AZIONATORE A VITE CON CIRCOLAZIONE DI SFERE.

摘要

A spindle or leadscrew and an associated nut, forming part of a driving assembly of the circulating-ball type, have helical threads of symmetrical profiles in the shape of pointed arches whose flanks engage the recirculating balls along respective helical contact lines. With the spindle virtually non-deformable in the axial direction, the pitch of its thread exceeds that of the nut thread (in the absence of stress upon the latter) by a small differential-specifically 0.02%-lying well within the limits of elastic axial deformability of the nut. Upon rotation of the spindle relative to the nut for the transmission of an axial force, this differential results in an approximately uniform stress distribution among the sets of balls lying in confronting turns of the spindle and nut threads.