FIELD: mining.
SUBSTANCE: group of inventions relates to a drill string component for percussive drilling and a threaded joint thereof. Device in a drill string component includes a thread for threading together with another drill string component provided with a complementary thread. Thread includes a thread groove (9) formed by two thread flanks (10, 11), whereof one in operation forms a pressure flank, and an intermediate thread bottom (12). Thread groove (9) has an essentially equally shaped sectional form along its length. Thread bottom (12) comprises at least three surface portions (Y1, Y2, YC) with part-circular shape, as seen in an axial section, and surface portions (Y1, Y2, Y3) with part-circular shape have increasing radii from each thread flank to an intermediate surface portion of thread bottom. Invention also relates to threaded joint and a drill string component.
EFFECT: increased resistance of threaded joint to fatigue stresses.
19 cl, 16 dwg
