A new type of piezoelectric micro pump

Abstract

The invention discloses a novel piezoelectric micropump, which comprises a pump casing, a piezoelectric element, a substrate, a flexible plate and a bottom plate. The pump casing is an insulator, and the pump casing, the substrate, the flexible plate and the bottom plate are sealed and connected in sequence. The pump casing, the substrate and the flexible plate form a pump cavity, and the piezoelectric element is installed on the substrate. The invention is scientific and reasonable, safe and convenient to use, and is provided with a double-beam symmetrical cantilever and a second annular protrusion. The double-beam symmetrical cantilever is evenly distributed, which can effectively reduce the vibration modal distortion of the piezoelectric micropump during operation. At the same time, the second annular protrusion is arranged at the bending vibration node of the flexible plate, which can also effectively reduce the vibration modal distortion of the piezoelectric micropump during operation. At the same time, the second annular protrusion is added to suppress the self-excited resonance of the flexible plate in the fluid, has a noise reduction function, and can effectively extend the service life of the piezoelectric micropump.

Description

Technical Field

[0001] The invention relates to the technical field of fluid transportation, in particular to a novel piezoelectric micro pump. Background Art

[0002] Piezoelectric pumps use the inverse piezoelectric effect of piezoelectric ceramics to deform the piezoelectric vibrator, and the deformation then produces a volume change in the pump chamber to achieve fluid delivery or use the piezoelectric vibrator to generate waves to deliver fluid. Piezoelectric pumps have the characteristics of simple structure, fast response speed, small size, no noise, high pressure, high head, no pressure relief, no pollution, easy installation and use. With the gradual improvement of piezoelectric pump technology, the size of piezoelectric pumps has gradually decreased, and various types of piezoelectric micropumps have been launched and are widely used in medical, chemical analysis and other fields.

[0003] The Chinese patents related to piezoelectric micropumps that have been published mainly focus on how to improve output performance and how to reduce volume. There is little attention paid to the service life of piezoelectric micropumps, while there is a significant demand for the life of piezoelectric micropumps in application fields such as medical treatment, chemical analysis, and automotive electronics. The technical solutions published by Chinese patents CN101490419B, CN102597520B, and CA106296241A, etc., use cantilever to constrain the bending deformation part, and the bending deformation part is directly opposite to the resonant part, and the resonant part is provided with an air intake hole. This type of piezoelectric micropump has a service life of about 600 hours. Due to fatigue fracture of the cantilever beam and fatigue damage around the air intake hole, the micropump is eventually damaged. Summary of the invention

[0004] The purpose of the present invention is to provide a novel piezoelectric micro pump to solve the problems raised in the prior art.

[0005] To achieve the above-mentioned purpose, the present invention provides the following technical solutions: a novel piezoelectric micropump, comprising a pump housing, a piezoelectric element, a substrate, a flexible plate and a bottom plate, wherein the pump housing is an insulator, the pump housing, the substrate, the flexible plate and the bottom plate are sealed and connected in sequence, the pump housing, the substrate and the flexible plate form a pump cavity, a substrate is mounted on the lower surface of the pump housing, the substrate is a conductor, a flexible plate is mounted on a side of the substrate away from the pump housing, a bottom plate is mounted on a side of the flexible plate away from the substrate, a piezoelectric element is mounted on a side of the substrate close to the pump housing, the piezoelectric element is located in the pump cavity and does not contact the pump housing;

[0006] The pump housing includes an air outlet, a recess and a first electrode;

[0007] A depression is provided on one side of the pump housing close to the piezoelectric element, and an air outlet is provided in the depression through the housing. A first electrode is installed on the side wall of the housing that penetrates the housing from the inside to the outside. The end of the first electrode located in the pump cavity is connected to the piezoelectric element and the bending vibration node of the deformation zone, and the first electrode is a conductor.

