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Title: Downhole drill bit drive apparatus

Patent ·
OSTI ID:6185198

This patent describes a downhole drill bit drive apparatus having a tubular housing adapted to be secured to the downhole end of a drill string. A mandrel concentrically is disposed within the housing and has one end adapted to be secured to a downhole rotary drive means and another end adapted to be secured to a drill bit. A bearing means is disposed between the housing and the mandrel to permit rotation of the mandrel with respect to the housing and transmit axial and radial loads between the housing and the mandrel. The housing and the mandrel defining a fluid flow passage for transmitting drilling fluid to a drill bit secured to the mandrel, the improvement comprising: a first seal means which includes an annular piston chamber, the housing defining an outer wall of the piston chamber and the mandrel defining an inner wall of the piston chamber. One end of the piston chamber communicates with the fluid flow passage. The other end of the piston chamber communicates with the bearing chamber, annular piston means is concentrically disposed within the piston chamber in sealing engagement with the inner and outer walls of the piston chamber. The piston means is axially movable in the piston chamber in response to a pressure differential between the fluid pressure in the fluid flow passage and the fluid pressure in the bearing chamber to a position where the fluid pressures are substantially equal. Roller bearing means rotates mounting the piston means on the mandrel to permit rotation of the mandrel with respect to the piston.

Assignee:
Maxi-Torque Drill Systems, Inc., Edmonton, CA
Patent Number(s):
US 4683964
OSTI ID:
6185198
Resource Relation:
Patent File Date: Filed date 25 Oct 1985
Country of Publication:
United States
Language:
English