Abstract: An airfoil member, especially a rotor blade for a helicopter, includes an airfoil body and a servo-actuated flap tiltably connected to the airfoil body so as to form at least a portion of the trailing edge of the airfoil member. At least one piezoelectric actuator is arranged inside the airfoil member, and connected to the servo-flap via a transmission mechanism and a connecting rod linkage so as to tiltingly deflect the servo-flap as needed. Preferably, two counter-acting piezoelectric actuators are connected to the flap via respective transmission mechanisms and connecting rod linkages. An elongation of the piezoelectric actuators in the span width direction of the airfoil member is converted or redirected into an actuating motion in the chord length direction of the airfoil member by the transmission mechanisms.

Abstract: A mechanical resonator has an electronically adjustable resonance frequency and is especially adapted to be used as a tunable vibration absorber. The mechanical resonator includes an inertial mass mounted on a free end of a spring, which is secured at its other end to the structure that is to be vibrationally damped. In order to vary the resonant frequency of the resonator, an electromechanical converter such as a piezoelectric element is connected to the spring and/or the inertial mass, and a displacement and/or acceleration sensor provides a sensor signal that is dependent on the respective displacement and/or acceleration of the spring and/or the inertial mass. An electronic control circuit generates an actuating signal based on the sensor signal. The actuating signal is applied to the electro-mechanical converter, which responsively exerts an adjusting force onto the spring and/or the inertial mass.

Abstract: A piezoelectric actuator or sensor includes a solid state body made of a monolithic piezoelectric material, a plurality of actuating electrodes formed as closed-loop electrodes entirely around the perimeter of the solid state body, and a support plate with two contact electrodes respectively having interdigitally intermeshing contact fingers arranged thereon. The intermeshing or alternating contact fingers of the two contact electrodes respectively contact alternating ones of the actuating electrodes, preferably through an adhesive layer having conducting particles dispersed therein. The energized actuating electrodes effectively form virtual piezoelectric layers in the solid state body.

Abstract: An electrostrictive or piezoelectric actuator device includes a solid state actuator element (4) that is elongated in the lengthwise direction (L) and contracted in the transverse direction (T) upon application of an electric voltage thereto. The actuator element (4) is clampingly held between a housing floor and an actuator output pin (6) in a housing (2). A protective interlayer (12) is respectively arranged between the lengthwise end faces of the actuator element (4) and the housing floor and the actuator pin respectively, to protect the actuator element against transverse stress peaks. The interlayer (12) provides a soft or elastic coupling in the transverse direction and a substantially rigid, force and stroke transmitting coupling in the lengthwise direction.

Abstract: The invention relates to an electro-hydraulic actuator, especially for an antilock brake system, which directly converts electrical input energy into hydraulic useful energy and has an especially simple and problem-free design as well as very rapid adjustability. A working chamber of the actuator according to the invention is filled with an electrostrictive fluid and provided with an electrically controlled electrode system to generate an electrical field that causes a change in pressure and/or volume in the electrostrictive fluid.