[0008] As a preferred technical solution, the substrate includes a deformation zone, an outer frame, a double-beam symmetrical cantilever, a first flow channel and a second electrode;

[0009] The edge of the deformation zone is connected to the outer frame through a plurality of double-beam symmetrical cantilevers, and the plurality of double-beam symmetrical cantilevers are evenly distributed in the gap between the deformation zone and the outer frame. The even distribution of the plurality of double-beam symmetrical cantilevers can reduce vibration modal distortion. A first flow channel extending to the edge of the deformation zone is provided on a side of the deformation zone away from the piezoelectric element. A second electrode is installed on the edge of the outer frame, and the second electrode is located outside the pump cavity.

[0010] The double-beam symmetrical cantilever comprises a beam portion and a connecting portion;

[0011] The beam part is connected to two separated connecting parts in the deformation zone, and the beam part relatively extends along the outer periphery of the deformation zone in the gap between the deformation zone and the outer frame, with the same extension length, and the ends of the beam part are respectively connected to the outer frame through the connecting parts.

[0012] As a preferred technical solution, the connections between the beam and the connecting part, the connecting part and the deformation zone, and the connecting part and the outer frame are all transitioned with rounded corners, and the width of the connecting part is greater than the width of the beam part. By transitioning with rounded corners at the connection and increasing the width of the connection part, stress concentration at the root of the cantilever can be reduced and the life of the piezoelectric micropump can be extended.

[0013] As a preferred technical solution, the substrate also includes a first double-slope protrusion, and the first flow channel is provided with a first double-slope protrusion. The slope of the first double-slope protrusion close to the center slope of the deformation zone is smaller than the slope of the slope away from the center slope of the deformation zone. This structure can effectively prevent fluid backflow.

[0014] As a preferred technical solution, the flexible plate includes an air inlet, a first annular protrusion, a second annular protrusion and an avoidance groove;

[0015] An air inlet penetrating the flexible plate is provided at the position of maximum displacement of the flexible bending deformation, and a plurality of avoidance grooves penetrating the flexible plate are provided at equal distances on the edge of the flexible plate, the avoidance grooves are directly opposite to the beam portion of the substrate, and the avoidance grooves allow the beam portion to enter the avoidance grooves during vibration without contacting the flexible plate, thereby reducing noise generated by contact and collision, and a first annular protrusion is installed on a surface of the flexible plate away from the piezoelectric element, close to the edge of the air inlet, and a second annular protrusion is installed on the outer side of the first annular protrusion, and the second annular protrusion is located at the bending vibration node of the flexible plate.

[0016] As a preferred technical solution, the flexible plate also includes a second double-slope protrusion. The second double-slope protrusion is arranged on one side of the flexible plate close to the piezoelectric element. The slope of the second double-slope protrusion close to the center slope of the air inlet is smaller than the slope of the slope away from the center slope of the air inlet, which can effectively prevent fluid backflow.

[0017] As a preferred technical solution, the bottom plate includes an inner concave portion, a second flow channel, air holes and grooves;

[0018] An inner concave portion is provided on one surface of the bottom plate close to the flexible plate, and a plurality of second flow channels are opened in the inner concave portion along the boundary tangent direction to the outer periphery of the bottom plate, and air holes are opened through one end of the plurality of second flow channels close to the outer periphery of the bottom plate. After the fluid flows into the inner concave portion from the second flow channel, a low-frequency eddy current is formed, and the frequency is much lower than the operating frequency of the piezoelectric micropump, and no self-excited resonance or noise is generated. At the same time, the low-frequency eddy current with angular momentum can prevent the backflow of the fluid. A groove is also opened on the edge of one side of the bottom plate close to the flexible plate. The groove is equal in size to the avoidance groove and is arranged directly opposite to the avoidance groove, and the groove is not connected to the inner concave portion.

[0019] As a preferred technical solution, the first flow channel is an annular flow channel.

