US20090148318A1 - Piezoelectric Pump - Google Patents

Piezoelectric Pump Download PDF

Info

Publication number
US20090148318A1
US20090148318A1 US12/367,084 US36708409A US2009148318A1 US 20090148318 A1 US20090148318 A1 US 20090148318A1 US 36708409 A US36708409 A US 36708409A US 2009148318 A1 US2009148318 A1 US 2009148318A1
Authority
US
United States
Prior art keywords
opening
diaphragm
piezoelectric
portion
piezoelectric element
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Abandoned
Application number
US12/367,084
Inventor
Gaku Kamitani
Midori Sunaga
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Murata Manufacturing Co Ltd
Original Assignee
Murata Manufacturing Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority to JP2006332692 priority Critical
Priority to JP2006-332692 priority
Priority to PCT/JP2007/073555 priority patent/WO2008069264A1/en
Application filed by Murata Manufacturing Co Ltd filed Critical Murata Manufacturing Co Ltd
Assigned to MURATA MANUFACTURING CO., LTD. reassignment MURATA MANUFACTURING CO., LTD. ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: KAMITANI, GAKU, SUNAGA, MIDORI
Publication of US20090148318A1 publication Critical patent/US20090148318A1/en
Application status is Abandoned legal-status Critical

Links

Images

Classifications

    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04BPOSITIVE DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
    • F04B43/00Machines, pumps, or pumping installations having flexible working members
    • F04B43/02Machines, pumps, or pumping installations having flexible working members having plate-like flexible members, e.g. diaphragms
    • F04B43/04Pumps having electric drive
    • F04B43/043Micropumps
    • F04B43/046Micropumps with piezo-electric drive
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04BPOSITIVE DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
    • F04B43/00Machines, pumps, or pumping installations having flexible working members
    • F04B43/02Machines, pumps, or pumping installations having flexible working members having plate-like flexible members, e.g. diaphragms
    • F04B43/04Pumps having electric drive
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04BPOSITIVE DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
    • F04B45/00Pumps or pumping installations having flexible working members and specially adapted for elastic fluids
    • F04B45/04Pumps or pumping installations having flexible working members and specially adapted for elastic fluids having plate-like flexible members, e.g. diaphragms

Abstract

A piezoelectric pump having a first opening in a center portion of a pump body, and a second opening apart from the center. An outer peripheral portion of a metal diaphragm is fixed to the pump body, and a piezoelectric element having a size that covers the first opening and does not cover the second opening is bonded to a back center portion of the diaphragm. By applying a voltage near the resonance frequency to the piezoelectric element, a portion of the diaphragm opposing the first opening and a portion of the diaphragm opposing the second opening are bent in opposite directions so that fluid is drawn in from one of the first opening and the second opening and is discharged from the other opening. Such a piezoelectric pump can increase the discharging pressure, and can reliably discharge the fluid even under a condition where the pressure on the discharging side is high.

