High power piezoelectric bender
AssigneeMotorola, Inc.
InventorHugo Willy Schafft
Life of this patent
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Abstract
A bimorph bender is comprised of a pair of piezoelectric circular discs having diametrically opposed surface portions. Signal carrying electrodes are formed contiguous with each surface portion. A center vane is sandwiched between the discs maintaining them in a fixed spaced relation. The bender dishes in response to the electrical signals appearing at the electrodes. Mechanical coupling to the bender is provided by a washer which is affixed in the central portion of the bender. The washer is made of a high specific stiffness material for maintaining a high electro-mechanical coupling factor. The resulting structure provides a highly reliable and efficient power transducer.
Claims11
A bimorph bender for driving a mechanical member comprising:
- a pair of disc members, each disc member formed of a piezoelectric material and having first and second diametrically opposed surface portions, each disc further provided with a centrally located coupling hole defined by a disc coupling hole surface;
- electrode members contiguous with a substantial portion of each disc member first and second surface portions;
- a center vane member, provided with a centrally located coupling hole, for separating the discs in fixed spaced relationship and aligning the coupling holes to form a coupling cavity;
- a coupling member comprised of an electrically insulating and mechanically stiff material, having a stiffness approximately equal to or greater than said piezoelectric material, and having a predetermined surface dimension for insertion in the coupling cavity, the coupler member further provided with a means adapted to rigidly affix the coupling member to the mechanical member;
- and
- a means for affixing the coupling member within the coupling cavity such that the coupling member is stiffly attached to the coupling hole surface of each disc,
- whereby the coupling member material and dimension maintains a high mechanical stress force across the bender surface to achieve a high electromechanical coupling factor thereof while providing a means adapted to mechanically affix and transmit movement of the bender to the mechanical member.
In a bender having a pair of circular discs made of a piezoelectric material, each disc having diametrically opposed faces with electrodes thereon, the discs being separated by a center vane member, in fixed spaced relationship to form a predetermined bender thickness, the improvement for driving a mechanical member comprising:
- a predeterminedly dimensioned aperture provided through the bender, the aperture being located central to the bender and on axis with a line perpendicular to the face of each disc,
- a cylindrical coupling member made of an electrically insulating meberial having stiffness approximately as great as, or greater than said piezoelectric material, the coupling member having a predetermined diameter for insertion within the aperture and having a vertical dimension substantially equal to the thickness of the bender, the coupling member including means adapted to rigidly affix the coupling member to the mechanical member;
- a means for rigidly affixing the coupling member vertical outer surface to the discs,
- whereby the coupling member material and dimension maintains a high mechanical stress force across the bender surface to achieve a high electromechanical coupling factor thereof while providing a means adapted to mechanically affix, and transmit movement of, the bender to the mechanical member.
Dependencies are inferred from the claim text.