[0020] As a preferred technical solution, the connections between the beam and the connecting part, the connecting part and the deformation zone, and the connecting part and the outer frame are all transitioned with rounded corners, the width of the connecting part is greater than the width of the beam, the length of the beam is greater than its width, and the width of the beam is greater than its thickness. By transitioning with rounded corners at the connection and increasing the width of the connection, stress concentration at the root of the cantilever can be reduced and the life of the piezoelectric micropump can be extended.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] 1. A double-beam symmetrical cantilever and a second annular protrusion are provided. The uniform distribution of several double-beam symmetrical cantilevers can effectively reduce the vibration modal distortion of the piezoelectric micropump during operation. At the same time, the second annular protrusion is provided at the bending vibration node of the flexible plate, which can also effectively reduce the vibration modal distortion of the piezoelectric micropump during operation. At the same time, the addition of the second annular protrusion can suppress the self-excited resonance of the flexible plate in the fluid, has a noise reduction function, and can effectively extend the service life of the piezoelectric micropump. Since the beam and the connecting part, the connecting part and the deformation zone, and the connecting part and the outer frame are connected with rounded corners, the width of the connecting part is greater than the width of the beam, which can effectively reduce the stress concentration at the root of the arm, and further extend the service life of the piezoelectric micropump.

[0023] 2. The first double-slope protrusion arranged on the side of the deformation zone away from the piezoelectric element and the second double-slope protrusion arranged on the side of the flexible plate away from the first annular protrusion can effectively prevent the fluid from flowing back.

[0024] 3. The inner concave portion, the second flow channel, the air holes and the grooves are provided, so that the fluid can form a low-frequency eddy current after flowing into the inner concave portion from the second flow channel, and the frequency is much lower than the operating frequency of the piezoelectric micropump, so no self-excited resonance will be generated, and no noise will be generated. At the same time, the low-frequency eddy current with angular momentum can prevent the fluid from flowing back. Through the multiple avoidance grooves opened on the edge of the flexible plate and the grooves arranged on the bottom plate opposite to the avoidance grooves, the beam can enter the avoidance grooves and the grooves when vibrating without contacting the flexible plate and the bottom plate, which can effectively reduce the noise generated by contact and collision. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a schematic diagram of the structure of a novel piezoelectric micro pump of the present invention;

[0026] Figure 2 A forward exploded structural diagram of a novel piezoelectric micro pump of the present invention having a first double-slope protrusion;

[0027] Figure 3 A reverse exploded structural diagram of a novel piezoelectric micro pump of the present invention having a first double slope protrusion;

[0028] Figure 4 A forward exploded structural diagram of a novel piezoelectric micro pump of the present invention having a second double-slope protrusion;

[0029] Figure 5 A reverse exploded structural diagram of a novel piezoelectric micro pump of the present invention having a second double slope protrusion;

[0030] Figure 6 This is a structural cross-sectional view of a novel piezoelectric micro pump of the present invention;

[0031] Figure 7 This is a schematic diagram of the structure of a novel piezoelectric micro pump substrate of the present invention;

[0032] Figure 8 For the present invention Figure 7 Schematic diagram of the enlarged structure of the middle double-beam symmetrical cantilever;

[0033] Fig. 9 This is a schematic diagram of an ideal support for a novel piezoelectric micro pump of the present invention;

[0034] Fig.10 A schematic diagram of a novel piezoelectric micropump arm of the present invention in Cartesian coordinates;

[0035] Fig.11 A schematic diagram of a substrate supporting a deformation zone of a novel piezoelectric micropump in the XOZ plane according to the present invention;

[0036] Fig.12 This is a schematic diagram of a substrate support method in an XOY plane for a novel piezoelectric micropump of the present invention.

[0037] Numbers in the figure: 1, pump housing; 101, air outlet; 102, recess; 103, first electrode;

[0038] 2. Piezoelectric element;

[0039] 3. substrate; 301. deformation zone; 302. outer frame;

[0040] 303, double beam symmetrical cantilever; 3031, beam portion; 3032, connecting portion;

[0041] 304, first flow channel; 305, second electrode;

[0042] 4. flexible plate; 401. air inlet; 402. first annular protrusion; 403. second annular protrusion; 404. avoidance groove;

[0043] 5. bottom plate; 501. inner concave portion; 502. second flow channel; 503. air hole; 504. groove;