Description

    CROSS REFERENCE TO RELATED APPLICATIONS
  • The present application is a continuation of International Application No. PCT/JP2007/073555, filed Dec. 6, 2007, which claims priority to Japanese Patent Application No. JP2006-332692, filed Dec. 9, 2006, the entire contents of each of these applications being incorporated herein by reference in their entirety.
  • FIELD OF THE INVENTION
  • The present invention relates to piezoelectric pumps, and more particularly, to a piezoelectric pump using a diaphragm that is bent by a piezoelectric element.
  • BACKGROUND OF THE INVENTION
  • Piezoelectric pumps are used as cooling pumps in small electronic devices, such as notebook personal computers, and fuel transportation pumps in fuel cells. A piezoelectric pump is a pump using a diaphragm that is bent by the application of voltage to a piezoelectric element, and has advantages of a simple structure, a low profile structure, and low power consumption. In a piezoelectric pump using a piezoelectric element as a driving source, check valves are respectively provided at an inlet and an outlet. However, reliability of the check valves is reduced with use for a long period, and the fluid is not sufficiently transported because of adhesion of foreign substances, such as dust, to the check valves. Further, when the piezoelectric element is driven at a high frequency, the check valves, to which foreign substances, such as dust, adhere, do not follow the driving, and transportation of the fluid is impossible.
  • Patent Documents 1 and 2 propose a piezoelectric pump in which a diaphragm is mounted in contact with a pump body having an inlet and an outlet and in which a plurality of piezoelectric elements are mounted on the diaphragm so as to be arranged from the inlet to the outlet. In this pump, the piezoelectric elements are sequentially driven from a piezoelectric element close to the inlet to a piezoelectric element close to the outlet, so that the diaphragm can be sequentially bent from the inlet toward the outlet so as to push out the fluid from the inlet toward the outlet. When the application of voltage to the piezoelectric elements is stopped, a channel between the inlet and the outlet is closed by restoration of the diaphragm. Therefore, it is possible to omit check valves from the inlet and the outlet.
  • Unfortunately, since a plurality of piezoelectric elements need to be arranged in a plane in the piezoelectric pump having this structure, the piezoelectric pump has a large size and a complicated structure. Moreover, a driving circuit for sequentially driving the piezoelectric elements is complicated, and this increases the cost.
  • Patent Document 3 discloses a fluid pump having no check valve. In a fluid pump disclosed particularly in FIG. 10 of Patent Document 3, a pump chamber is formed between a pump body and a diaphragm, a first opening is provided in a center portion of the pump body, a second opening is provided in a peripheral portion of the pump body, an elastic buffer is provided in the diaphragm, and the diaphragm is bent by causing the center portion of the diaphragm by another driving means to reciprocate. When the diaphragm opens the first opening, fluid is drawn into the pump chamber from the first opening. When the diaphragm closes the first opening, the buffer portion corresponding to the second openings is bent, and the fluid is discharged from the second openings by the elastic restoring force of the buffer portion.
  • In Patent Document 3, since the diaphragm is merely driven in a reciprocating manner by the single driving source, the structure is simple. However, since only the portion of the diaphragm opposing the first opening, that is, only the center portion of the diaphragm is displaced and the peripheral portion (buffer portion) of the diaphragm is bent after the displacement, the diaphragm needs to be formed of a soft material. This makes it impossible to increase the discharging pressure. For example, when the fluid is compressible fluid such as air, a very soft material, such as rubber or resin, needs to be used in order to elastically deform the buffer portion of the diaphragm, and the discharging pressure is decreased. As a result, the fluid sometimes cannot be reliably discharged under a condition that the pressure outside the pump chamber is high.
  • Patent Document 1: Japanese Unexamined Patent Application Publication No. 2-149778
  • Patent Document 2: Japanese Unexamined Patent Application Publication No. 4-86388
  • Patent Document 3: Japanese Unexamined Patent Application Publication (Translation of PCT application) No. 10-511165
  • SUMMARY OF THE INVENTION
  • Accordingly, an object of a preferred embodiment of the present invention is to provide a piezoelectric pump that has a simple structure and that can increase the discharging pressure.
  • In order to achieve the above object, the present invention provides a piezoelectric pump including a pump body; a diaphragm fixed at an outer peripheral portion to the pump body; a piezoelectric element bonded to a center portion of the diaphragm; a first opening provided in a portion of the pump body opposing the substantial center portion of the diaphragm; and a second opening provided in an intermediate region between the center portion and the outer peripheral portion of the diaphragm or in a portion of the pump body opposing the intermediate region. The diaphragm is formed by a metal plate, and the piezoelectric element has a size such as to cover the first opening and such as not to reach the second opening. A portion of the diaphragm opposing the first opening and a portion of the diaphragm opposing the second opening are bent in opposite directions by applying a voltage having a predetermined frequency to the piezoelectric element so that fluid is drawn in from one of the first opening and the second opening and is discharged from the other opening.
  • Unlike Patent Document 3 in which fluid is pushed out by using an elastic restoring force of the diaphragm itself, according to the present invention, a metal plate having a high Young's modulus is used as the diaphragm and the fluid is discharged by forcibly bending the diaphragm by the piezoelectric element. In particular, since the piezoelectric element has a size such as to cover the first opening and such as not to reach the second opening, the portion of the diaphragm opposing the first opening and the portion of the diaphragm opposing the second opening can be efficiently bent in opposite directions. For this reason, the discharging pressure can be increased, and the fluid can be reliably discharged even under a condition where the pressure on the discharging side is high. In particular, since the diaphragm is formed by the metal plate having a high Young's modulus, it can properly follow the piezoelectric element, and this allows operation at a high frequency.
  • While the frequency of the voltage applied to the piezoelectric element can be arbitrarily selected, it is preferable that the piezoelectric element be driven at a frequency near the resonance frequency of a displacement member defined by the diaphragm and the piezoelectric element, since the displacement volume of the diaphragm is quite large, and a high flow rate can be obtained. When driving is performed in a primary resonance mode (first resonance frequency), fluid can be drawn in from the first opening, and can be discharged from the second opening. When a tertiary resonance mode (tertiary resonance frequency) is used, fluid can be drawn in from the second opening, and can be discharged from the first opening. While driving can be performed at a high frequency in both the primary resonance mode and the tertiary resonance mode, in particular, when the tertiary resonance mode is used, operation can be performed at a quite high frequency that is about three times of that in the primary resonance mode. Since this allows driving at a frequency above an audible region, noise can be avoided. As for this, for example, when a soft material is used as the diaphragm, as in Patent Document 3, there is a time lag between displacement of the center portion of the diaphragm and displacement of the peripheral portion of the diaphragm. Therefore, the fluid pump in Patent Document 3 cannot be driven at a frequency higher than or equal to a frequency corresponding to the time lag. In contrast, since the piezoelectric pump of the present invention uses a metal plate having a high Young's modulus as the diaphragm, it can be driven at a high resonance frequency of the first resonance mode and the tertiary resonance mode. In particular, when driving is performed in a tertiary resonance mode beyond the human audible region, noise is not produced, and a high flow rate can be obtained. Further, since the displacement is small, stress generated in a fixed portion between the pump body and the diaphragm is reduced, and reliability is thereby improved. It is preferable that the Young's modulus of the diaphragm be 100 GPa or more. When the Young's modulus is 100 Gpa or more, a high follow-up ability is obtained when driving is performed in any of the primary resonance mode and the tertiary resonance mode. Moreover, since the loss during driving is small, the amount of generated heat is small, and the power efficiency is high.
