A Study of Lead-Free Aluminum Alloy Bearings with Overlay for Recent Automotive Engines

Recently, a Lead-free aluminum alloy bearing with available fatigue strength is partially applied for plain bearings in automotive engines as replacement of a conventional copper alloy bearing with lead based overlay, according to requirement of ELV regulation, which requires the lead removal from bearing. However, our recent investigation made clear that the aluminum alloy bearing did not have enough running-in property when operated under severe condition of thinner oil film in recent automotive engine with further higher performance. Based upon these backgrounds, a lead-free bearing was newly developed by applying overlay onto the aluminum alloy bearing for better running-in property of the bearing.