電気接点における接触抵抗は、接点の信頼性を左右する重要な要素である。そのため、接触抵抗の接触荷重に対する挙動を知ることは、重要な課題となっている。本研究では、銅合金上の錫および銀めっきを施したサンプルを用い、接触抵抗の荷重依存性に対する接点形状、めっき種、めっき厚みの影響を調査した。コネクタの接点を模擬した半球状のサンプルと平板との接触における接触抵抗および接触面積の測定を各荷重ごとに行い、これらの実験結果を、接触荷重と接触面積との関係、及び、接触面横と接触抵抗の関係に分離し、解析を行った。荷重と面積の関係については、有限要素法を用いた接触解析、また、接触面積と抵抗の関係については、めっきの影響を加味した集中抵抗の理論式を用いた解析を行った。その結果、酸化被膜のない銀めっきについては、理論予測と実測値が一致し、酸化被膜のある錫めっきについては、実用範囲である高荷重域において理論予測値と実測値が一致した。以上により、接触荷重と接触抵抗の関係を計算にて予測することが可能となった。%Electrical contacts are an important part of electrical circuits and many reliability problems are related to electrical contacts' failure. It is important to investigate relationship between load and contact resistance which made contact reliability. In this study, the effect of contact shape, plating material and plating thickness on contact resistance was examined. The samples were constructed of a copper alloy with tin or silver plating. The resistance of the embossment shape and plane contact was measured by using a four-probe method at each contact load. And indentation contact area is measured by optical microscope. The experimental results of the relation between contact area and contact resistance were separated two parts as the load-contact area relation and the contact area-resistance relation. The load-contact area relation is predicted by FEM contact analysis and the contact area-resistance relation is analyzed by the theory of constriction resistance with plated layer. As results, the experimental results of silver plating sample which has no oxide film were good agreement with the theoretical results and the experimental results of tin plating sample which has oxide film were agreement with the theoretical results at higher load which is practical use of terminal connector. Therefore it is able to predict the load-contact resistance curve.
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