| 摘要 |
PROBLEM TO BE SOLVED: To provide a ball screw device that maintains high accuracy, without significantly increasing cost or causing heat treatment deformation.SOLUTION: A ball screw device 1 has a screw shaft 10 having a ball rolling groove 11, a nut 20 having a ball rolling groove for constituting a load rolling passage together with the ball rolling groove 11, a plurality of balls loaded in the load rolling passage formed of the ball rolling groove 11 and the ball rolling groove of the nut 20, and a circulating tube 40. A second flat surface 23 is arranged on the side opposite a first flat surface 22 of the nut 20 so that cross sections S1 and S2 cut by a surface S orthogonal to the first flat surface 22 and including the axial center O of the nut 20, are substantially line symmetrical to each other. No circulating tube 40 is arranged on the second flat surface 23. |
