a middle straight beam and 5 pairs of cantilever beams symmetrically arranged on the left and right sides thereof;

[0054] The middle straight beam is fixedly connected with the fixed plate 3, and both are rectangular and have consistent width and length;

[0055] The cantilever beams have piezoelectric crystals bonded on the upper and lower sides thereof, forming piezoelectric bimorph cantilever beams 5; ​

[0056] The piezoelectric bimorph cantilever beam 5 is provided with an "H-shaped" inner partition plate 6 adjacent to the piezoelectric bimorph cantilever beam 5; the upper and lower ends of the inner partition plate 6 are provided with positioning pins 14, and the positioning pins 14 are sealingly and fixedly connected with positioning grooves 11 arranged on the inner side of the Tesla flow channel inner layer plate 2.

[0057] The front and rear ends of the pump body are sealingly and fixedly connected with the Tesla flow channel inner layer plate 2 and the Tesla flow channel outer layer plate 1 through outer partition plates 7 and tenons and mortises 12 and mortise grooves 13, thereby forming ten pairs of left-right symmetrical pump cavities 15 (2 layers in total, 5 pairs in each layer, and 20 pump cavities in total).

[0058] The adjacent structures of the Tesla flow channel outer layer plate 1 and the Tesla flow channel inner layer plate 2 on the same side form five pairs of left-right symmetrical Tesla flow channels 8.

[0059] The outer side of the upper and lower Tesla flow channel outer layer plates 1 is provided with five inflow ports 9 arranged in front and back, and the inflow ports 9 are respectively connected with the left-right symmetrical Tesla flow channels 8 inward and are connected with the external fluid outward.

[0060] Each pair of left-right symmetrical Tesla flow channels 8 is connected with the upper side or the lower side of the pump cavity 15 through the pump cavity inflow holes 10 arranged on the left and right sides of the Tesla flow channel inner layer plate 2.

[0061] The left side or the right side of the pump cavity 15 is provided with an outflow port 16 connected with the external fluid, that is, the outflow port 16 is arranged on the two sides of the pump body and is connected with the pump cavity 15.

[0062] The piezoelectric bimorph cantilever beam 5 vibrates at the second order mode during operation, and the second order mode vibration frequency is in the ultrasonic range.

[0063] The pump cavity inflow hole 10 is arranged at the center of the local deformation gradient secondary small area 17 of the piezoelectric bimorph cantilever beam 5 during operation, that is, the position corresponding to the wave trough position of the strain distribution of the piezoelectric bimorph cantilever beam 5 at the second order mode.

[0064] The Tesla flow channel 8 is perpendicular to the axis of the inflow port 9 and the pump cavity inflow hole 10 connected therewith.

[0065] The left-right symmetrical Tesla flow channels 8 are arranged in an "X-shaped" distribution, the inflow port 9 is connected with four Tesla flow channel units inward, and the end of each Tesla flow channel unit is connected with the corresponding pump cavity 15 through the pump cavity inflow hole 10, that is, each pump cavity 15 is connected with two pump cavity inflow holes 10 (two Tesla flow channel units) for fluid transportation.

[0066] In actual use, the depth of the positioning groove 11 and the thickness of the fixed plate 3 can be adjusted to further adjust the height of the pump cavity 15 according to the actual working condition.

[0067] In summary, the piezoelectric bimorph cantilever beam valveless ultrasonic air pump array of the present application works in the second order mode, the volume of the pump cavity is changed by the vibration of the piezoelectric bimorph cantilever beam 5 in the second order mode, the volume of the pump cavity is periodically changed, the pressure difference and the check valve are used to achieve the effect of one-way flow of fluid; the position of the pump cavity inlet hole corresponds to the center area with the second smallest local deformation gradient, the volume change of the pump cavity caused by the piezoelectric bimorph cantilever beam 5 can be maximized to maximize the pumping fluid efficiency; the multiple pump cavities are separated from each other to avoid jet interference and keep the structure compact.

[0068] The piezoelectric bimorph cantilever beam 5 valveless ultrasonic air pump array of the present application works in the second order mode, and its working principle is as follows:

[0069] The piezoelectric bimorph cantilever beam valveless ultrasonic air pump array of the present application can realize the simultaneous work of multiple arrays working in the second order mode of the piezoelectric bimorph cantilever beam, forming multiple jet beams, and the working principle of multiple piezoelectric bimorph cantilever beam 5 valveless ultrasonic air pumps working in the second order mode is the same, taking the single working principle as an example:

[0070] Referring to the attached Figures 10-14 When the piezoelectric bimorph cantilever beam 5 is vibrated downward by the upper and lower piezoelectric chips, the volume of the pump cavity between the upper piezoelectric chip and the inner layer plate of the upper side Tesla flow channel increases, a negative pressure is generated, and external gas enters the upper side pump cavity through the inlet opening formed in the outer layer plate of the upper side Tesla flow channel, the Tesla flow channel and the pump cavity inlet hole in sequence (the arrow direction indicates the gas flow direction, the large arrow indicates that the gas flow amount is large, and the small arrow indicates that the gas flow amount is small), thereby realizing the air inlet process;