  • The piezoelectric pump of the present invention is suited to transport compressible fluid such as air. When a piezoelectric pump discharges imcompressible fluid such as liquid, in general, check valves formed of a soft material, such as rubber or resin, are respectively provided at the inlet and the outlet, and a piezoelectric element is driven at a low frequency of about several tens of hertz. When such a piezoelectric pump is used as a pump for discharging compressible fluid such as air, the displacement amount of the piezoelectric element is quite small, and little fluid can be discharged. When the piezoelectric element is driven near the resonance frequency (primary resonance frequency or tertiary resonance frequency) of the displacement member defined by the diaphragm and the piezoelectric element, the maximum displacement can be obtained. However, since the resonance frequency is a high frequency of the order of kilohertz, the check valves cannot perform a follow-up operation. Since a check valve is not provided in the present invention, even when the piezoelectric element is driven at the frequency near the resonance frequency, imcompressible fluid can be efficiently transported without being restricted by the check valve. Further, there is no fear that operation failure will be caused by adhesion of dust or the like to the check valve, and a highly reliable piezoelectric pump can be provided.
  • It is preferable that the second opening be provided at a position where the diaphragm is maximally displaced in a tertiary resonance mode or outside the position. While the position where the diaphragm is maximally displaced in the tertiary resonance mode differs in accordance with the area ratio of the piezoelectric element and the diaphragm or the Young's modulus of the diaphragm, when the second opening (inlet) is provided at the position of maximum displacement or outside the position, a sufficient sealing ability of the second opening (inlet) can be obtained when discharging the fluid from the first opening (discharging port) in an operation cycle of the piezoelectric pump, and backflow of the fluid to be discharged can be prevented. This increases not only the discharging pressure, but also the discharging flow rate.
  • A plurality of the second openings may be provided on the same circumference centered on the first opening. When driving is performed in a tertiary resonance mode, the second opening serves as an inlet. If one second opening is provided, fluid does sometimes not rapidly flow into an annular pocket space formed between the pump body and the peripheral portion of the diaphragm, and a sufficient amount of fluid is not discharged. In contrast, when a plurality of second openings are provided on the same circumference, the fluid can rapidly flow into the annular pocket space, and the amount of discharged fluid can be increased.
  • According to the present invention, the piezoelectric element having a size such as to cover the first opening and such as not to reach the second opening is bonded to the center portion of the metal diaphragm, and the piezoelectric element is driven by a voltage having a predetermined frequency so that the portion of the diaphragm opposing the first opening and the portion of the diaphragm opposing the second opening are bent in opposite directions. Therefore, it is possible to increase the discharging pressure, and to reliably discharge the fluid even under the condition where the pressure on the discharging side is high. Moreover, the piezoelectric element can be formed only by the pump body and the diaphragm having the piezoelectric element bonded thereto, and an auxiliary component, such as a check valve, is unnecessary. This makes it possible to realize a small, thin, and highly reliable piezoelectric pump having a very simple structure.
  • BRIEF DESCRIPTION OF THE DRAWINGS
  • FIG. 1 is a general perspective view of a piezoelectric pump according to a first embodiment of the present invention.
  • FIG. 2 is an exploded perspective view of the piezoelectric pump shown in FIG. 1.
  • FIG. 3 includes cross-sectional views of the piezoelectric pump shown taken along line A-A in FIG. 1, showing a pumping operation in a tertiary resonance mode.
  • FIG. 4 includes cross-sectional views of the piezoelectric pump taken along line A-A in FIG. 1, showing a pumping operation in a primary resonance mode.
  • FIG. 5 includes cross-sectional views showing a pumping operation of a piezoelectric pump according to a second embodiment of the present invention.
  • FIG. 6 includes cross-sectional views showing a pumping operation of a piezoelectric pump according to a third embodiment of the present invention.
  • FIG. 7 is a perspective view of a piezoelectric pump according to a fourth embodiment of the present invention.
  • REFERENCE NUMERALS
      • 10: pump body (top plate)
      • 11: first opening
      • 12: second opening
      • 16: second opening
      • 20: diaphragm
      • 22: circular region
      • 23: piezoelectric element
      • 25: second opening
      • 30: presser plate
    DETAILED DESCRIPTION OF THE INVENTION
  • Preferred modes of the present invention will be described below with reference to various embodiments.
  • First Embodiment
  • FIGS. 1 to 3 show a piezoelectric pump according to a first embodiment. FIG. 1 is a general perspective view of a piezoelectric pump according to the present invention, FIG. 2 is an exploded perspective view of the piezoelectric pump shown in FIG. 1, and FIG. 3 is a cross-sectional view, taken along line A-A in FIG. 1.
  • In this embodiment, a piezoelectric pump P has a structure in which a top plate 10 that forms a pump body, a diaphragm 20, and an annular presser plate 30 are stacked in order, and these stacked components are bonded together. The top plate 10 is shaped like a flat plate having rigidity. A first opening 11 is provided at the center of the top plate 10, and a plurality of second openings 12 are provided on the same circumference centered on the first opening 11. While eight second openings 12 are provided so as to ensure the flow rate herein, the number of second openings 12 can be arbitrarily set in accordance with the required flow rate.
  • The diaphragm 20 is formed by a thin metal plate having spring elasticity. As shown in FIG. 2, the diaphragm 20 has a plurality of arc-shaped slits 21. An adhesive is applied on front and back surfaces of a region outside the slits 21, and the outside region of the diaphragm 20 is bonded and fixed by the top plate 10 and the presser plate 30. Since the region in which the adhesive is applied is separated by the slits 21, the adhesive will not spread to a circular region 22 inside the slits 21. An inner peripheral edge 31 of the presser plate 30 has a diameter slightly smaller than the diameter of the circular region 22 of the diaphragm 20, and the circular region 22 surrounded by the inner peripheral edge 31 is bendable.
  • The diaphragm 20 is placed in contact with a lower surface of the top plate 10. A circular piezoelectric element 23 is bonded onto a back surface (lower surface) of the diaphragm 20 and at the center of the circular region 22. The center of the circular region 22 of the diaphragm 20 (center of the piezoelectric element 23) is coaxial with the center of the first opening 11 of the top plate 10. Since the radius of the piezoelectric element 23 is smaller than the distance L between the first opening 11 and the second openings 12, the second openings 12 are outside the piezoelectric element 23. It is preferable that the second openings 12 be provided at the same position as a maximum displacement position where the diaphragm 20 is maximally displaced in a tertiary resonance mode or a position slightly shifted outward from the maximum displacement position.
  • The thickness of the presser plate 30 is larger than the sum of the thickness of the piezoelectric element 23, which will be described below, and the displacement amount of the diaphragm 20. This prevents the piezoelectric element 23 from touching a substrate or the like when the piezoelectric pump P is mounted on the substrate. A cut groove 32 is provided in a portion of the presser plate 30. This groove prevents an enclosed space from being formed on the lower side of the diaphragm 20 when the piezoelectric pump P is mounted on a substrate or the like, and allows a wire to be led out to the piezoelectric element therefrom.
  • In this embodiment, a piezoelectric ceramic single plate having electrodes on its front and back surfaces is used as the piezoelectric element 23, and is bonded to the back surface of the diaphragm 20 (surface opposite the top plate 10) so as to define a unimorph vibrating plate serving as a displacement member. Since the piezoelectric element 23 is expanded and contracted in a planar direction by the application of an alternating voltage (sinusoidal wave or rectangular wave), the diaphragm 20 including the piezoelectric element 23 entirely bends in the thickness direction. When driving is performed in a tertiary resonance mode (about 15 kHz) of the displacement member defined by the diaphragm and the piezoelectric element, the diaphragm 20 bends so as to be maximally displaced at a peripheral portion substantially corresponding to the second openings 12. When driving is performed in a primary resonance mode (about 5 kHz) of the displacement member defined by the diaphragm and the piezoelectric element, the diaphragm 20 bends so as to be maximally displaced at the center portion. It is preferable that the voltage applied to the piezoelectric element 23 be about ±60 V (120 Vpp) to ±120 V (240 Vpp).
