Tubular threaded joint with trapezoid threads having convex bulged surface

摘要

The present invention relates to a tubular threaded joint comprising a male element (1) and a female element (2) one screwed into the other with a specific torque wherein at least one thread surface under contact pressure (125) has prior to being screwed a continuous convex bulged shape over its bending radius (R1) length ranging between 2 and 60 mm and is in point-to-point contact with the corresponding surface (26) of the conjugate element thread. Such a threaded joint exhibits enhanced screwing and unscrewing strength. In one embodiment, the convex bulged surface (125) is a male or female thread flank and one of the male or female threads comprises a groove (31) emerging at the thread crest (29) to make, as the case may be, either the convex bulged flank (125) or the corresponding flank flexible. Such geometry enables to accommodate contact variations between the flanks.