| 摘要 |
<p>The threads each have a bearing flank (10, 5) extending perpendicular to the thread axis and the radial force contact zones (15) are spaced radially from the envelope (E) of the bases of the male threads and form an angle of less than 40 deg. with the thread axis. A male element (1) with a conical male thread (3) and a female element (2) with a conical female thread (4) screw together. The radial force contact zones are formed by (i) the summit of at least one helical protrusion formed in the base of at least one of the threads relative to the thread base envelope and (ii) the summit of the corresponding thread. The protrusions are in the base of the male thread and the summit of the protrusions are convex domes. The protrusions are connected to the bottom of the thread by one or more concave circles. Each protrusion is made of the summit of a helical spine (14) formed in the bottom of the thread (13). The radial force contact zones comprise the summits of at least two helical spines in succession axially along the bottom of the male thread, and correspond to a hollow helix in the summit of the corresponding thread which partially envelops each spine. The height of the protrusions from the bottom of the thread are between 0.2 and 0.4mm. Alternatively, the radial force contact zones include the summit of a boss extending from the bottom of the bearing flank to the bottom of the engaging flank, or pressing on one of the flanks. The contact zone can be formed by a slope or intermediate region on the flank at a smaller angle to the thread axis than the rest of the flank. The angle of the contact zone to the thread axis is between 20 and 40 deg., preferably 27 deg. The contact zone can be formed by a concave rounding or pair of roundings in the male thread flank.</p> |