  • FIGS. 3( a) to 3(e) show a pumping operation in the tertiary resonance mode of the piezoelectric pump P, that is, an operation performed when a voltage close to a tertiary resonance frequency is applied to the piezoelectric element 23. FIG. 3( a) shows an initial state, in which the entire surface of the diaphragm 20 is in contact with the pump body 10 and the first opening 11 and the second openings 12 are closed. FIG. 3( b) shows the first quarter period of the voltage applied to the piezoelectric element 23. Since the diaphragm 20 convexly bends upward, a center portion of the diaphragm 20 is pressed against the pump body 10, and a peripheral portion of the diaphragm 20 separates from the pump body 10. For this reason, the first opening 11 remains closed. However, since an annular pocket space is formed between the peripheral portion of the diaphragm 20 and the pump body 10, fluid is drawn into the pocket space from the second openings 12. In the next quarter period, the mass of a region of the diaphragm 20 on which the piezoelectric element 23 is bonded is larger than that of a region on which the piezoelectric element 23 is not bonded, because of the presence of the piezoelectric element 23, and a greater inertia effect is provided. Therefore, as shown in FIG. 3( c), the diaphragm 20 returns to a flat state on a side closer to the diaphragm (lower side) than the initial state, corresponding to the position of center of gravity of the piezoelectric element 23. In this case, since a continuous pocket space is formed between the diaphragm 20 and the pump body 10, the fluid is transferred toward the center in the pocket space formed between the diaphragm 20 and the pump body 10. In this case, both the first opening 11 and the second openings 12 are open slightly. In the next quarter period, as shown in FIG. 3( d), the diaphragm 20 convexly bends downward. Therefore, the peripheral portion of the diaphragm 20 is pressed against the pump body 10, and the second openings 12 are closed. For this reason, the fluid between the diaphragm 20 and the pump body 10 is collected to the center, and is pushed out from the first opening 11. In the next quarter period, as shown in FIG. 3( e), the piezoelectric element 23 attempts to return to a flat state. However, a pocket space thinner than the pocket space shown in FIG. 3( c) is formed, because of the position of center of gravity of the piezoelectric element 23. The outflow of the fluid continues until the diaphragm 20 is brought into contact with the first opening 11 again, as show in FIG. 3( b). Then, the operation of the diaphragm 20 returns to the operation shown in FIG. 3( b), and the operations shown in FIGS. 3( b) to 3(e) are repeated periodically. When the piezoelectric element 23 is thus driven in the tertiary resonance mode, the fluid can be drawn in from the second openings 12 and can be discharged from the first opening 11 provided at the center.
  • FIGS. 4( a) to 4(d) show a pumping operation in a primary resonance mode of the piezoelectric pump P. FIG. 4( a) shows an initial state, and FIG. 4( b) shows the first quarter period of the voltage applied to the piezoelectric element 23. Since the diaphragm 20 convexly bends downward, a pocket space is formed between the center portion of the diaphragm 20 and the pump body 10, and fluid is drawn into the pocket space from the first openings 11. In the next quarter period, the mass of the region of the diaphragm 20 on which the piezoelectric element 23 is bonded is larger than that of the region on which the piezoelectric element 23 is not bonded, because of the presence of the piezoelectric element 23, and a greater inertia effect is provided. Therefore, as shown in FIG. 4( c), the diaphragm 20 returns to a flat state on a side slightly closer to the diaphragm than the initial state, corresponding to the position of center of gravity of the piezoelectric element 23. In this case, the fluid is transferred toward the outer periphery in the pocket space formed between the diaphragm 20 and the pump body 10. In this case, both the first opening 11 and the second openings 12 are open slightly. In the next quarter period, as shown in FIG. 4( d), the diaphragm 20 convexly bends upward. Therefore, the center portion of the diaphragm 20 is pressed against the pump body 10, and the first opening 11 is closed. For this reason, the fluid between the diaphragm 20 and the pump body 10 is collected to the peripheral portion, and is pushed out from the second openings 12. In the next quarter period, when the piezoelectric element 23 is going to return to a flat state, as shown in FIG. 4( e), downward inertia is generated in the piezoelectric element 23, and a pocket space thinner than the pocket space shown in FIG. 4( c) is formed. The outflow of the fluid continues until the diaphragm 20 is brought into contact with the second openings 12 again in the next quarter period, as show in FIG. 4( b). Then, the operation of the diaphragm 20 returns to the operation shown in FIG. 4( b), and the operations shown in FIGS. 4( b) to 4(e) are repeated periodically. When the piezoelectric element 23 is thus driven in the primary resonance mode, the fluid can be drawn in from the first opening 11 at the center and can be discharged from the second openings 12 provided on the periphery.
  • An experiment was conducted by using the piezoelectric pump P as an air supply pump for a fuel cell under the following conditions. In this experiment, driving was performed in a tertiary resonance mode.
  • Applied Voltage: rectangular wave voltage of 15.5 kHz and ±60 V to ±90 V
  • Diaphragm: SUS plate having a thickness of 0.1 mm
  • Piezoelectric Element: a PZT plate having a diameter of 12.7 mm
  • Diameter of First Opening: 1.3 mm
  • Diameter of Second Openings: 0.8 mm×8 openings
  • Distance L: 8.425 mm
  • Diameter of Displacement Region of Diaphragm: 20 mm
  • When the piezoelectric pump P was driven under the above-described conditions, a static pressure of 7.5 kPa and a no-load flow rate of 2 ml/s could be obtained. As a result, it was confirmed that a piezoelectric pump having a high discharging pressure could be obtained. Further, driving was performed at a high frequency using the tertiary resonance mode, and the auditory sensitivity was low at this frequency. Therefore, noise could be avoided.
  • Second Embodiment
  • FIG. 5 shows a pumping operation in a tertiary resonance mode according to a second embodiment of the present invention. The same components as those shown in FIG. 3 are denoted by the same reference numerals, and redundant descriptions thereof are omitted. While the second openings 12 are provided in the pump body 10 in the first embodiment, second openings 25 are provided in a diaphragm 20 in this embodiment. In this case, when driving is performed in a tertiary resonance mode, fluid can be drawn in from the second openings 25 on the back side of a piezoelectric pump and can be discharged from a first opening 11 on the front side. This structure is suitable for an air supply pump in a fuel cell or a cooling pump.
  • Third Embodiment
  • FIG. 6 shows a pumping operation in a tertiary resonance mode according to a third embodiment of the present invention. The same components as those shown in FIG. 3 are denoted by the same reference numerals, and redundant descriptions thereof are omitted. In this embodiment, a part of a pump body 10 extends outward from a diaphragm 20, and a second opening 16 shaped like a concave groove is provided on a lower side of an extending portion 15 so as to extend from an inner side of an outer peripheral portion to an outer side of the diaphragm 20. An inner edge of the second opening 16 is provided outside the outer periphery of a piezoelectric element 23 and inside a fixed outer peripheral portion of the diaphragm 20, and an outer edge thereof is open on the lower side from the extending portion 15. The second opening 16 does not always need to be shaped like a concave groove, and may be formed by a communicating hole that is open outside the piezoelectric element 23 and inside the fixed outer peripheral portion of the diaphragm 20 at an inner edge and that is open outside the fixed outer peripheral portion of the diaphragm 20 at an outer edge. This case is preferred, since a greater strength can be maintained than when the openings are provided in the diaphragm 20, as in the second embodiment, and fluid can be drawn in from the back side (lower side) of the piezoelectric pump and can be discharged from the front side (upper side) when driving is performed in a tertiary resonance mode.
  • Fourth Embodiment
  • FIG. 7 shows a fourth embodiment of the present invention. In this embodiment, second openings 12 are holes each shaped like an arc centered on a first opening 11. Since a plurality of second openings 12 are also arranged in the form of a circumference in this case, an annular pocket space formed between a peripheral portion of a diaphragm and a pump body can be quickly filled with fluid, and the flow rate can be increased.
  • While the unimorph type in which a piezoelectric element that expands and contracts in the planar direction by the application of voltage is bonded to one side of a diaphragm is shown in the first to fourth embodiments, a bimorph type in which piezoelectric elements that expand and contract in opposite directions are respectively bonded to both sides of a diaphragm, or a type in which a bimorph piezoelectric element that bends in itself is bonded to one side of the diaphragm can be used.
  • While the piezoelectric pump shown in FIG. 2 has a structure in which the top plate, the diaphragm, and the presser plate are stacked, the structure is not limited thereto. Further, the outer shape of the top plate, the diaphragm, and the presser plate do not always need to be rectangular, but may be circular.
  • While the diaphragm and the pump body are in contact with each other in the initial state in the embodiment shown in FIG. 3, a shallow concave portion may be provided in the pump body so that a narrow space (pump chamber) is formed between the diaphragm and the pump body. However, it is preferable that the first opening and the second openings be closed by the diaphragm in the initial state.
  • While the piezoelectric pump of the present invention is used as a pump for transporting compressible fluid, such as air, in the above-described embodiments, it is also applicable to imcompressible fluid such as liquid. Since the piezoelectric pump of the present invention has a high discharging pressure, for example, it can be used as a compressor pump in a cooling device.

