Oil hydraulic rock drills have been used on the field of mining and public works. This paper treats the percussion type rock drill, which is driven by the interaction of a piston and valve. Sensitivity analysis is applied to an investigation of the influence of design parameters on the performance of the oil hydraulic rock drill. It is demonstrated that the effect of leakage from the rear chamber of the piston is more sensitive to the performance. For the purpose of optimum design the influence of the construction of the oil hydraulic rock drill is also indicated choosing dimensions of the piston as variable.
