Rationale for choosing elastic element for adaptive cutting bit

Abstract

Introduction. Problems of the adaptive drilling are currently discussed in a number of works. They are largely devoted to the regulation of standard parameters of the borer tools (depending upon the rock physical and mechanical properties at the mine face), and to implementing drill bit adaptation with complete or partial rearrangement of its structure accomplished through introduction of elastic elements. The paper objective is rationale for choosing an elastic element for an adaptive cutting bit, and its parametrization.

Materials and Methods. Experimental research was carried out using a real adaptive cutting bit (dia. 160 mm) with rubber samples having various parameters. For testing, rubber samples with the following varied properties were selected: rubber hardness (Shore scale) 40 to 75 ea; sample height 25 to 60 mm; operating range of pressure load 5 to 30 kN; sample shapes solid parallelepiped, parallelepiped with lateral grooves, perforated parallelepiped, layered parallelepiped with layers ranging from 6 to 15 mm. Based on the experimental results, a comparison was carried out with validation of the most suitable elastic element type and its parameters.

Research Results. Findings of the experimental study on elastic elements for adaptive cutting bits are presented. Following the comparison of the most common shapes of shock dampers, it is established that a multi-layered element serves best as an adapting joint.

Discussion and Conclusions. Using rubber-based elastomers as elastic elements in adaptive cutting bits appears to be feasible for low diameter cutters. Recommendations are provided regarding rubber hardness, layer thickness, and total height of the elastic element for the specified stroke length values of the adaptive drilling bit blade.