Claims (20)

1. A piezoelectric pump comprising:
a pump body;
a diaphragm fixed at an outer peripheral portion thereof to the pump body;
a piezoelectric element bonded to a center portion of the diaphragm;
a first opening provided in a portion of the pump body opposing the center portion of the diaphragm; and
a second opening provided in one of (1) an intermediate region between the center portion and the outer peripheral portion of the diaphragm and (2) in a portion of the pump body opposing the intermediate region,
wherein the piezoelectric element is sized so as to cover the first opening and not cover the second opening, and
wherein a portion of the diaphragm opposing the first opening and a portion of the diaphragm opposing the second opening are bent in opposite directions when a voltage having a predetermined frequency to the piezoelectric element is applied so that fluid is drawn in from one of the first opening and the second opening and is discharged from the other of the first opening and the second opening.
2. The piezoelectric pump according to claim 1, wherein the diaphragm is a metal plate.
3. The piezoelectric pump according to claim 1, wherein the fluid is compressible fluid, and the fluid is drawn in from the first opening and is discharged from the second opening.
4. The piezoelectric pump according to claim 3, wherein the fluid is drawn in from the first opening and is discharged from the second opening when a voltage near a primary resonance frequency of a displacement member defined by the diaphragm and the piezoelectric element is applied to the piezoelectric element.
5. The piezoelectric pump according to claim 1, wherein the fluid is compressible fluid, and the fluid is drawn in from the second opening and is discharged from the first opening by applying a voltage near a tertiary resonance frequency of a displacement member defined by the diaphragm and the piezoelectric element to the piezoelectric element.
6. The piezoelectric pump according to claim 5, wherein the fluid is drawn in from the second opening and is discharged from the first opening when a voltage near a tertiary resonance frequency of a displacement member defined by the diaphragm and the piezoelectric element is applied to the piezoelectric element.
7. The piezoelectric pump according to claim 5, wherein the second opening is provided at a position where the diaphragm is maximally displaced.
8. The piezoelectric pump according to claim 5, wherein the second opening is provided outside of a position where the diaphragm is maximally displaced.
9. The piezoelectric pump according to claim 1, wherein a plurality of the second openings are provided on a common circumference centered on the first opening.
10. The piezoelectric pump according to claim 1, further comprising a presser plate attached to the diaphragm on a side thereof that the piezoelectric element is bonded.
11. The piezoelectric pump according to claim 1, wherein the diaphragm includes a plurality of arc-shaped slits.
12. The piezoelectric pump according to claim 1, wherein the pump body includes an extending portion that extends outward from an outer peripheral portion of the diaphragm, and the second opening is provided on the extending portion so as to extend from an inner side of the outer peripheral portion to an outer side of the diaphragm.
13. The piezoelectric pump according to claim 12, wherein an inner edge of the second opening is provided outside an outer periphery of the piezoelectric element and inside the outer peripheral portion of the diaphragm.
14. The piezoelectric pump according to claim 13, wherein, an outer edge of the second opening is open on the extending portion.
15. The piezoelectric pump according to claim 1, wherein the second opening is a hole extending through the pump body.
16. The piezoelectric pump according to claim 15, wherein the second opening is arc-shaped.
17. A piezoelectric pump comprising:
a pump body;
a diaphragm fixed at an outer peripheral portion thereof to the pump body;
a piezoelectric element bonded to a center portion of the diaphragm;
a first opening provided in a portion of the pump body opposing the center portion of the diaphragm; and
a second opening provided in a portion of the pump body opposing an intermediate region between the center portion and the outer peripheral portion of the diaphragm,
wherein the piezoelectric element is sized so as to cover the first opening and not cover the second opening.
18. The piezoelectric pump according to claim 17, wherein a plurality of the second openings are provided on a common circumference centered on the first opening.
19. A piezoelectric pump comprising:
a pump body;
a diaphragm fixed at an outer peripheral portion thereof to the pump body;
a piezoelectric element bonded to a center portion of the diaphragm;
a first opening provided in a portion of the pump body opposing the center portion of the diaphragm; and
a second opening provided in the diaphragm in an intermediate region between the center portion and the outer peripheral portion of the diaphragm,
wherein the piezoelectric element is sized so as to cover the first opening and not cover the second opening.
20. The piezoelectric pump according to claim 19, wherein a plurality of the second openings are provided on a common circumference centered on the first opening.
US12/367,084 2006-12-09 2009-02-06 Piezoelectric Pump Abandoned US20090148318A1 (en)

