Linear feed mechanism

Abstract

A linear feed mechanism includes a track member, a moving member movably supported on the track member through a linear motion bearing mechanism, and the moving member is moved relative to the track member by a threaded ball screw shaft. There is a smooth elongated semicircular groove in one face of the track member, a corresponding spirally threaded semicircular groove in the moving member and these two semicircular grooves jointly define a substantially circular through hole. The threaded ball screw shaft is in the through hole, and ball bearings are in between the threads of the threaded ball screw shaft and the spiral thread of the moving member, between the threads of the threaded ball screw shaft and the smooth surface of the semicircular groove of the track member, and also in a ball bearing circulating passage extending from one part of the spirally threaded surface of the moving member to another part thereof for causing ball bearings to move from one part of the threads to another when the threaded ball screw shaft is rotated for causing the moving member to move linearly relative to the track member. A second ball bearing tube can provide additional enhanced operation, slidable support of the moving member on the track member, and improved sliding and linear motion accuracy of the linear feed mechanism.