| Abstract: | An analysis is presented of the working process in cyclic-action shaping of horizontal boreholes in soil. Advance of the tool in the required direction is effected through asymmetric vibrational displacements induced by a pneumatic mechanism. The machine is incapable of utilizing the unloading energy of the soil as part of the input. The analysis is based on approximative characterization of resistance force of the soil and the air pressure in the pneumatic mechanism. As regards the influence of external friction on the process, it was established that increase of the former up to a certain level results in considerable saving in the energy requirement, combined with a significant increase in output. The expressions obtained in this context yield the conditions under which the energy requirement is minimized. |
