Robert Boschgmbh

Alexander Hedrich

Rudolf Heinz

Friedrich Boecking

A piezoelectric actuator in which a piezoelectric element is present for subjecting an actuating element to a tensile or compressive stress. A sleeve is secured to a foot part, to which the piezoelectric element is secured and by way of which the piezoelectric element is kept centered in a housing under mechanical prestressing, and this sleeve surrounds the piezoelectric element in such a way as to stabilize it mechanically, at least in partial regions that are electrically insulated from the piezoelectric element. Between the sleeve and the piezoelectric element, a heat-conducting elastomer is placed, and the sleeve comprises a heat-conducting material that is deformable within predetermined limits.

Piezo actuator

A piezoelectric actuator, for example for actuating a mechanical component, is proposed, which has a multilayered structure of piezoelectric layers and internal electrodes ( ) disposed between them. As a conductive surface, a first external electrode ( ) is affixed to a respective side surface and is contacted by the respective internal electrodes ( ), and a second net-like or woven cloth-like external electrode ( ) is disposed on the first external electrode ( ). In the regions of the piezoelectric layers, which have respective internal electrodes ( ) that are respectively contacted on opposite sides from one another, there is a passive zone ( ) without an internal electrode layer. The ceramic piezoelectric material&mdash;at least in the passive zone ( )&mdash;and the material of the second external electrode ( ) have almost the same thermal expansion coefficient, by means of which the influence of mechanical stresses in the piezoelectric actuator can be reduced.

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Stuttgart, Germany

Alexander Hedrich