Robert Boschgmbh

Bertram Sugg

Friedrich Boecking

Rudolf Heinz

Udo Schulz

Wolfgang Stoecklein

Volker Pitzal

Johannes-J&ouml;rg Rueger

Matthias Mrosik

Ulrich Schoor

Johannes-Jörg Rueger

A piezoelectric actuator, for example for actuating a mechanical component, has a multilayered structure of piezoelectric layers and, in a piezoelectrically active region, can be acted on with an electrical voltage by means of internal electrodes that are situated between the layers. The layer structure of the piezoelectric actuator includes inactive regions; at least the top part or bottom part, as an inactive region without internal electrodes, is comprised of a material whose dielectric constant is less than the dielectric constant of the active region.

Piezoelectric actuator

A piezoelectric actuator for actuating a mechanical component in which the piezoelectric actuator is provided with a multilayer construction of piezoelectric layers and can be acted upon by an electrical voltage in a piezoelectrically active region via inner electrodes disposed between the layers. At least one inactive region is present in the layer construction of the piezoelectric actuator, and this region is formed without inner electrodes, of a material whose mechanical and thermal properties match the properties of the active region, including the combination and the interaction of the material of the piezoelectric layers and of the inner electrodes.

Piezo actuator

A piezoelectric actuator for actuating a mechanical component, having a multilayered structure of piezoelectric layers with inner electrodes disposed between them and contacting outer electrodes on alternating sides and the piezoelectric actuator has chamfered corners or edges. In the region of the corners or edges, on the sides of the piezoelectric actuator on which the inner electrodes with alternating polarities are routed to the respective outer electrodes, the inner electrodes have a contour that makes it possible to achieve a lower field intensity between the inner electrodes of alternating polarities in the structure of piezoelectric layers. This is achieved by virtue of the fact that on the side that does not contact the outer electrodes, the edge has an obtuse angle (&#x221d;) or is rounded.

The invention describes a method and an apparatus for charging a piezoelectric element, for example, used as an actuator in a fuel injection system of an internal combustion engine. The method and apparatus are characterized in that the piezoelectric element is activated by an activation voltage having a value set as a function of manufacturing characteristics of the particular piezoelectric element and based upon, for example, a correction value for injected fuel volume.

Compensation of batch variation in the travel due to variations in the layer thickness or number of layers in multi-layer piezoelectric elements

Fuel injection system comprising a piezoelectric element for controlling the amount of injected fuel and further comprising a control unit for determination of a possible fault of the piezoelectric element or of an electric circuitry driving the piezoelectric element based upon a value related to the capacitance of the piezoelectric element.

Fuel injection system

A piezoelectric actuator is described, for example for actuating a mechanical component, in which a piezoelectric element that produces tensile or compressive force acting on an actuation element is provided. The piezoelectric element has a multi-layer structure of piezoelectric layers with internal electrodes ( ) disposed between them. The contacting of the internal electrodes ( ) on alternate sides takes place by means of external electrodes ( ). External electrical connections ( ) for the lateral contacting are affixed to an inactive end region ( ) in the multi-layer structure, which has a heat-conducting core ( ) with a favorable heat conductivity.

Piezoelectric actuator for positioning with heat dissipating inactive end section

The invention relates to a piezoelectric actuator in particular for actuating control valves or injection valves in internal combustion engines in motor vehicles, having a piezoelectric actuator body, in particular in the form of a multilayer laminate of stacked layers of piezoelectric material and intervening metal or electrically conductive layers acting as electrodes, in which one of the face ends of the actuator body is fixed on a highly heat-conducting or metal actuator base, in which the piezoelectric actuator includes at least one highly heat-conductive cooling body joined highly heat-conductingly to the side faces of the actuator body and to the actuator base.

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Gerlingen, Germany

Bertram Sugg