PHOTOMECHANICAL IVESTIGATION OF STRESSES ON THE CONTOUR OF CRANKPIN OIL HOLE IN A CRANKSHAFT OF INTERNAL COMBUSTION ENGINE

Crankshafts fail from fatigue in locations of the greatest stress concentration. Such areas are the openings of lubricant holes on crankpin and main journals of the shaft and the fillets between webs and journals. Factors of safety in these locations are minimal. When analyzing crankshafts, the main journals are analyzed for torsion only and the crankpins - for both bending and torsion. The influence of fillet size on bending stress distribution in the plane of the cranks was investigated in the first stage of studies [2; 3] and the distribution of torsional stresses of the crankpin was further studied in [4-6]. This paper presents an original methodology for determining the intensity of stresses in oil hole openings caused by torsion and bending loads on crankshaft journals that arise in the working cycle of internal combustion engine by physical modeling with optical transparent flat models according to the method of photomechanics. The necessary rigging equipment for the experiments of bending and torsional loading of crankshaft models was designed and manufactured. The performed analysis made it possible to establish the qualitative and quantitative factors that affect the stresses on the contour of oil hole opening from bending and torsion induced deformations of the crankpin