Herrmann Ultraschalltechnik Gmbh & Co. Kg

Jorg Wallaschek

Jens Twiefel

Gabriel Ertz

Ulrich Vogler

The present invention relates to a method for determining at least one physical characteristic value of an electromechanical oscillatory system, which comprises a piezoelectric element and at least one additional element coupled, with respect to oscillation, to the piezoelectric element, the piezoelectric element having an electrode and a counter electrode. The method comprises the following steps: (a) applying an electrical alternating voltage between the electrode and the counter electrode for the duration of an excitation interval in order to induce mechanical oscillation of the oscillatory system or of a sub-system of the oscillatory system, so that after the excitation interval has expired, the oscillatory system or the sub-system performs a free oscillation without excitation, (b) after the end of the excitation and during the free oscillation of the oscillatory system or of the sub-system without excitation: (i) measuring a time curve of a voltage U between the electrode and the counter electrode, or (ii) short-circuiting the electrode and the counter electrode with a line and measuring a time curve of a current I through the line, and (c) determining the at least one physical characteristic value of the electromechanical oscillatory system from the time curve of the voltage U, which time curve was measured in step b) i), or the time curve of the current I, which time curve was measured in step b) ii).

Method and generator for characterizing an oscillatory system

An ultrasonic vibration device has a sonotrode and a converter, the converter having a piezoelectric actuator for converting an electrical alternating voltage into a mechanical vibration. A first piezoelectric sensor element outputs a first measurement signal which varies in dependence on the vibration amplitude of the mechanical vibration. To permit measurement of at least one intensive state variable like the temperature, or the aging state of the piezoelectric actuator, a second piezoelectric sensor element outputs a second measurement signal which also varies in dependence on the vibration amplitude of the mechanical vibration. However, the second piezoelectric sensor element differs in a physical property from the first.

Ultrasonic vibration device having a first and a second piezo sensor

The present invention concerns an ultrasonic vibration unit having a converter () for converting an electric ac voltage into a mechanical ultrasonic vibration and a sonotrode which is vibrationally coupled to the converter (), wherein the sonotrode and the converter () are matched to each other in such a way that the ultrasonic vibration unit can vibrate with a natural frequency f, in which a standing longitudinal wave having at least one vibration node and at least two vibration antinodes is formed within the ultrasonic vibration unit. To provide an ultrasonic vibration unit in which the parasitic vibrations which usually occur in operation with a working frequency are slight or do not occur, wherein at the same time the actual working frequency is not attenuated, it is proposed according to the invention that there is provided a damp vibration absorber unit () connected to the ultrasonic vibration unit by way of a coupling element (), wherein the coupling element () is connected to the ultrasonic vibration unit at a vibration node, wherein the vibration absorber unit () is connected to a damping element () which is so adapted that it damps a vibration of the vibration absorber unit ().

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Hannover, Germany

Jorg Wallaschek