TORSIONAL SHOCK ABSORBER FOR A DRILL STRING

摘要

A torsional shock absorber dampens rotary shock loading on a well drill string. An outer housing has drive splines on an inner surface. A mandrel is located within the outer housing and has drive splines on an outer surface that fit between the drive splines on the inner surface of the housing. Dampening bar s are positioned longitudinally between the splines of the outer housing and t he splines of the mandrel to absorb shock from non-uniform torsional loading at the drive interface between the outer housing and the mandrel. A balancing pisto n is located within the tool to compensate for pressure difference between drilli ng fluid pressure and lubricant contained within the shock absorber. A thrust bearing assembly is provided to accept axial thrust loads from the outer housing and transfers the load to the splined mandrel. A retainer transfers tensile load s from the housing to the mandrel through the thrust bearing.