康明斯曲轴和轴承分析法.pdfVIP

Cummins Crankshaft and Bearing Analysis Process Ilya Piraner, Christine Pflueger, Oliver Bouthier Cummins, Inc. 1. INTRODUCTION This paper outlines the steps taken for the preliminary crankshaft and bearing design analysis at Cummins. Major crankshaft dimensions must be chosen early in the engine design process because they affect overall engine dimensions. Proper selection of the crank dimensions requires multiple design iterations to avoid design alterations during the development stage when any change is very costly. Therefore, the crankshaft and bearing analysis should be not only quick, but also accurate and robust because some of the parameters may not yet be well defined at this preliminary stage. A number of considerations need to be addressed in the preliminary crankshaft and bearing design analysis. Among these considerations are crank stress, bearing performance, integrity of the crankshaft joints, and the impact of the crank on the block stress and deformation. Though each consideration may require a detailed and complicated analysis, simplified approaches have been developed over the years by the industry and successfully applied at Cummins. This paper describes a two-stage process adopted by Cummins for crankshaft analysis. The first stage is a simplified analysis, which combines a “quasi-static” crankshaft model and a rigid hydrodynamic bearing model to address crankshaft fillet bending stress and bearing performance characteristics. The torsional vibration effects are accounted for independently based on a simple one-dimensional dynamic mass-elastic model.