Choice of materials and justification of the parameters for the over-bit hammer

Abstract

Currently, there is a lack of efficiency of intensification of the rotational drilling process. Therefore, it is proposed to amplify it with shock loads by installing a downhole hammer (DH) into the rig’s drilling assembly, for instance, SBSh-250. In addition, the PPU changes the impact system by placing between the piston-striker and the drilling tool, an intermediate element of smaller mass and size – the striker made of a special Al-Ti alloy. At the same time, it is assumed that the drilling tool will be reinforced with tungsten carbide WC and other high-strength materials. Besides the SBSh-250 machines, shock loads can be applied to disk cones used in tunneling complexes. In this case, the oscillation generator should be placed together with the disk roller cutter into the body of the rotary actuator. The article also discusses the issue related to the choice of bearing material operating under high shock loads. The proposed constructions of rock-cutting tools are calculated in the process of experimental studies in a manner that the increased impact energy does not influence the durability of the working tool and the elements of the DH impact system (selection of high-strength material for making the striker). Having selected the necessary parameters using a test stand, the improved drilling system will allow one to increase the drilling speed (productivity) by 20–30 %, to increase the speed of tunneling with the installed vibroactive disk rolling-cutter by 25 %, and also to extend the operational life of the working tool.