BALL SCREW DEVICE

摘要

A ball screw device (10) capable of increasing a load capacity by increasing the size of ball diameter and the number of threads by preventing the cutout of a nut from being interfered with a thread groove adjacent to the cutout even in the thread groove of a small lead screw and a multiple thread screw, wherein a circulating block (18) forming, in association with the cutout (17), a ball (15) circulation passage (21) for communicating an area between both thread grooves (11) and (13) with a ball return passage (16) is fitted to the cutout (17) formed at the end of the nut (14) so that the large number of balls (15) can be endlessly circulated between both thread grooves (11) and (13), ball circulation passage (21), and ball return passage (16). The face of the cutout (17) facing the axial direction thereof is used as a ball running surface (23), a ball circulating groove (20) is formed at the portion of the circulation block (18) opposed to the ball running surface (23), and the ball circulation passage (21) is formed of the ball circulating groove (20) and the ball running surface (23).