THREE-CONE ROLLING DRILLING BIT

摘要

FIELD: mining. ^ SUBSTANCE: invention concerns rock destruction tool, and namely small-diametre rolling drilling bits. Three-cone rolling drilling bit includes legs with trunnions on which there installed are cutters mounted by means of ball bearing and reinforced with hard-alloy teeth fixed on trapezoidal rows of cutters. Hard-alloy teeth are installed perpendicular to working platforms of the rows. Distance from bit axis to axis of hard-alloy teeth on rows of generatrixes of the main cone of cutter is determined by mathematical formula. ^ EFFECT: increasing operating efficiency of the bit owing to tighter covering of the bottom hole with hard-alloy teeth on the main rows of cutters. ^ 1 dwg