With increased awareness of environmental issues and regulations, developments for recent automotive engines are progressing towards engines with low fuel consumption. Due to these changes, automotive engine bearings are increasingly used in harsher environments, with higher loading. These operating conditions require bearings with both conformability and fatigue resistance.
From the above background, various aluminum alloy bearings have previously been developed, including materials with solid solution treatment to improve their properties, and alloys which can be used with or without an overlay [1, 2, 3]. These materials are known to have good conformability and fatigue resistance.
However, while conventional Al-Sn-Si alloy bearings display excellent sliding properties, due to the unceasing trend for engine downsizing, more conformability is required.
In this study, by optimizing dispersion of the soft tin phase in Al-Sn-Si alloys, a bearing material with equal fatigue resistance and further improved conformability was developed. The performance of the developed Al-Sn-Si alloy bearings was confirmed with rig tests and engine bench tests.