[0044] 6. Pump chamber. DETAILED DESCRIPTION

[0045] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0046] like Fig. 9 As shown, the support mode of the deformation zone 301 is a simple support with wave nodes as fulcrums (A and B are wave node positions). The deformation zone 301 only produces bending deformation under this support mode. The deformation zone 301 has no translation in the xoy plane, no rotation around the z axis, and rotation around the x and y axes. The edge of the deformation zone 301 has translation along the z axis. In actual situation, the deformation zone 301 is connected to the outer frame 302 through a plurality of double-beam symmetrical cantilevers 303, and the plurality of double-beam symmetrical cantilevers 303 are evenly distributed around the deformation zone 301. The influence of the curvature of the double-beam symmetrical cantilever 303 is ignored, and the deformed part of the double-beam symmetrical cantilever 303 is equivalent to a straight cantilever beam with a rectangular cross-section.

[0047] like Fig.10 As shown, the length of the straight cantilever beam is L, the thickness is h, the width is b, the Young's modulus of the cantilever material is E, and the equivalent stiffness of the straight cantilever beam in the three directions along the Cartesian coordinate system is and The sizes are:

[0048] The driving module composed of the deformation zone 301, the double-beam symmetrical cantilever 303 and the piezoelectric element 2 is equivalent to a spring-mass system;

[0049] like Figure 11-12 As shown, the translational equivalent stiffness of the xoy plane is Equivalent torsional stiffness around the x-axis or y-axis Equivalent translational stiffness in the z-axis direction Equivalent torsional stiffness around the z-axis In order to approach the ideal condition as much as possible, the translational equivalent stiffness in the xoy plane and the equivalent torsional stiffness around the z-axis need to be very large, and the translational equivalent stiffness in the z-axis direction and the equivalent torsional stiffness around the x-axis or y-axis need to be very small. Then: L>>b>h, that is, the length of the beam 3031 is much larger than its width, and the width of the beam 3031 is larger than its thickness. The closer to the ideal condition, the more stable the vibration mode.

[0050] Embodiment 1: Figure 1-3 , 6-8, the present invention provides a novel piezoelectric micro pump, the piezoelectric micro pump comprises a pump housing 1, a piezoelectric element 2, a substrate 3, a flexible plate 4 and a bottom plate 5, the pump housing 1 is an insulator, the pump housing 1, the substrate 3, the flexible plate 4 and the bottom plate 5 are sealed and connected in sequence, the pump housing 1, the substrate 3, the flexible plate 4 surround a pump cavity 6, the substrate 3 is mounted on the lower surface of the pump housing 1, the substrate 3 is a conductor, the flexible plate 4 is mounted on the side of the substrate 3 away from the pump housing 1, the bottom plate 3 is mounted on the side of the flexible plate 4 away from the substrate 3, the piezoelectric element 2 is mounted on the side of the substrate 3 close to the pump housing 1, the piezoelectric element 2 is located in the pump cavity 6 and does not contact the pump housing 1;

[0051] The pump housing 1 includes an air outlet 101, a recess 102 and a first electrode 103;

[0052] A recess 102 is provided on one side of the pump housing 1 close to the piezoelectric element 2. The recess 102 is used to form a pump chamber 6 inside the micropump for fluid transportation. The recess 102 penetrates the housing 1 to provide an air outlet 101. A first electrode 103 is installed on the side wall of the housing 1 and penetrates the housing 1 from the inside to the outside. The end of the first electrode 103 located in the pump chamber 6 is connected to the bending vibration node between the piezoelectric element 2 and the deformation zone 301. The first electrode 103 is a conductor.

