Daimler Chrysler Ag

Eads Deutschland Gmbh

Airbus Defence and Space Gmbh

Eurocopter Deutschland Gmbh

Airbus Deutschland Gmbh

Mtu Aero Engines Gmbh

Deutsche Aerospace Ag

Peter Jaenker

Frank Hermle

Ulrich Sigmar Schubert

Thomas Lorkowski

Henning Strehlow

Andreas Mittelbach

Hermann Gaub

Erwin Bayer

Boris Grohmann

Marius Bebesel

Felix Nitschke

Rudolf Maier

Gerhard Steiner

Alexander Kaiser

Valentin Kloeppel

Ulf Breuer

Felix Nitschk&eacute;

A DC switching device has at least one switching unit which is arranged between two terminals. Further, the DC switching device has a control unit for controlling the at least one switching unit. The switching unit has a first and a second semiconductor switching element, which are arranged in parallel with one another, the first switching element being a high-voltage switching element and the second switching element being a low-power-loss switching element. The switching unit is controllable by the control unit in such a way that, when the switching unit is switched off, initially the second switching element is switched to be non-conductive, and subsequently the first switching unit is switched to be non-conductive, and when the switching unit is switched on, initially the first switching element is switched to be conductive and subsequently the second switching element is switched to be conductive.

DC switching device and method of control

A drive system for a helicopter includes a main drive for driving a rotor the helicopter, a flywheel mass battery including at least one flywheel, a first transmission coupling the flywheel mass battery with the main drive such that, during operation of the main drive, output can be transferred from the main drive to the flywheel mass battery, and a second, variable transmission connecting the flywheel mass battery to the rotor of the helicopter such that a predetermined output can be transferred to the rotor through adjustment of a transmission ratio of the variable transmission.

Auxiliary drive system for a helicopter

A rotor blade comprises an inner rotor blade root area, a rotor blade main area disposed adjacent to the inner rotor blade root area along a length of the rotor blade and having an aerodynamically effective rotor blade profile, the profile including a nose area and a rear edge area, and a rotor blade tip disposed adjacent to the rotor blade main area along the length of the rotor blade. The rotor blade tip is configured to be deformable relative to the rotor blade main area and is operatively connected to a first actuator device. The first actuator device is configured to initiate a vertical movement of the rotor blade tip upwards or downwards relative to the lift direction. The vertical movement starts from a neutral position relative to the rotor blade main area.

Rotor blade for a rotor airplane

A friction-welding device for the integral joining of components, having an oscillator, which generates a periodic movement of a component and a welding surface provided thereon relative to another, static component and a welding surface provided thereon, with directions of movement parallel to the welding surfaces, having a compression device which presses the welding surfaces together, and a cartridge which accommodates the moved component. The oscillator includes two or a greater, even number of piezoactuators, which are arranged in pairs on a line of application and are able to be prestressed with respect to the cartridge from opposite sides under pressure generation and are able to be moved in a synchronous, oscillating manner together therewith and the component.

Friction-welding device

A deformable aerodynamic profiled member has a front profile area and a rear profile area in the outflow area. It is bounded by shells on the pressure side and/or on the suction side, converging in a rear profile edge (). D33 piezo actuators are provided in at least some locations for deformation of the profiled member. The piezo actuators are aligned such that their length changes essentially in the direction of the planes of the shells when acted upon by electricity.

Deformable aerodynamic profile

A piezoelectric expansion actuator for d33 piezoelements, which allows vibrations in structures to be suppressed. An expansion actuator () includes a piezoelectric stack (), which consists of d33 piezoelectric elements and is arranged between output elements (), which are attached to the surface of the structure (). 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 () is arranged at a distance from the corresponding end plate of the piezoelectric stack () in the axial direction (X).

Piezoelectric extension actuator

The invention relates to a linear, hydraulic pivot drive, especially for the flap control system of aerodynamic structures. Said pivot drive comprises a housing provided with ports for introducing a hydraulic medium, a piston which is arranged inside the housing and can be axially displaced by the effect of the hydraulic medium, and an output shaft which is provided with coarse threads and interacts with the piston in order to cover the axial displacement of the piston into a rotational movement. The invention is characterized in that the output shaft is integrated into the piston, the coarse threads running in the same direction and engaging in the piston, and the cross-section of the piston has a spline profile for effectively preventing a rotational movement of the piston.

Linear, hydraulic pivot drive

A piezoelectric actuating device for controlling a flap on a rotor blade of a helicopter includes a piezo element arrangement including at least one piezoelectric stack actuator. A power transmission frame is coupled to the piezo element arrangement, the power transmission frame including an abutment and a driven element and generating a force therebetween from a change in length of the piezo element arrangement upon an excitation thereof, the force acting transversely to a direction of a centrifugal force of the rotor blade. A first holding device is provided including a pair of first flexible straps configured to fix the power transmission frame relative to the rotor blade in the direction of the centrifugal force and to allow the power transmission frame to move relative to the rotor blade transversely to the direction of the centrifugal force within a limited range. A second holding device is provided including a pair of second flexible straps configured to fix the abutment relative to the rotor blade transversely to the direction of the centrifugal force and to allow the abutment to move relative to the rotor blade in the direction of the centrifugal force within a limited range.

