| 摘要 |
PROBLEM TO BE SOLVED: To provide a double nut type ball screw device having good operability and facilitating a preload adjusting work.SOLUTION: A ball screw device 10 includes a screw shaft 1 forming a ball rolling groove 9 in an outer peripheral surface, a plurality of nuts 3a and 3b forming ball rolling grooves 8 corresponding to the ball rolling groove 9 of the screw shaft 1 in inner peripheral surfaces, a plurality of rolling balls 2 interposed by a track formed by the screw shaft 1 and the ball rolling grooves 8 of the nuts 3a and 3b, and preload applying means 20 applying preload by making axial direction forces of opposite directions act on the plurality of nuts 3a and 3b. The preload applying means 20 includes a plurality of preload balls 7 interposed between two adjacent nuts 3a and 3b, and a preload ball holding tool 6 which is a disc-shaped elastic member having thinner plate thickness than outer diameters of the preload balls 7 and forms storage sections 6a at four or more portions so as to elastically hold the preload balls 7. |
