Patent ID: 7377339
Filing Date: 2008-05-27
Classification: E21B,F16F

Abstract:
1. A torsional bearing assembly for use in a drill string for transmitting torque from a source of torque to a drill bit and for converting torsional vibration of the drill bit into axial vibration, comprising: a first member capable of being mechanically coupled to the source of the torque so that the first member rotates in response to the torque, the first member having a first groove formed therein; a second member capable of being mechanically coupled to the drill bit so that the drill bit rotates in response to rotation of the second member and so that torsional vibration of the drill bit is imparted to the second member, wherein the second member is mechanically coupled to the first member so that the second member can translate in relation to the first member in a first direction substantially coincident with a longitudinal centerline of the torsional bearing assembly, and the second member has a second groove formed therein that faces the first groove so that the first and second grooves form a passage extending substantially in a second direction; a ball bearing disposed in the passage for transmitting the torque between the first and the second members; and wherein the second direction in which the passage extends is angled in relation to the longitudinal centerline of the torsional bearing assembly so that at least a portion of the motion in both the clockwise and counterclockwise directions associated with the torsional vibration imparted to the second member from the drill bit is transferred to the first member as axial vibration substantially coincident with the longitudinal centerline of the torsional bearing assembly.