| 摘要 |
Provided is a ball screw device for reducing runout of the end part of a screw shaft even when the screw shaft is under an excessive load. To achieve this, a ball screw device (1) has a screw shaft (10) having a helical groove (11) formed in the surface thereof, a bearing (20) and an enlarged-diameter member (50) for supporting a bearing installation part (10a) formed in the end part of the screw shaft (10), and a spacer (60). The enlarged-diameter member (50) comes in contact with an end surface with which the helical groove (11) is interconnected, forming an annular shape that can be divided in the axial direction into a plurality of divisions. The spacer (60), which covers at least part of the enlarged-diameter member (50), is fitted in between the axial end surface of the enlarged-diameter member (50) and an inner ring (21) of the bearing (20). |
