Sliding Surface Profiling for Fatigue Prevention in Big End Con-Rod Bearings

Pressure “peaks” in crank end bearings can be flattened in the axial direction by hourglass surface profiling in highly wear resistant bearings. In more wear prone bearings, this same effect can be achieved by the introduction of circumferential microgrooves. A computer program (LOCUS) was written that calculates the maximum pressure, oil flow rate and minimum film thickness (among other variables) for bearings under dynamic loading. An actual bearing was simulated with and without pr£ filing. A 26% reduction in peak pressure was achieved as well as a 11% increase in oil flow rate. However, the minimum oil film thickness decreased by 61% indicating that this concept can only be applied to these bearings that do not have critical film thickness limitations.