Evaluation of the Efficiency of Impact Mechanisms on the Example of Hydraulic Rotary Hammer Drills

Abstract The efficiency of energy transfer in impact mechanisms, often referred to as impact engines, is of key importance for users of these devices, including hydraulic rotary hammer drills. The choice of a method that allows for accurate and repeatable determination of the impact frequency and impact energy as a function of supply parameters (supply flow rate, supply pressure,) is an important issue, ultimately enabling the assessment of the efficiency of these devices. For this purpose, an analysis was carried out of the available analytical, analytical-empirical, and empirical methods, along with their associated measurement systems. In conclusion to this analysis, a proprietary method was proposed, which involved empirically determining the impact frequency fum and impact energy Eum as a function of the feed rate qzum and the feed pressure pzum. Simultaneously, for hydraulic rotary-percussive drills, the rod rotational speed nwou, the feed rate qzo, and the feed pressure pzo were empirically determined. For this method, a mobile measurement station was constructed, allowing for the performance of the tests at the drilling machines’ worksite. Appropriate tests were then conducted using this station. Based on the measurement results, the mechanical, hydraulic, and overall efficiency of the tested rotary percussion drills were determined. This allows for an assessment of the performance of the tested drills and for making informed decisions about their future use. This is important for the proper organization of the hydraulic rotary hammer drills’ operation, their servicing, repairs, and overhauls.