Priority Applications (3)

Application Number Priority Date Filing Date Title
JP2006332692 2006-12-09
JP2006-332692 2006-12-09
PCT/JP2007/073555 WO2008069264A1 (en) 2006-12-09 2007-12-06 Piezoelectric pump

Related Parent Applications (1)

Application Number Title Priority Date Filing Date
PCT/JP2007/073555 Continuation WO2008069264A1 (en) 2006-12-09 2007-12-06 Piezoelectric pump

Publications (1)

Publication Number Publication Date
US20090148318A1 true US20090148318A1 (en) 2009-06-11

Family

ID=39492142

Family Applications (1)

Application Number Title Priority Date Filing Date
US12/367,084 Abandoned US20090148318A1 (en) 2006-12-09 2009-02-06 Piezoelectric Pump

Country Status (7)

Country Link
US (1) US20090148318A1 (en)
EP (1) EP2037124A1 (en)
JP (1) JP4730437B2 (en)
KR (1) KR101033077B1 (en)
CN (1) CN101490419B (en)
CA (1) CA2654688C (en)
WO (1) WO2008069264A1 (en)

Cited By (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20090168353A1 (en) * 2007-12-28 2009-07-02 Sony Corporation Electronic apparatus
US20100074775A1 (en) * 2007-01-23 2010-03-25 Mitsuru Yamamoto Diaphragm pump
US20130266461A1 (en) * 2011-04-11 2013-10-10 Murata Manufacturing Co., Ltd. Actuator support structure and pump device
US20130280105A1 (en) * 2012-04-19 2013-10-24 Christopher Brian Locke Disc pump with perimeter valve configuration
US20130323085A1 (en) * 2011-10-11 2013-12-05 Murata Manufacturing Co., Ltd. Fluid control apparatus and method for adjusting fluid control apparatus
US8747080B2 (en) 2010-05-21 2014-06-10 Murata Manufacturing Co., Ltd. Fluid pump
US20150083756A1 (en) * 2013-09-20 2015-03-26 Gojo Industries, Inc. Dispenser pump using electrically activated material
US9028226B2 (en) 2011-09-06 2015-05-12 Murata Manufacturing Co., Ltd. Fluid control device
US9046093B2 (en) 2011-09-06 2015-06-02 Murata Manufacturing Co., Ltd. Fluid control device
US9103337B2 (en) 2011-09-06 2015-08-11 Murata Manufacturing Co., Ltd. Fluid control device
US9151284B2 (en) 2011-09-06 2015-10-06 Murata Manufacturing Co., Ltd. Fluid control device
US20160377072A1 (en) * 2015-06-25 2016-12-29 Koge Micro Tech Co., Ltd. Piezoelectric pump and operating method thereof
US10260495B2 (en) 2014-08-20 2019-04-16 Murata Manufacturing Co., Ltd. Blower with a vibrating body having a restraining plate located on a periphery of the body

Families Citing this family (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB201102100D0 (en) * 2011-02-08 2011-03-23 Benest Roger S Small compressor
FR2974598B1 (en) * 2011-04-28 2013-06-07 Commissariat Energie Atomique The micro flow meter and a process for its realization
WO2013021547A1 (en) * 2011-08-05 2013-02-14 パナソニック株式会社 Fuel cell system
CN102691694B (en) * 2012-05-23 2015-01-28 浙江师范大学 Self-driven precise stepwise hydraulic power device
WO2015178104A1 (en) * 2014-05-20 2015-11-26 株式会社村田製作所 Blower
CN103994059B (en) * 2014-06-05 2015-04-08 吉林大学 Resonance piezoelectric fan with cymbal-shaped cavity
JP6028779B2 (en) * 2014-10-03 2016-11-16 株式会社村田製作所 Fluid control device
TW201819766A (en) * 2016-11-24 2018-06-01 Microjet Technology Co Ltd Air cooling heat dissipation device

