ASSEMBLING METHOD OF BALL SCREW IN ELECTRICALLY DRIVEN POWER STEERING SYSTEM

摘要

PROBLEM TO BE SOLVED: To provide the assembling method of a ball screw in an electrically driven power steering system that can cope with change in the electric motor characteristics by simplifying installation of the ball screw to the armature assembly. SOLUTION: In the assembling method of a ball screw 8 interposed between one end of a hollow shaft and a steering shaft 4 inserted into the hollow shaft 9 that defines a rotating shaft of an electric motor 7, a plurality of recess grooves 9b are notched at one end portion (expanded diameter) of the hollow shaft. A flanged cylinder 21 having protrusions 21a respectively fitted to the recess grooves 9b is brought into abutment and engagement with one end of the hollow shaft. A flange 21b of the flanged cylinder is fixed on the end surface of a yoke 6 of the electric motor such that one end of the hollow shaft is subjected to detent relative to the yoke of the electric motor. Then a nut 10 of the ball screw is fitted to a nut holding portion 9a of the hollow shaft by tightening.