Piezoelectric extension actuator
AssigneeEADS Deutschland GmbH
InventorsMarius Bebesel, Peter Jaenker
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Abstract
A piezoelectric expansion actuator for d33 piezoelements, which allows vibrations in structures to be suppressed. An expansion actuator (1) includes a piezoelectric stack (2), which consists of d33 piezoelectric elements and is arranged between output elements (4), which are attached to the surface of the structure (7). The invention applies to a piezoelectric extension actuator, which is used to control vibrations in structures. Alternatively, in order to damp vibrations between the main gearbox of a helicopter rotor and the cellular structure of the cockpit, a power application point of the output element (18, 19, 180, 190; 35, 36) is arranged at a distance from the corresponding end plate of the piezoelectric stack (22, 220; 31, 32, 33) in the axial direction (X).
Claims12
A piezoelectric expansion actuator for reducing vibrations in a structure, said actuator comprising:
- a pair of output elements attached to a surface of said structure;
- and
- a piezoelectric stack including a plurality of d33 piezoelectric elements and first and second end plates positioned on respective first and second ends of said piezoelectric stack;
- wherein,
- surfaces of said output elements which are positioned on said structure are arranged in a longitudinal direction of said structure relative to corresponding ones of said first and second end plates of the piezoelectric stack whereby, when said piezoelectric stack introduces power into said structure, a section of power application becomes larger than a length of the piezoelectric stack in order to effect a stiffness transformation;
- mechanical precompression stress is applied on the piezoelectric stack by means of a prestress element;
- and
- the prestress element comprises at least one mechanical tension spring.
A piezoelectric expansion actuator for reducing vibrations including at least one piezoactuator arranged on a strut, wherein said strut connects a main gearbox of a helicopter rotor with a cellular structure of a cockpit, each of said piezoactuator actuators comprising a pair of output elements attached to a surface of the strut and at least one piezoelectric stack made of d33 piezoelectric elements positioned between said pair of output elements, wherein resting surfaces of said output elements are arranged on the strut at a distance in relation to respective end plates of said piezoelectric stack in the axial direction whereby when said piezoactuator introduces a control force in one section of the strut for purposes of elastic dimensional change of said section of the strut, an area of section of power application is increased when compared to an area covered by said piezoelectric stack in order to thereby reduce stiffness of the section of the strut.
Dependencies are inferred from the claim text.