A supporting structure of ball screw shaft

摘要

One object of the present invention is to provide a supporting structure of a ball screw shaft which can reduce its manufacturing cost and size as well as improve the durability and reliability. According to the present invention there is provided a supporting structure of a screw shaft (7) of a ball screw (3) in which the screw shaft is rotationally supported relative to a housing (4) via supporting bearings (10,11) such that fitting portions (13,14) and shoulder portions (19) are formed on both ends of the screw shaft and the supporting bearings are press-fitted onto the fitting portions via a predetermined interference.