[0071] Referring to the attached Figure 11 When the piezoelectric bimorph cantilever beam 5 is vibrated downward by the upper and lower piezoelectric chips, the volume of the pump cavity between the upper piezoelectric chip and the inner layer plate of the upper side Tesla flow channel increases, a negative pressure is generated, and external gas enters the upper side pump cavity through the inlet opening formed in the outer layer plate of the upper side Tesla flow channel, the Tesla flow channel and the pump cavity inlet hole in sequence (the arrow direction indicates the gas flow direction, the large arrow indicates that the gas flow amount is large, and the small arrow indicates that the gas flow amount is small), thereby realizing the air inlet process;

[0072] At the same time, the volume of the pump cavity between the lower piezoelectric wafer and the inner layer plate of the lower side Tesla flow channel is reduced, the air pressure is increased, the gas is pumped out, most of the gas is directly ejected to the outside of the pump body through the lower outflow port, and a small part of the gas enters the lower side Tesla flow channel along the lower side pump cavity inflow hole. However, due to the geometric characteristics of the Tesla valve, when the fluid flows in the opposite direction, the Tesla valve flow channel will form a complex vortex, preventing the fluid from flowing back, so that the reverse cut-off is realized; the principle is the same when the piezoelectric bimorph cantilever beam 5 vibrates upward, and the fluid flow condition is shown in the accompanying Figure 12 With the up-and-down vibration of the piezoelectric bimorph cantilever beam 5, the piezoelectric bimorph cantilever beam 5 valve-free ultrasonic gas pump array working in the second-order mode can realize continuous pumping of the gas.

[0073] In summary, the device can realize the transfer of fluid (upward and downward suction, and discharge on both sides), and remarkable effects will be achieved when it is applied to the heat dissipation of precision machinery.

Claims

1. A piezoelectric bimorph cantilever beam valveless ultrasonic air pump operating in the second order mode, characterized in that, The utility model relates to a two-dimensional array of piezoelectric bimorph cantilever beam valveless ultrasonic air pumps working in the second order mode, comprising: a Tesla flow channel outer plate (1), a Tesla flow channel inner plate (2), a cantilever beam composite plate (4), and an outer partition plate (7); the Tesla flow channel outer plate (1) is provided with an inflow port (9) of the Tesla flow channel in the middle, and the Tesla flow channel inner plate (2) is provided with pump cavity inflow holes (10) on both sides; the cantilever beam composite plate (4) is composed of a middle straight beam and cantilever beams and fixing plates (3) symmetrically arranged on the left and right sides of the middle straight beam; the upper and lower sides of the middle straight beam are fixedly connected with the fixing plates (3); piezoelectric chips are adhered to the two sides of the cantilever beam to form piezoelectric bimorph cantilever beams (5); the upper and lower fixing plates (3) are sequentially and sealingly fixed with the Tesla flow channel inner plate (2) and the Tesla flow channel outer plate (1); then the left and right ends are closed by the outer partition plate (7); two double-layer pump cavities (15) are formed in left-right symmetry; an outflow port (16) is arranged on the opposite side of the middle straight beam of the pump cavity (15); after the Tesla flow channel outer plate (1) and the Tesla flow channel inner plate (2) are sealingly and fixedly connected, two Tesla flow channels in left-right symmetry are formed; fluid passes through the inflow port (9), the Tesla flow channel, the pump cavity inflow holes (10), the pump cavity (15), and is discharged from the outflow port (16).

2. A piezoelectric bimorph cantilever beam valveless ultrasonic air pump array operating in the second order mode, characterized in that: The utility model relates to a two-dimensional array of piezoelectric bimorph cantilever beam valveless ultrasonic air pumps working in the second order mode, comprising:

3. The piezoelectric bimorph cantilever beam valveless ultrasonic gas pump array operating in the second order mode according to claim 1 or 2, characterized in that: the piezoelectric bimorph cantilever beam (5) vibrates in the second order mode when working, and the vibration frequency is in the ultrasonic segment.

4. The piezoelectric bimorph cantilever beam valveless ultrasonic gas pump array operating in the second order mode of claim 3, wherein: the pump cavity inflow holes (10) are arranged at the center position of a local deformation gradient secondary small area (17) of the piezoelectric bimorph cantilever beam when working.

5. The piezoelectric bimorph cantilever beam valveless ultrasonic gas pump array operating in the second order mode of claim 4, wherein: the Tesla flow channel (8) is perpendicular to the axes of the inflow port (9) and the pump cavity inflow hole (10) connected therewith.

6. The two-dimensional array of piezoelectric bimorph cantilever beam valveless ultrasonic air pumps working in the second order mode according to claim 5, characterized in that: the left-right symmetric Tesla flow channels (8) are arranged in an "X shape", the inflow port (9) is connected to four Tesla flow channel units inward, and the end of each Tesla flow channel unit is connected to a corresponding pump cavity (15) through a pump cavity inflow hole (10).

7. A method for using the two-dimensional array of piezoelectric bimorph cantilever beam valveless ultrasonic air pumps working in the second order mode, characterized in that: 1) the two-dimensional array of piezoelectric bimorph cantilever beam valveless ultrasonic air pumps working in the second order mode according to claim 2 is installed on the surface of a component and in the gap thereof; 2) opposite-phase alternating-current signals are applied to the upper and lower piezoelectric chips of the multiple piezoelectric bimorph cantilever beams to make them ultrasonically vibrate in the second order mode; 3) the piezoelectric bimorph cantilever beams are dynamically activated and loaded by a controller; 4) the piezoelectric bimorph cantilever beams reciprocate up and down to realize rapid upward and downward suction of fluid and discharge of fluid from both sides, thereby cooling the component.

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