Impact performance optimization for hydraulic rock drill based on stroke and flow compensation factors

In response to the issues of overheating of the shell and insufficient impact energy of the hydraulic rock drill, this paper focuses on the hydraulic rock drill with alternating front and rear return chambers. By establishing nonlinear and linear dynamic models, the influence of stroke amount and flow compensation on the hydraulic system is investigated, and an optimization method for impact characteristics is proposed. Considering factors such as hydraulic clamping force, fluid leakage, and rock properties, a feedback control numerical model is established for the impact system. This model is based on principles drawn from wave dynamics and fluid dynamics theories. It elucidates the dynamic characteristics of the impact piston, reversing valve, and high-pressure accumulator. Combining three linear models, this study investigates the influence of the advance amount of the return signal chamber and the gas pre-charge pressure of the high-pressure accumulator on the impact characteristics. A thorough laser experiment has been created to evaluate the actual rock drilling capabilities of the impact system. Proposed optimal parameters are tested experimentally to compare the impact performance before and after the enhancement. The results indicate an increase in impact power, validating the effectiveness of the proposed improvement method.