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Piezoelectric pump and piezoelectric vibratorPiezoelectric pump and piezoelectric vibrator description/claimsThe Patent Description & Claims data below is from USPTO Patent Application 20080038125, Piezoelectric pump and piezoelectric vibrator. Brief Patent Description - Full Patent Description - Patent Application Claims
[0001]This application claims benefit of priority under 35 U.S.C. .sctn.119 to Japanese Patent Application No. 2006-216772 filed on Aug. 9, 2006, which is hereby incorporated by reference. BACKGROUND OF THE DISCLOSURE [0002]1. Field of the Disclosure [0003]The disclosure relates to a piezoelectric pump and a piezoelectric vibrator, using a piezoelectric vibrator. [0004]2. Description of the Related Art [0005]In a piezoelectric pump that vibrates a sheet-like piezoelectric vibrator to obtain a pumping action, a pump chamber is formed by the piezoelectric vibrator and a housing. A pair of flow passages are connected with the pump chamber. The pair of flow passages is provided with a pair of check valves which are different in the direction of flow (a check valve that allows the flow of fluid to the pump chamber, and a check valve that allows the flow of fluid from the pump chamber). When the piezoelectric vibrator is vibrated, since the volume of the pump chamber changes, and operation of opening one of the pair of check valves closes with this volume change, and closing the other check valve is repeated, the pumping action is obtained. Such a piezoelectric pump is made thin, and is used as, for example, a cooling-water circulating pump for a water-cooled notebook computer. [0006]The piezoelectric vibrator has a piezoelectric body stacked on at least one of the front and rear surfaces of a shim (thin conductive metal plate). The polarization characteristics are given in front and rear directions of the piezoelectric body. Thus, when positive and negative polarities are given in the same direction as or in a direction opposite to the polarization direction of the piezoelectric body, one surface expands and the area of the other surface reduces. For this reason, when the positive and negative polarities to be given to the front and rear surfaces of the piezoelectric body are reversed alternately, a cycle that one of the front and rear surfaces expands and the other surface shrinks is repeated, and thereby the shim will vibrate. [0007]See, for example: 1] JP-UM-B-2510590; 2] JP-UM-A-3-8679; and 3] JP-A-2004-257337. [0008]Conventionally, a piezoelectric vibrator used for such a piezoelectric pump has a flat-plate shape (disk shape), and has a fluid-tight structure in which an O ring (liquid-tight seal member) made to abut on a peripheral edge of the vibrator is compressed between the peripheral edge and the housing. The compressed O ring gives a force to between the piezoelectric vibrator and the housing in a direction in which they are separated from each other. Although this force does not affect the fluid-tight structure in a short term, it is possible to affect the fluid-tight structure over a long term. It is desirable to make a perfect fluid-tight structure for applications like the above-mentioned cooling-water circulating pump for a water-cooled notebook computer. SUMMARY [0009]The disclosed structure aims at obtaining a piezoelectric pump with a highly-reliable fluid-tight structure around a piezoelectric vibrator on the basis of awareness of the above problems. [0010]The disclosed structure also aims at obtaining a piezoelectric vibrator capable of easily obtaining a highly-reliable fluid-tight structure. [0011]The disclosed structure has been made on the basis of a perception that the reliability of a piezoelectric vibrator improves when the axial direction of the vibrator is adopted as the compression direction of the vibrator, on the basis of a recognition that a liquid-tight seal member in a conventional flat-plate-shaped (disk-shaped) piezoelectric vibrator cannot be compressed in a direction orthogonal to a planar direction of the vibrator, and this compression structure is a destabilizing factor of a fluid-tight structure over a prolonged period of time. [0012]That is, according to one aspect, there is provided a piezoelectric pump including a piezoelectric vibrator formed by stacking a piezoelectric body on at least one of the front and rear surfaces of a shim made of a thin conductive metal. A housing makes the peripheral edge of the piezoelectric vibrator liquid-tight to form a pump chamber. An alternating current is applied to between the shim of the piezoelectric vibrator, and the piezoelectric body to vibrate the piezoelectric vibrator, thereby generating a pumping action. A cylindrical bent part is formed at a peripheral edge of the shim of the piezoelectric vibrator, and a liquid-tight seal member is interposed between the cylindrical bent part and the housing. [0013]As to the pump chamber, a type in which a pump chamber is formed on one of the front and rear surfaces of the piezoelectric vibrator, and a type in which pump chambers are respectively formed on both the front and rear surfaces can be adopted. In the type in which a pump chamber is formed on one of the front and rear surfaces of the piezoelectric vibrator, it is desirable that a liquid-tight seal member is located on either an inner peripheral surface or an outer peripheral surface of the cylindrical bent part of the shim of the piezoelectric vibrator. [0014]On the other hand, in the type in which pump chambers are formed on both the front and rear surfaces of the piezoelectric vibrator, it is desirable that liquid-tight seal members are respectively located on inner and outer peripheral surfaces of the cylindrical bent part of the shim of the piezoelectric vibrator. [0015]Further, it is preferable that the shim has an outwardly bent flange part formed at an end of the cylindrical bent part thereof. [0016]According to another aspect of the invention, there is provided a piezoelectric vibrator including a piezoelectric body stacked on at least one of the front and rear surfaces of a shim made of a conductive metal thin plate, and a cylindrical bent part formed at a peripheral edge of the shim. BRIEF DESCRIPTION OF THE DRAWINGS [0017]FIG. 1 is a schematic exploded view showing one embodiment of a piezoelectric vibrator according to the disclosure; [0018]FIG. 2 is a half-section perspective view of chief parts, showing one embodiment of a piezoelectric pump using the piezoelectric vibrator of FIG. 1; [0019]FIG. 3 is a sectional view of FIG. 2; [0020]FIG. 4 is a sectional view showing another embodiment of the piezoelectric pump using the piezoelectric vibrator of FIG. 1; [0021]FIG. 5 is a schematic exploded view showing another embodiment of the disclosed piezoelectric vibrator; Continue reading about Piezoelectric pump and piezoelectric vibrator... Full patent description for Piezoelectric pump and piezoelectric vibrator Brief Patent Description - Full Patent Description - Patent Application Claims Click on the above for other options relating to this Piezoelectric pump and piezoelectric vibrator patent application. ###  How KEYWORD MONITOR works... a FREE service from FreshPatents1. Sign up (takes 30 seconds). 2. Fill in the keywords to be monitored. 3. Each week you receive an email with patent applications related to your keywords. Start now! - Receive info on patent apps like Piezoelectric pump and piezoelectric vibrator or other areas of interest. ### Previous Patent Application: Medical pump Next Patent Application: Assembly for transporting fluids Industry Class: Pumps ### FreshPatents.com Support Thank you for viewing the Piezoelectric pump and piezoelectric vibrator patent info. 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