회전속도 변화에 따른 베어링 전식 메커니즘

초록

The influence of rotational speed on electrical corrosion mechanisms in rolling element bearings was inves tigated through a combination of elastohydrodynamic lubrication (EHL) theory and experimental analysis. Minimum lubricant film thickness and the lubrication parameter (λ) were calculated using the Hamrock–Dowson equation under three rotational speeds of 100, 300, and 900 rpm. The theoretical results indicated that increasing rotational speed sig nificantly increased the minimum film thickness, resulting in a transition from boundary to mixed lubrication. To verify the resulting damage characteristics, electrical corrosion experiments were conducted using a custom-built rotorkit system under identical electrical and mechanical conditions. Surface damage on the inner race and rolling elements was analyzed using confocal laser scanning microscopy. At low rotational speed (100 rpm), the relatively thin lubricant film allowed fre quent micro electrical discharges, producing numerous small pits distributed across the raceway surface. In contrast, at high rotational speed (900 rpm), the thicker lubricant film reduced direct mechanical contact and surface roughness, but increased the number of, though weaker, electrical discharges, leading to larger pits and early-stage fluting patterns. Quan titative analysis showed that surface roughness decreased with increasing speed, confirming reduced mechanical wear. These results indicate that low-speed conditions are dominated by mechanical wear combined with micro-discharges, whereas high-speed conditions are governed primarily by electrical corrosion mechanisms. The findings provide important insights for predicting bearing damage and improving durability in electric drive systems.

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