Modeling of “combined cutter - cone” connection in tricone drill bits

Abstract

A theoretical analysis of the stiffness of the “cutter-cone” connection was performed. In the article the character and magnitude of the tension at the contact of "cutter-cone" are investigated. An analysis of the surface of the openings for carbide inserts revealed traces of plastic deformation and fretting wear. Since the contact bond of the cutter with the body of cone is the only factor that provides the strength of the connection, let consider the effect of mechanical properties of the cones body and a cutter on the magnitude of the forces of contact and tension in the connection. The surface of the shaft of this design consists of equal parts of solid alloy and steel. If you make a ring at a smaller diameter of the shank of a carbide cutter, this will increase the reliability of the connection of the insertion with the body of the rock cutting tool, optimize toughness of cutter fastening, and ensure high stability of the hard-alloyed inset cutter before fracture. As a result of the conducted researches, a qualitative correlation between the hardness of the carbide insertion fastening in the holes of cone and the nature of the destruction of the carbide cutters has been established. Due to the conducted research, the character of the distribution of contact tensions in the conjugated areas “combined cutter - a hole of cone” was established. The theme of the development of new rational constructions of rock-destructive equipment of cones, rock-destructive inserts, schemes of its effective arrangement on the brushes of cone is still actual. A separate issue of further research is the study of functional and energy interaction of elements of propulsion and rock-destructive equipment.