[0053] The substrate 3 includes a deformation area 301, an outer frame 302, a double-beam symmetrical cantilever 303, a first flow channel 304 and a second electrode 305;

[0054] The edge of the deformation zone 301 is connected to the outer frame 302 through a plurality of double-beam symmetrical cantilevers 303, and the double-beam symmetrical cantilevers 303 are evenly distributed in the gap between the deformation zone 301 and the outer frame 302, and are used to reduce vibration modal distortion. A first flow channel 304 extending to the edge of the deformation zone 301 is provided on one side of the deformation zone 301 away from the piezoelectric element 2, and the first flow channel 304 is an annular flow channel. A second electrode 305 is installed on the edge of the outer frame 302, and the first electrode 103 and the second electrode 305 are used to provide a power source for the micro pump, and the second electrode 305 is located outside the pump cavity 6;

[0055] The double-beam symmetrical cantilever 303 includes a beam portion 3031 and a connecting portion 3032;

[0056] The beam portion 3031 is connected to two separate connecting portions 3032 of the deformation zone 301. The beam portion 3031 relatively extends along the outer periphery of the deformation zone 301 in the gap between the deformation zone 301 and the outer frame 302, and the extension length is the same. The ends of the beam portion 3031 are respectively connected to the outer frame 302 through the connecting portions 3032. The beam portion 3031 is used to cooperate with the connecting portion 3032 to connect the deformation zone 301 and the outer frame 302. The connections between the beam portion 3031 and the connecting portion 3032, the connecting portion 3032 and the deformation zone 301, and the connecting portion 3032 and the outer frame 302 are all transitioned with rounded corners. The width of the connecting portion 3032 is greater than the width of the beam portion 3031, the length of the beam portion 3031 is greater than its width, and the width of the beam portion 3031 is greater than its thickness. By utilizing the rounded corner transition and improving the bending stiffness, the stress concentration at the root of the double-beam symmetrical cantilever 303 is reduced, and the service life of the piezoelectric micropump is extended.

[0057] The substrate 3 also includes a first double-slope protrusion 306, which is arranged on the first flow channel 304. The slope of the first double-slope protrusion 306 close to the central slope of the deformation zone 301 is smaller than the slope of the central slope away from the deformation zone 301, so as to prevent the piezoelectric micropump from backflowing when transporting fluid.

[0058] The flexible plate 4 includes an air inlet 401, a first annular protrusion 402, a second annular protrusion 403 and an avoidance groove 404;

[0059] An air inlet 401 penetrating the flexible plate 4 is provided at the position of the maximum displacement of the bending deformation of the flexible plate 4, and a plurality of avoidance grooves 404 penetrating the flexible plate are provided at equal distances on the edge of the flexible plate 4, so that the beam portion 3031 enters the avoidance groove 404 during vibration, so that the beam portion 3031 does not contact the flexible plate 4, thereby reducing the noise generated by the contact, and a first annular protrusion 402 is installed on the side of the flexible plate 4 away from the piezoelectric element 2, close to the edge of the air inlet 401, and a second annular protrusion 403 is installed on the outside of the first annular protrusion 402, and the second annular protrusion 403 is located at the bending vibration node of the flexible plate 4. The second annular protrusion 403 can effectively reduce the vibration modal distortion during the operation of the piezoelectric micropump. At the same time, the addition of the second annular protrusion 403 can suppress the self-excited resonance of the flexible plate 4 in the fluid, has a noise reduction function, and can effectively extend the service life of the piezoelectric micropump.

[0060] The bottom plate 5 includes an inner concave portion 501, a second flow channel 502, an air hole 503 and a groove 504;

[0061] An inner recess 501 is provided on one surface of the bottom plate 5 close to the flexible plate 4, and a plurality of second flow channels 502 are provided on the inner recess 501 along the boundary tangent direction to the outer periphery of the bottom plate 5, and air holes 503 are provided through one end of the plurality of second flow channels 502 close to the outer periphery of the bottom plate 5. A groove 504 is also provided on one edge of the bottom plate 5 close to the flexible plate 4, and the groove 504 is equal in size to the avoidance groove 404 and is arranged directly opposite to the avoidance groove 404, and the groove 504 is not connected to the inner recess 501.

