Sensibility Analysis of Design Parameters for Journal Bearings Optimization of Mass Balancing Systems

This work presents a sensibility analysis for the journal bearings of combustion engines mass balancing systems. Applying it, it’s possible to improve the journal bearings and avoid possible failures. This analysis consists on studying the effects of the variation of the journal bearings main parameters (radial clearance, journal bearing diameter and journal bearing length) on the journal bearings operating conditions (minimum film thickness, maximum pressure and power loss). The analysis also includes the comparison and selection of the different metallic materials that can be used in these journal bearings, as well as the selection of the lubrication system groove suitable for the journal bearings used in this kind of application. This sensibility analysis shows that: increasing the radial clearance the minimum film thickness increases, the maximum pressure remains approximately the same and the power loss decreases; increasing the journal bearing length, the minimum film thickness and power loss increase and the maximum pressure decreases; increasing the journal bearing diameter, the minimum film thickness and power loss increase and the maximum pressure decreases. At last, it’s found that the white metals (Babbitts) are considered the most advantageous and indicated materials for these journal bearings, and that the lubrication system grooves should be circumferential.