ASSEMBLING METHOD OF BALL SCREW IN ELECTRICALLY DRIVEN POWER STEERING SYSTEM

摘要

PROBLEM TO BE SOLVED: To provide the assembling method of the ball screw in an electrically driven power steering system capable of reducing the number of assembly steps and coping with the change in the electric motor characteristics by simplifying assembly of the ball screw to the armature assembly. SOLUTION: A rotation shaft of an electric motor 7 for outputting steering auxiliary force is formed by a hollow shaft 9. A steering shaft 4 is inserted into the inside of the hollow shaft 9. A ball screw 8 is interposed between one end of the hollow shaft and the steering shaft 4, through which the steering auxiliary force is transmitted from the electric motor 7 to the steering shaft 4. In this method, a lock pin 21 is inserted from the outside into the one end of the hollow shaft 9 and a yoke 6 of the electric motor 7 such that the one end of the hollow shaft 9 is subjected to detent relative to the yoke 6 of the electric motor 7. Then a nut 10 of the ball screw 8 is fitted with a nut holding portion 9 at the one end of the hollow shaft by tightening.