| Research Abstract |
Mechanical oscillators are superior in frequency and amplitude stabilities to other mechanical and electrical devices. So far the oscillators have been used mainly for timers because complicated structures could not be manufactured. Recently, however, by the progress of micromachining technology, new applications such as probes for SPM, laser scanners and motors are emerging. In these devices, performance is decided by the frequency and amplitude stabilities which are decided by the kinetic energy dissipation from the oscillators. In this research, theoretical and experimental methods to evaluate energy loss are developed, and new applications of oscillators are presented. Major results are as follows :
1. A simple formulas for evaluating airflow damping, the largest loss factor of the kinetic energy, is derived by using the approximate solution of the Navier-Stokes equation.
2. A precise and simple apparatus for measuring structural damping coefficient of internal friction, the second largest loss factor, is developed. Its measurement accuracy is higher than 10^<-6>.
3. As an application of the micro-oscillators, an amplitude control method to measure the wet surface by AFM was developed. When the kinetic energy of the oscillator is larger or smaller than the adsorption energy by the surface tension, solid or liquid surface is measured respectively.
4. As the second application, a design method of the vibrational friction drive motor used for wristwatches was clarified. The effect of the collision loss, friction coefficient, exciting frequency, amplitude and the mode shape to the rotation efficiency was examined theoretically and experimentally.
5. As applications of normal-sized oscillators, generators which use mechanical vibration as input energy, and a diagnosis system that detects tool wear from cutter vibration were developed.
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