[0062] Embodiment 2: Figure 1 , 4 -8, a novel piezoelectric micro pump of this embodiment is basically the same as the embodiment 1, except that: the first double-slope protrusion 306 is not provided inside the first flow channel 304 of the deformation zone 301, and a second double-slope protrusion 405 is provided on the side of the flexible plate 4 close to the piezoelectric element 2 to prevent the backflow of the fluid;

[0063] The present invention provides a novel piezoelectric micropump, which comprises a pump housing 1, a piezoelectric element 2, a substrate 3, a flexible plate 4 and a bottom plate 5. The pump housing 1 is an insulator. The pump housing 1, the substrate 3, the flexible plate 4 and the bottom plate 5 are sealed and connected in sequence. The pump housing 1, the substrate 3 and the flexible plate 4 form a pump cavity 6. The substrate 3 is installed on the lower surface of the pump housing 1. The substrate 3 is a conductor. The flexible plate 4 is installed on the side of the substrate 3 away from the pump housing 1. The bottom plate 3 is installed on the side of the flexible plate 4 away from the substrate 3. The piezoelectric element 2 is installed on the side of the substrate 3 close to the pump housing 1. The piezoelectric element 2 is located in the pump cavity 6 and does not contact the pump housing 1.

[0064] The pump housing 1 includes an air outlet 101, a recess 102 and a first electrode 103;

[0065] A recess 102 is provided on one side of the pump housing 1 close to the piezoelectric element 2. The recess 102 is used to form a pump chamber 6 inside the micropump for fluid transportation. The recess 102 penetrates the housing 1 to provide an air outlet 101. A first electrode 103 is installed on the side wall of the housing 1 and penetrates the housing 1 from the inside to the outside. The end of the first electrode 103 located in the pump chamber 6 is connected to the bending vibration node between the piezoelectric element 2 and the deformation zone 301. The first electrode 103 is a conductor.

[0066] The substrate 3 includes a deformation area 301, an outer frame 302, a double-beam symmetrical cantilever 303, a first flow channel 304 and a second electrode 305;

[0067] The edge of the deformation zone 301 is connected to the outer frame 302 through a plurality of double-beam symmetrical cantilevers 303, and the double-beam symmetrical cantilevers 303 are evenly distributed in the gap between the deformation zone 301 and the outer frame 302, and are used to reduce vibration modal distortion. A first flow channel 304 extending to the edge of the deformation zone 301 is provided on one side of the deformation zone 301 away from the piezoelectric element 2, and the first flow channel 304 is an annular flow channel. A second electrode 305 is installed on the edge of the outer frame 302, and the first electrode 103 and the second electrode 305 are used to provide a power source for the micro pump, and the second electrode 305 is located outside the pump cavity 6;

[0068] The double-beam symmetrical cantilever 303 includes a beam portion 3031 and a connecting portion 3032;

[0069] The beam portion 3031 is connected to two separate connecting portions 3032 of the deformation zone 301. The beam portion 3031 relatively extends along the outer periphery of the deformation zone 301 in the gap between the deformation zone 301 and the outer frame 302, and the extension length is the same. The ends of the beam portion 3031 are respectively connected to the outer frame 302 through the connecting portions 3032. The beam portion 3031 is used to cooperate with the connecting portion 3032 to connect the deformation zone 301 and the outer frame 302. The connections between the beam portion 3031 and the connecting portion 3032, the connecting portion 3032 and the deformation zone 301, and the connecting portion 3032 and the outer frame 302 are all transitioned with rounded corners. The width of the connecting portion 3032 is greater than the width of the beam portion 3031, the length of the beam portion 3031 is greater than its width, and the width of the beam portion 3031 is greater than its thickness. The rounded corner transition and bending stiffness are used to reduce the stress concentration at the root of the double-beam symmetrical cantilever 303, and extend the service life of the piezoelectric micropump.

[0070] The substrate 3 also includes a first double-slope protrusion 306, which is arranged on the first flow channel 304. The slope of the first double-slope protrusion 306 close to the central slope of the deformation zone 301 is smaller than the slope of the central slope away from the deformation zone 301, so as to prevent the piezoelectric micropump from backflowing when transporting fluid.

