Ball Screw Device

摘要

A ball screw device includes: a threaded shaft; a nut; multiple first balls rollably arranged on a helical raceway composed of a helical groove of the threaded shaft and a helical groove of the nut; an inner ring raceway groove formed on an outer circumferential surface of one axial end of the threaded shaft; an outer ring having an outer ring raceway groove that faces the inner ring raceway groove; and multiple second balls rollably arranged between the inner ring raceway groove and the outer ring raceway groove. The ball screw device converts rotation of the threaded shaft into linear motion of the nut through the first balls rolling on the helical raceway while being subjected to a load. The outer ring has a rolling element insertion hole penetrating from its outer circumferential surface to the outer ring raceway groove and a lid configured to cover the rolling element insertion hole. An inner surface of the lid is formed into a concave shape to serve as part of the outer ring raceway groove.