Ball screw and nut assembly

摘要

A ball screw nut assembly of the type in which a nut having an internal helical groove is telescoped over a shaft having an opposing helical groove and an endless train of balls is disposed in the grooves so that the nut travels axially along the shaft as the latter is turned relative to the nut. Travel of the nut along the shaft is limited by a stop which is mounted on the shaft and engaged by the nut. As the nut approaches the stop, the balls leave the groove in the shaft and roll on a cylindrical portion of the shaft whereby the nut is no longer positively driven and the force with which the nut impacts the stop is substantially reduced. Return of the balls into the groove on the shaft is aided by making the diameter of the cylindrical portion slightly greater than the root diameter of the shaft grooves and by utilizing a resilient stop.