ИССЛЕДОВАНИЕ ПРОЦЕССА ИЗНАШИВАНИЯ ШЕЕК КОЛЕНЧАТОГО ВАЛА, ВОССТАНОВЛЕННЫХ УСТАНОВКОЙ СТАЛЬНЫХ ПОЛУКОЛЬЦЕВЫХ НАКЛАДОК

Abstract

Installation of steel semi-ring linings on the crankshaft journals is a rational technological solution that can significantly reduce the thermal deformation of the crankshaft in the process of its restoration compared to building-up welding or tape welding. (Research purpose) The research purpose is studying the wear rate in crankshaft journals restored by installing steel semi-ring linings. (Materials and methods) The wear rate in the restored crankshaft journals has been theoretically calculated using I.V. Kragelsky’s method. The diesel engine crankshaft in a Volkswagen Transporter car, which was in operation, has been taken as an experimental sample. The semi-ring linings have been installed on the crankshaft journals by butt welding to each other. The main criterion for the experimental evaluation is the wear rate of the restored journals under real operating conditions. When measuring wear, both the profilogram method and the micrometric method have been used for measuring the diameters of the crankshaft journals before and after a certain car run. (Results and discussion) The values of the main journal wear during real car run are comparable to the theoretical calculation results. The wear degree of the connecting rod journals exceeds the wear of the main ones, which can be explained by absence of heat treatment of the half rings in the connecting rod journals when restoring the shaft. The actual values of ellipsity as well as taper rates of the journals are within the acceptable values. The wear values obtained by measuring roughness before and after the test period are comparable to those obtained by micrometric measurement. (Conclusions) The wear rate of both connecting rod and main crankshaft journals is comparable to the values determined by theoretical calculation, which makes it possible to conclude that the experimental research has a positive result. The wear rates determined both experimentally and theoretically are within the limits established by earlier studies in the field of tribology, which indicates the reliability of the experimental results. Thus, the applicability of the method of installing steel semi-ring linings when restoring crankshafts of automotive engines has been confirmed.