Statistical data on crankshaft deflections of marine diesel engine

Abstract

The results of the study of crankshafts that have received a deflection during operation are presented. The reasons for the appearance of the curvature of the longitudinal axis and the consequences to which this defect may lead are considered. According to the analysis of statistical data obtained from enterprises engaged in engine repair, an increase in defects of residual deformation of deflections was noted. The necessity of collecting and systematizing cases of curvature of the longitudinal axis above the permissible value is determined. The conditions for preparing shafts for defecation have been clarified. Attention is drawn to the need to take into account the results of previous measurements and the total operating time of the engine when laying the shaft approved for further operation. The object of the study is the crankshaft of the diesel engine 6 CHN 31.8/33, used in water transport as the main marine engine. Measurements of the radial runout of twenty shafts that received deflection were made. The dependence of the measurement error on the radius of the shaft neck is established. A histogram of the frequency distribution of deflections of the crankshaft frame necks depending on the repair size number is constructed and the dependence of the deflection frequency on the repair size number is illustrated. The maximum deflection of the crankshaft of 4.10 mm with an allowable deflection of 0.03 mm is fixed. The values of deflections of diesel shafts are analyzed, their dependence on the number of the repair size and the number of the frame neck on which the deflection occurred. The frequency and significant increase in the magnitude of the deflection arrow on the fourth frame neck were noted. The necessity of using the obtained statistical data on deflections for the scientific substantiation of the technology of correction of diesel krancshafts is determined.