Patent attributes
In manufacturing electromechanical drive elements, vibration properties are defined in a test environment. These properties are found to give a good operation when being arranged in a motor. Two flexural vibration modes are defined. One is an s-mode connected to an element being strapped at two supports at respective outer portions. The s-mode have three nodal points. The other vibration mode is an ε-mode connected to an element being strapped at the supports and at a drive pad arranged at a middle portion. The ε-mode has one nodal point at each side of the middle portion and the middle portion has a stroke amplitude that is smaller than stroke amplitudes at portions between the middle portion and the nodal points. An average of the resonance frequencies of the s-mode strapped at two and three points, respectively, differs from and the ε-mode resonance frequency by less than 25%.