[0071] The flexible plate 4 includes an air inlet 401, a first annular protrusion 402, a second annular protrusion 403 and an avoidance groove 404;

[0072] An air inlet 401 penetrating the flexible plate 4 is provided at the position of the maximum displacement of the bending deformation of the flexible plate 4, and a plurality of avoidance grooves 404 penetrating the flexible plate are provided at equal distances on the edge of the flexible plate 4, so that the beam portion 3031 enters the avoidance groove 404 during vibration, so that the beam portion 3031 does not contact the flexible plate 4, thereby reducing the noise generated by the contact, and a first annular protrusion 402 is installed on the side of the flexible plate 4 away from the piezoelectric element 2, close to the edge of the air inlet 401, and a second annular protrusion 403 is installed on the outside of the first annular protrusion 402, and the second annular protrusion 403 is located at the bending vibration node of the flexible plate 4. The second annular protrusion 403 can effectively reduce the vibration modal distortion during the operation of the piezoelectric micropump. At the same time, the addition of the second annular protrusion 403 can suppress the self-excited resonance of the flexible plate 4 in the fluid, has a noise reduction function, and can effectively extend the service life of the piezoelectric micropump.

[0073] The flexible plate 4 also includes a second double-slope protrusion 405. The second double-slope protrusion 405 is arranged on one side of the flexible plate 4 close to the piezoelectric element 2. The slope of the second double-slope protrusion 405 close to the center slope of the air inlet 401 is greater than the slope of the slope away from the center slope of the air inlet 401, which can effectively prevent fluid backflow.

[0074] The bottom plate 5 includes an inner concave portion 501, a second flow channel 502, an air hole 503 and a groove 504;

[0075] An inner recess 501 is provided on one surface of the bottom plate 5 close to the flexible plate 4, and a plurality of second flow channels 502 are provided on the inner recess 501 along the boundary tangent direction to the outer periphery of the bottom plate 5, and air holes 503 are provided through one end of the plurality of second flow channels 502 close to the outer periphery of the bottom plate 5. A groove 504 is also provided on one edge of the bottom plate 5 close to the flexible plate 4, and the groove 504 is equal in size to the avoidance groove 404 and is arranged directly opposite to the avoidance groove 404, and the groove 504 is not connected to the inner recess 501.

[0076] In summary: the service life and stability of the piezoelectric micropump can be improved through a simple structure, backflow can be prevented, and the noise during the use of the piezoelectric micropump can be effectively reduced.

[0077] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other specific forms without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations falling within the meaning and scope of the equivalent elements of the claims be included in the invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

Claims

1. A novel piezoelectric micropump, characterized in that: The piezoelectric micro pump comprises a pump housing (1), a piezoelectric element (2), a substrate (3), a flexible plate (4) and a bottom plate (5); the pump housing (1) is an insulator; the pump housing (1), the substrate (3), the flexible plate (4) and the bottom plate (5) are sealed and connected in sequence; the pump housing (1), the substrate (3) and the flexible plate (4) form a pump cavity (6); and the substrate (3) is mounted on the lower surface of the pump housing (1); The substrate (3) comprises a deformation zone (301), an outer frame (302), a double-beam symmetrical cantilever (303), a first flow channel (304) and a second electrode (305); The edge of the deformation zone (301) is connected to the outer frame (302) via a plurality of double-beam symmetrical cantilevers (303), and the plurality of double-beam symmetrical cantilevers (303) are evenly distributed in the gap between the deformation zone (301) and the outer frame (302). A first flow channel (304) extending to the edge of the deformation zone (301) is provided on a side of the deformation zone (301) away from the piezoelectric element (2). A second electrode (305) is installed on the edge of the outer frame (302), and the second electrode (305) is located outside the pump chamber (6). The deformation zone (301) is in the shape of a circular plate. The double-beam symmetrical cantilever (303) comprises two beam portions (3031) symmetrically arranged in pairs and connecting portions (3032) arranged at both ends of a single beam portion; The two beams (3031) are symmetrically arranged in pairs and connected to two separate connecting portions (3032) of the deformation zone (301). The two beams (3031) extend relatively in the circumferential direction along the outer circumference of the deformation zone (301) in the gap between the deformation zone (301) and the outer frame (302). The extension lengths are the same. The ends of the beams (3031) are respectively connected to the outer frame (302) through the separate connecting portions (3032). The two beams (3031) are used to cooperate with each other to connect. The connection portion (3032) connects the deformation zone (301) and the outer frame (302); the substrate (3) is a conductor; a flexible plate (4) is installed on a side of the substrate (3) away from the pump housing (1); a bottom plate (5) is installed on a side of the flexible plate (4) away from the substrate (3); a piezoelectric element (2) is installed on a side of the substrate (3) close to the pump housing (1); the piezoelectric element (2) is in the shape of a circular plate; the piezoelectric element (2) is located in the pump cavity (6) and does not contact the pump housing (1); The pump housing (1) comprises an air outlet (101), a recess (102) and a first electrode (103); A depression (102) is provided on one side of the pump housing (1) close to the piezoelectric element (2), and an air outlet (101) is provided in the depression (102) and passes through the pump housing (1). A first electrode (103) is installed on the side wall of the pump housing (1) and passes through the pump housing (1) from the inside to the outside, and the first electrode (103) is a conductor.

