Torsional bearing assembly

摘要

A torsional bearing assembly 14 for use in a drill string can transmit torque form a source of torque to a drill bit and can convert torsional vibration of the drill bit into axial vibration. This is achieved by having a first member 52 coupled to the source of torque and which rotates in response to the torque. The first member includes a groove 70. A second member 50 is coupled to the drill bit and rotates the drill bit and that torsional vibration of the drill bit is imparted to the second member 50. The first and second members 50, 52 are connected such that they can translate relative to each other. The second member 50 also includes a groove 74 which forms a passage 78 with the groove 70 of the first member 52. A ball bearing 55 is disposed in the passage 78 for transmitting torque between the first 52 and second 50 members. The passage 78 is angled in relation to the centreline of the torsional bearing assembly 14 so that a portion of the torsional vibration imparted to the second member 50 from the drill bit is transferred to the first member 52 as axial vibration.