Degradation phenomenon of electrical contacts by using a micro-sliding mechanism — The comparison with input waveforms concerning of minimal sliding amplitudes under some conditions

Authors have studied the degradation phenomenon on contact resistance under the influences of an external micro-oscillation. They have developed a hammering oscillating mechanism (HOM) or a micro-sliding mechanism 1 (MSM1) which provides micro-oscillations for electrical contacts. It is shown that each mechanism is able to simulate an actual degradation phenomenon on electrical contacts. And they have also developed the third mechanism, namely another micro-sliding mechanism 2 (MSM2) which provides micro-sliding driven by a piezo-electric actuator and elastic hinges, which has more precise sliding performance, less thermal drift on sliding amplitude, and smaller sized system constituted of commercial parts. In this paper, first, they consider the theoretical analysis on output waveform and output response in the case of three types of input one as external forces which are sinusoidal, rectangular, and impulsive. Second, they obtain the experimental results of minimal sliding amplitudes fluctuating resistances on electrical contacts under some conditions which are three types of input waveform as the above, three levels of frictional force which are usual (1.6N/pin), middle (1.0N/pin), and smaller (0.3N/pin)between a male-pin and a female-part using the MSM2. Third, they compare the differences on the minimal sliding amplitudes among the above conditions by means of dispersion analysis on statistical test on the degradation phenomenon of electrical contacts. Consequently it is shown that the above uncertainty in the case of rectangular waveform and in the case of smaller frictional force (0.3N/pin) become clear. In other words, the authors obtain that the larger the frictional force is the larger the minimal sliding amplitude is, and they also obtain that the amplitudes are larger in sinusoidal input than in rectangular one and are larger in rectangular input than in impulsive one. Finally the authors discuss the dynamical transient effect on an input wave and an ou- put one which leads to the minimal sliding amplitudes if it is nearly equal to relative displacement between a male-pin and a female-part.