Elektric rotary-percussion drilling machine of high power – feasibility study

Abstract

Rotary-percussion drilling machines are commonly used for drilling hard-to-cut and abrasive rocks. Currently, in underground mining, drilling jumbos with hydraulic drilling machines and rotary percussion drilling machines are used in chamber-and-pillar systems. The article presents results of the work aimed at assessing the technical possibilities of creating an electric rotary-percussion drilling machine with the parameters of currently used hydraulic drills. The biggest challenge is to obtain high impact energy and frequency as well as rotation speed and torque while limiting the weight and size of the drilling machine. The required parameters of the electric drilling machine were the parameters ​​of the hydraulic drilling machines used at KGHM Polska Miedź S.A. Known and applicable design solutions for electric drilling machines were analysed including the reported inventions in Poland and abroad. Then, three design solutions were selected and dynamic model tests were carried out, the main goal of which was to estimate the required torque, which, combined with the rotation speed, determines the power of the electric motor. As a result, the solution was obtained, which in terms of weight and dimensions does not differ significantly from the hydraulic drilling machines, while at the same time enabling the achievement of similar operational parameters that determine the mechanical drilling speed.