Citations (30)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4011474A (en) * 1974-10-03 1977-03-08 Pz Technology, Inc. Piezoelectric stack insulation
US4939405A (en) * 1987-12-28 1990-07-03 Misuzuerie Co. Ltd. Piezo-electric vibrator pump
US5096388A (en) * 1990-03-22 1992-03-17 The Charles Stark Draper Laboratory, Inc. Microfabricated pump
US5192197A (en) * 1991-11-27 1993-03-09 Rockwell International Corporation Piezoelectric pump
US5215446A (en) * 1990-11-22 1993-06-01 Brother Kogyo Kabushiki Kaisha Piezoelectric pump which uses a piezoelectric actuator
US5542821A (en) * 1995-06-28 1996-08-06 Basf Corporation Plate-type diaphragm pump and method of use
US5594292A (en) * 1993-11-26 1997-01-14 Ngk Insulators, Ltd. Piezoelectric device
US5759015A (en) * 1993-12-28 1998-06-02 Westonbridge International Limited Piezoelectric micropump having actuation electrodes and stopper members
US6104127A (en) * 1997-05-14 2000-08-15 Honda Giken Kogyo Kabushiki Kaisha Piezoelectric type actuator having stable resonance frequency
US6227824B1 (en) * 1995-09-15 2001-05-08 HAN-SCHICKARD-GESELLSCHAFT FüR ANGEWANDTE FORSCHUNG E.V. Fluid pump without non-return valves
US20020009374A1 (en) * 2000-05-16 2002-01-24 Kusunoki Higashino Micro pump
US6435840B1 (en) * 2000-12-21 2002-08-20 Eastman Kodak Company Electrostrictive micro-pump
US6450773B1 (en) * 2001-03-13 2002-09-17 Terabeam Corporation Piezoelectric vacuum pump and method
US6481984B1 (en) * 1999-10-27 2002-11-19 Seiko Instruments Inc. Pump and method of driving the same
US6565331B1 (en) * 1999-03-03 2003-05-20 Ngk Insulators, Ltd. Pump
US20030234376A1 (en) * 2002-06-19 2003-12-25 Honeywell International Inc. Electrostatically actuated valve
US20040032186A1 (en) * 2002-07-26 2004-02-19 Ngk Insulators, Ltd, Piezoelectric/electrostrictive film type device
US20040120836A1 (en) * 2002-12-18 2004-06-24 Xunhu Dai Passive membrane microvalves
US6755626B2 (en) * 2001-07-18 2004-06-29 Matsushita Electric Industrial Co., Ltd. Miniature pump, cooling system and portable equipment
US6767190B2 (en) * 2001-10-09 2004-07-27 Honeywell International Inc. Methods of operating an electrostatically actuated pump
US6856073B2 (en) * 2002-03-15 2005-02-15 The United States Of America As Represented By The Administrator Of The National Aeronautics And Space Administration Electro-active device using radial electric field piezo-diaphragm for control of fluid movement
US6869275B2 (en) * 2002-02-14 2005-03-22 Philip Morris Usa Inc. Piezoelectrically driven fluids pump and piezoelectric fluid valve
US6874999B2 (en) * 2002-08-15 2005-04-05 Motorola, Inc. Micropumps with passive check valves
US20050074662A1 (en) * 2003-10-07 2005-04-07 Samsung Electronics Co., Ltd. Valveless micro air delivery device
US6948918B2 (en) * 2002-09-27 2005-09-27 Novo Nordisk A/S Membrane pump with stretchable pump membrane
US20060056999A1 (en) * 2000-09-18 2006-03-16 Par Technologies Llc Piezoelectric actuator and pump using same
US20060083639A1 (en) * 2004-10-12 2006-04-20 Industrial Technology Research Institute PDMS valve-less micro pump structure and method for producing the same
US20060201327A1 (en) * 2003-04-09 2006-09-14 Janse Van Rensburg Richard W Gas flow generator
US20060245947A1 (en) * 2005-04-14 2006-11-02 Seiko Epson Corporation Pump
US20060245949A1 (en) * 2005-04-13 2006-11-02 Par Technologies, Llc Electromagnetically bonded pumps and pump subassemblies and methods of fabrication

Family Cites Families (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH02149778A (en) 1988-11-30 1990-06-08 Seiko Epson Corp Piezoelectric micropump
JPH0486388A (en) 1990-07-27 1992-03-18 Seiko Epson Corp Passage structure of piezoelectric micropump
JP3418564B2 (en) * 1999-02-03 2003-06-23 セイコーインスツルメンツ株式会社 Method of driving the micro-pump
JP4629896B2 (en) * 2001-03-30 2011-02-09 セイコーエプソン株式会社 Piezoelectric elements and an electric apparatus using the same
JP2004146547A (en) * 2002-10-24 2004-05-20 Hitachi Ltd Cooling device for electronic apparatus
JP4678135B2 (en) * 2003-06-17 2011-04-27 セイコーエプソン株式会社 pump
CN100458152C (en) 2004-03-24 2009-02-04 中国科学院光电技术研究所 Micro-mechanical reciprocating membrane pump
JP2005299597A (en) * 2004-04-15 2005-10-27 Fuji Electric Systems Co Ltd Micro pump
CN100335785C (en) 2004-11-12 2007-09-05 南京航空航天大学 Piezoelectric Pump

Patent Citations (31)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4011474A (en) * 1974-10-03 1977-03-08 Pz Technology, Inc. Piezoelectric stack insulation
US4939405A (en) * 1987-12-28 1990-07-03 Misuzuerie Co. Ltd. Piezo-electric vibrator pump
US5096388A (en) * 1990-03-22 1992-03-17 The Charles Stark Draper Laboratory, Inc. Microfabricated pump
US5215446A (en) * 1990-11-22 1993-06-01 Brother Kogyo Kabushiki Kaisha Piezoelectric pump which uses a piezoelectric actuator
US5192197A (en) * 1991-11-27 1993-03-09 Rockwell International Corporation Piezoelectric pump
US5594292A (en) * 1993-11-26 1997-01-14 Ngk Insulators, Ltd. Piezoelectric device
US5759015A (en) * 1993-12-28 1998-06-02 Westonbridge International Limited Piezoelectric micropump having actuation electrodes and stopper members
US5542821A (en) * 1995-06-28 1996-08-06 Basf Corporation Plate-type diaphragm pump and method of use
US6227824B1 (en) * 1995-09-15 2001-05-08 HAN-SCHICKARD-GESELLSCHAFT FüR ANGEWANDTE FORSCHUNG E.V. Fluid pump without non-return valves
US6104127A (en) * 1997-05-14 2000-08-15 Honda Giken Kogyo Kabushiki Kaisha Piezoelectric type actuator having stable resonance frequency
US6565331B1 (en) * 1999-03-03 2003-05-20 Ngk Insulators, Ltd. Pump
US6481984B1 (en) * 1999-10-27 2002-11-19 Seiko Instruments Inc. Pump and method of driving the same
US20020009374A1 (en) * 2000-05-16 2002-01-24 Kusunoki Higashino Micro pump
US20060056999A1 (en) * 2000-09-18 2006-03-16 Par Technologies Llc Piezoelectric actuator and pump using same
US6435840B1 (en) * 2000-12-21 2002-08-20 Eastman Kodak Company Electrostrictive micro-pump
US6450773B1 (en) * 2001-03-13 2002-09-17 Terabeam Corporation Piezoelectric vacuum pump and method
US6755626B2 (en) * 2001-07-18 2004-06-29 Matsushita Electric Industrial Co., Ltd. Miniature pump, cooling system and portable equipment
US6767190B2 (en) * 2001-10-09 2004-07-27 Honeywell International Inc. Methods of operating an electrostatically actuated pump
US6869275B2 (en) * 2002-02-14 2005-03-22 Philip Morris Usa Inc. Piezoelectrically driven fluids pump and piezoelectric fluid valve
US6856073B2 (en) * 2002-03-15 2005-02-15 The United States Of America As Represented By The Administrator Of The National Aeronautics And Space Administration Electro-active device using radial electric field piezo-diaphragm for control of fluid movement
US20030234376A1 (en) * 2002-06-19 2003-12-25 Honeywell International Inc. Electrostatically actuated valve
US20040032186A1 (en) * 2002-07-26 2004-02-19 Ngk Insulators, Ltd, Piezoelectric/electrostrictive film type device
US6874999B2 (en) * 2002-08-15 2005-04-05 Motorola, Inc. Micropumps with passive check valves
US6948918B2 (en) * 2002-09-27 2005-09-27 Novo Nordisk A/S Membrane pump with stretchable pump membrane
US20040120836A1 (en) * 2002-12-18 2004-06-24 Xunhu Dai Passive membrane microvalves
US20060201327A1 (en) * 2003-04-09 2006-09-14 Janse Van Rensburg Richard W Gas flow generator
US7550034B2 (en) * 2003-04-09 2009-06-23 The Technology Partnership Plc Gas flow generator
US20050074662A1 (en) * 2003-10-07 2005-04-07 Samsung Electronics Co., Ltd. Valveless micro air delivery device
US20060083639A1 (en) * 2004-10-12 2006-04-20 Industrial Technology Research Institute PDMS valve-less micro pump structure and method for producing the same
US20060245949A1 (en) * 2005-04-13 2006-11-02 Par Technologies, Llc Electromagnetically bonded pumps and pump subassemblies and methods of fabrication
US20060245947A1 (en) * 2005-04-14 2006-11-02 Seiko Epson Corporation Pump

