Antiseizure plain bearings - particularly with double bearing surface in rotary drilling bits

摘要

In a plain bearing for ensuring rotation of one part, e.g. a rotary cutter for drilling a borehole, having an internal cavity of hard abrasion-resistant metallic relative to a second part forming a journal and having an external bearing surface also of hard and abrasion-resistant material, comprising a ring consisting of at least one element, mounted freely in the annular space between the cavity in the first part and the journal, the ring has at least one external bearing surface and at least one internal bearing surface fabricated in a hard metallic material and at least one external surface composed of at least one metal endowed with anti-seizing properties, particularly a soft metal selected from Ag, Ge, In, Sn, Sb, Tm, Pb, Bi, Cd, Cu. Ensures a long length of life for a plain bearing particularly for use in a drilling tool, with much reduced risk of seizure.