2. A novel piezoelectric micropump according to claim 1, characterized in that: The substrate (3) further comprises a first double-slope protrusion (306), the first flow channel (304) is provided with the first double-slope protrusion (306), and the slope of the first double-slope protrusion (306) close to the central slope of the deformation zone (301) is smaller than the slope of the central slope away from the deformation zone (301).

3. A novel piezoelectric micro pump according to claim 1, characterized in that: The flexible plate (4) comprises an air inlet (401), a first annular protrusion (402), a second annular protrusion (403) and an avoidance groove (404); An air inlet (401) penetrating the flexible plate (4) is provided at the position of maximum displacement of the bending deformation of the flexible plate (4); a plurality of avoidance grooves (404) penetrating the flexible plate are provided at equal intervals on the edge of the flexible plate (4); a first annular protrusion (402) is installed on the side of the flexible plate (4) away from the piezoelectric element (2) in close contact with the edge of the air inlet (401); a second annular protrusion (403) is installed outside the first annular protrusion (402); and the second annular protrusion (403) is located at a bending vibration node of the flexible plate (4).

4. A novel piezoelectric micropump according to claim 3, characterized in that: The flexible plate (4) further comprises a second double-slope protrusion (405), and the second double-slope protrusion (405) is arranged on one side of the flexible plate (4) close to the piezoelectric element (2), and the slope of the second double-slope protrusion (405) close to the central slope of the air inlet (401) is smaller than the slope of the central slope away from the air inlet (401).

5. A novel piezoelectric micro pump according to claim 1, characterized in that: The bottom plate (5) comprises an inner recess (501), a second flow channel (502), air holes (503) and grooves (504); An inner concave portion (501) is provided on one side of the bottom plate (5) close to the flexible plate (4); a plurality of second flow channels (502) are provided on the inner concave portion (501) along the boundary tangent direction to the outer periphery of the bottom plate (5); air holes (503) are provided through one end of the plurality of second flow channels (502) close to the outer periphery of the bottom plate (5); a groove (504) is also provided on one side edge of the bottom plate (5) close to the flexible plate (4); the groove (504) is equal in size to the avoidance groove (404) and is arranged opposite to the avoidance groove (404); the groove (504) is not connected to the inner concave portion (501).

6. A novel piezoelectric micro pump according to claim 1, characterized in that: The first flow channel (304) is an annular flow channel.

7. A novel piezoelectric micro pump according to claim 1, characterized in that: The connections between the beam portion (3031) and the connecting portion (3032), the connecting portion (3032) and the deformation zone (301), and the connecting portion (3032) and the outer frame (302) are all transitioned with rounded corners; the width of the connecting portion (3032) is greater than the width of the beam portion (3031); the length of the beam portion (3031) is greater than its width; and the width of the beam portion (3031) is greater than its thickness.

8. A novel piezoelectric micro pump according to claim 1, characterized in that: The end of the first electrode (103) located in the pump chamber (6) is connected to the piezoelectric element (2) and the bending vibration node of the deformation zone (301).

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