Abstract

In the present study it is shown how to change the main indicators of vibrations of crankshaft, in case of changing its masses. In the study it was taken the crankshaft of diesel engine with 4 cylinders in line with five main journals. To study the torsional vibration of the crankshaft system, the first it is carried the construction of equivalent reduced scheme with five discs connected to four flexible shafts.  Results show that the reduced inertia moments of disks for the case with counterbalances grow to 24%. Free frequency and vibration forms, is calculated by using Holxer-Tole method. Results show that the increase of counterbalance mass leads in the reduction of vibration frequency. For the crankshaft with counterbalance the vibration form does not change, but the forced vibration amplitudes increase over 11%. Most charge part in torsion, remains the fifth shaft equally as the crankshaft without counterbalance.