Directional Drilling Tool

11 pages et 4 plansDirectional drilling tool (13, 14) comprising a cutting structure formed of blades on which there are cutting edges (13) and a guard (11) that stabilizes the tool against the wall of the well (3), characterized in that the guard comprises a plurality of passive pivoting blades (16) each of which can pivot about a pivot pin (18) inserted in the guard (12) near its boundary with the cutting structure under the action of thrusting and/or damping members, so that when the pivoting blades (16) are in their nominal position, the guard (12) of the tool (1, 14) exhibits a substantially cylindrical shap