Cited By (21)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20100074775A1 (en) * 2007-01-23 2010-03-25 Mitsuru Yamamoto Diaphragm pump
US8308453B2 (en) * 2007-01-23 2012-11-13 Nec Corporation Diaphragm pump
US8064204B2 (en) * 2007-12-28 2011-11-22 Sony Corporation Electronic apparatus
US20090168353A1 (en) * 2007-12-28 2009-07-02 Sony Corporation Electronic apparatus
US8747080B2 (en) 2010-05-21 2014-06-10 Murata Manufacturing Co., Ltd. Fluid pump
US9506464B2 (en) * 2011-04-11 2016-11-29 Murata Manufacturing Co., Ltd. Actuator support structure and pump device
US20130266461A1 (en) * 2011-04-11 2013-10-10 Murata Manufacturing Co., Ltd. Actuator support structure and pump device
US9103337B2 (en) 2011-09-06 2015-08-11 Murata Manufacturing Co., Ltd. Fluid control device
EP2568177B1 (en) 2011-09-06 2015-10-21 Murata Manufacturing Co., Ltd. Fluid control device
US9151284B2 (en) 2011-09-06 2015-10-06 Murata Manufacturing Co., Ltd. Fluid control device
US9028226B2 (en) 2011-09-06 2015-05-12 Murata Manufacturing Co., Ltd. Fluid control device
US9046093B2 (en) 2011-09-06 2015-06-02 Murata Manufacturing Co., Ltd. Fluid control device
EP2767715B1 (en) 2011-10-11 2018-04-04 Murata Manufacturing Co., Ltd. Fluid-control device, and method for adjusting fluid-control device
US20130323085A1 (en) * 2011-10-11 2013-12-05 Murata Manufacturing Co., Ltd. Fluid control apparatus and method for adjusting fluid control apparatus
US10006452B2 (en) * 2011-10-11 2018-06-26 Murata Manufacturing Co., Ltd. Fluid control apparatus and method for adjusting fluid control apparatus
US9334858B2 (en) * 2012-04-19 2016-05-10 Kci Licensing, Inc. Disc pump with perimeter valve configuration
US20130280105A1 (en) * 2012-04-19 2013-10-24 Christopher Brian Locke Disc pump with perimeter valve configuration
US9610600B2 (en) * 2013-09-20 2017-04-04 Gojo Industries, Inc. Dispenser pump using electrically activated material
US20150083756A1 (en) * 2013-09-20 2015-03-26 Gojo Industries, Inc. Dispenser pump using electrically activated material
US10260495B2 (en) 2014-08-20 2019-04-16 Murata Manufacturing Co., Ltd. Blower with a vibrating body having a restraining plate located on a periphery of the body
US20160377072A1 (en) * 2015-06-25 2016-12-29 Koge Micro Tech Co., Ltd. Piezoelectric pump and operating method thereof

Also Published As

Publication number Publication date
KR101033077B1 (en) 2011-05-06
JPWO2008069264A1 (en) 2010-03-25
CA2654688A1 (en) 2008-06-12
WO2008069264A1 (en) 2008-06-12
EP2037124A1 (en) 2009-03-18
KR20090057215A (en) 2009-06-04
CN101490419B (en) 2011-02-02
JP4730437B2 (en) 2011-07-20
CA2654688C (en) 2011-07-26
CN101490419A (en) 2009-07-22

Similar Documents

Publication Publication Date Title
JP4629145B2 (en) Cooling system, and portable devices
US7484940B2 (en) Piezoelectric fluid pump
CN1097676C (en) Piezoelectric micropump
US9109592B2 (en) Piezoelectric micro-blower
EP1289658B1 (en) Valve for use in microfluidic structures
US8272851B2 (en) Fluidic energy transfer devices
US20150071797A1 (en) Blower
US6991214B2 (en) Microvalve normally in a closed position
US20130236338A1 (en) Disc pump with advanced actuator
US20100096027A1 (en) Check valve and pump including check valve
WO2004084274A3 (en) Piezoelectric actuator and pump using same
JP4279662B2 (en) A small pump
JP4531563B2 (en) Peristaltic micro-pump
EP1253320A2 (en) Pump and method of manufacturing same
US20050089415A1 (en) Diaphragm air pump
US7191503B2 (en) Method of manufacturing a piezoelectric actuator
JP2006522896A (en) Gas flow generator
JPH08506874A (en) Diaphragm type positive displacement pump
US6655923B1 (en) Micromechanic pump
KR0119362B1 (en) Micro-miniaturized, electrostatically driven diaphragm micropump
US6874999B2 (en) Micropumps with passive check valves
CN101052802B (en) Liquid discharge control apparatus
KR100437132B1 (en) Check valve
EP2568177B1 (en) Fluid control device
WO2012141113A1 (en) Valve and fluid control device

Legal Events

Date Code Title Description
AS Assignment

Owner name: MURATA MANUFACTURING CO., LTD., JAPAN

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:KAMITANI, GAKU;SUNAGA, MIDORI;REEL/FRAME:022239/0267

Effective date: 20090128

STCB Information on status: application discontinuation

Free format text: ABANDONED -- FAILURE TO PAY ISSUE FEE