Degradation Phenomenon of Electrical Contacts by a Micro-Sliding Mechanism -The comparison of the evaluated minimal sliding amplitudes under some conditions using the mechanism

Abstract:
Authors have developed a mechanism which gives damping vibration to electrical contacts by periodical hammering-oscillation and another mechanism which supplies reciprocal micro-sliding to electrical contacts directly driven by a magnetostrictive actuator. It is shown that each mechanism is able to make a test simulate an actual degradation phenomenon on electrical contacts by the effect of micro-oscillation. By using the mechanisms and their models the authors have studied the influences of micro-oscillation on contact resistance. In this paper, first, it is shown that there is the degradation phenomenon of electrical contacts in experimental results using another reciprocal micro-sliding mechanisms 2 (MSM2). MSM2 is a new mechanism and causes the sliding displacements by a piezo-electric actuator and four elastic hinges. And it is also shown that the phenomenon depends on contact frictional forces between male-pins and female-parts, sliding amplitudes, and input waveforms. Second, it is indicated that there are the minimal sliding amplitudes under which there is rarely degradation phenomenon and over which there is mostly degradation phenomenon in the following conditions. The conditions are two types of input waveform, three levels of frictional force, and the number of pins. The waveforms are sinusoidal and rectangular. The initial frictional forces between male-pins and female-parts are normal (1.6N/pin), middle (1.0N/pin), and smaller (0.3N/pin). And the number of pins are 10 (in a connector) and 1. Next, it is also indicated that there are the minimal sliding amplitudes, correlating to input waveform, contact frictional force, and the number of pins, which are estimated from the experimental results. After statistical process, the estimated values are changed slightly to another values. Moreover, each value of two-sided 95% confidence interval is calculated respectively. Consequently the authors consider that it is input waveform, frictional force, or experimental object (the number of pins) which affects the limit amplitude effectively and strongly. They also consider that there is the different physical process between the phenomenon by sinusoidal input and that by rectangular one. And they think that there is the different response process, which are caused by stiffness of the object or efficiency of the transferred force, between the phenomenon by a couple of pin and that by ten couples of pin in a connector.