Piezoelectric actuating device for controlling the flaps on the rotor blade of a helicopter

Body or structural noise transmitted through a connector such as a strut, that connects a noise source, such as an engine, to an enclosure, such as a passenger cabin or cell of a helicopter, is suppressed by at least one piezoactuator which is excited to counteract any vibrations of the strut caused by body noise so that body noise vibrations are cancelled or at least substantially suppressed. The excitation of the piezoactuator is controlled in closed loop fashion in response to feedback signals from a sensor secured to the connector.

Apparatus for suppressing structure borne noises

Reversibly switchable primers

Reversibly switchable cross-linking of monomers

A piezoelectric actuator has at least two piezoelectric actuator elements connected in series with each other mechanically and electrically and form a half bridge in an amplifier bridge circuit having a further half bridge formed by two series connected electronic switches which are operated or clocked by a control circuit such as a pulse modulator circuit for periodically energizing the piezoelectric actuators in push-pull fashion. A choke ( ) is connected between the junction point (JP ) of the two piezoelectric actuators and the junction point (JP ) between the two electronic switches ( ) for assuring a loss free reverse charging of the two piezoelectric actuators functioning as electrical capacitors in the energizing bridge circuit ( ). The choke functions as an energy storage and the stored energy is used in the push-pull charging of the capacitors ( ) formed by the piezoelectric elements.

Piezoelectric actuator system

An aerodynamic component such as a helicopter rotor blade has an aerodynamic flow profile, a free end and a mounting end forming a blade root for attachment to a rotor mast. A blade section between the root and the free end has a leading edge and a trailing edge as viewed in the flow or chord direction. The blade is enclosed on its suction side and its pressure side with a respective skin. A nose flap or leading edge flap is secured to the leading edge by a bearing or hinge. The blade tilting angle is adjustable by piezo-drive elements arranged in at least one pair forming an actuator for each nose flap. The piezo-elements of a pair are arranged in the chord direction one behind the other and the pair is secured to the body of the blade by a fixed point positioned between the elements of a pair. The expansion and contraction from the piezo-element closer to the trailing edge is transmitted to the flap by a push rod. The expansion and contraction of the piezo-element closer to the leading edge is transmitted to the flap by a pronged pull-fork. The push rod and the pull-fork drive a free end of a lever secured to the flap, whereby a displacement of the push rod or of the pull fork causes the tilting adjustment of the flap by a push-pull action.

Aerodynamic component with a leading edge flap

A piezoelectric actuating drive is calibrated so that displacements or movements of its actuator output beam ( ) become independent of environmental operating conditions and of piezoelectric instabilities. For this purpose an automatic determination and correlating of energizing signal values and respective displacement positions of an actuator beam ( ) are performed on the basis of first sensing or measuring striking times (t , t ) when the actuator beam ( ) encounters at least one, preferably two limit stops which limit the beam displacement caused by piezoelectric action. The change of the electric capacitance of a piezostack ( ) that displaces the actuator output beam ( ) is measured when the beam ( ) strikes a limit stop. Instead of measuring a change in the electric capacitance of the piezostack ( ), electric charge impulses may be measured at the time (t , t ) and evaluated for the correlation between the energizing control or input signal and the corresponding output beam displacement. The correlation or calibration is performed automatically by an electronic signal processing circuit when such calibration is desired in response to an operator input or it is performed automatically in response to a control program stored in a memory of the electronic signal processing circuit.

Method for calibrating a piezoelectric actuating drive

An actuator device (,) includes a piezoelectric or electro-strictive solid state actuator element (,) that is elongated upon application of an electric voltage thereto, and a transmission mechanism (,) that amplifies the stroke displacement of the actuator element. The transmission mechanism (,) includes a plurality of rigid frame members (,), including unitary frame members (,) and divided frame members (,), and elastically flexible joints (,) that respectively interconnect the frame members. Each one of the divided frame members (,) is made up of a plurality of separate parallel link rods (,). Each flexible joint (,) is made up of a plurality of individual parallel hinge members (,) that respectively connect an end of each one of the link rods (,) to the adjacent unitary frame member (,). By this division of the flexible joints and of the divided frame members into parallel sub-components, the cross-sectional thickness of each individual hinge member is reduced, and thereby the bending stiffness and the outer fiber strain of the material of the hinge members is significantly reduced while providing the same total tensile strength and tensile stiffness. The link rods of each divided frame member effectively form a parallelogram linkage for moving and guiding the output members (,) in a parallel manner.

Growing community of inventors

Garching, Germany

Peter Jaenker