| 摘要 |
PROBLEM TO BE SOLVED: To naturally engage an electric motor or a bearing inner ring in an outer diameter part of a rotary nut of a ball screw mechanism, eliminate generation of a seam in an inner surface of the rotary nut, achieve smooth circulation of balls, and prevent generation of scraping a lubricating film. SOLUTION: In this device, a part of a steering shaft 2 which freely advances or retracts is set as a ball screw shaft 2a of a ball screw mechanism, and a rotor 10 of an electric motor 8 for compensating steering force is engaged with a rotary nut 14. The rotary nut 14 is integrally formed, instead of a piece in which a conventional adjacent groove parts of an inner screw groove 18 are connected with a return groove 19 provided in the piece, by changing the piece with the whole body of the nut 14. |
