(B1) ;ROLLER BIT WITH INCREASED NUMBER OF CUTTING ROLLERS

摘要

A rotary drill bit assembly comprising a trunnion and at least one rotary cutter mounted on the trunnion. The trunnion is supported by bearings including at least one radial bearing and at least one axial roller bearing. The axial bearing is comprised of conical rollers and one of the races for this bearing is disposed perpendicular to the axis of rotation of the rotary cutter and the complementary bearing race is conical. A guide rim is associated with one of the bearing races which guides the conical rollers in a radially outward direction.