| 摘要 |
PROBLEM TO BE SOLVED: To provide a ball screw device having a small gap between a top member and a screw groove of a screw shaft and an electric power steering device using the ball screw device. SOLUTION: The ball screw mechanism 26 used for the electric power steering device comprises a ball rolling passage 68 formed with a screw groove 34 of a rack shaft 12 and a screw groove of a ball screw nut opposed to each other and a circulation groove 76 provided in the top member 74 striding over a screw crest 34A in communication with the ball rolling passage 68 adjacent thereto in the axial direction, whereby a circulation raceway is formed in an approximately circular shape, and balls 70 and separators 71 are alternately arranged. Closing members 80A, 80B entering the screw groove 34 are provided extendingly in groove walls 78A, 78B of the top member 74, with a small gap C provided between the top member 74 and the screw groove 34. Thus, the deviation of the separators 71 via the gap C is prevented. COPYRIGHT: (C)2004,JPO |
