| 摘要 |
PROBLEM TO BE SOLVED: To suppress generation of rattling sound by properly damping vibration (disturbance input vibration) added to a shaft of a steering force transmission mechanism by traveling on an uneven ground, etc. and transmitting the vibration to a driven gear of a speed reduction mechanism. SOLUTION: The driven gear 33 engaged with a driving gear 32 to which power of a motor 31 for steering assistance is transmitted is connected to a steering shaft 13 to be relatively rotatable in a prescribed range. An elastic member 50 to be elastically deformed by relative rotation of both of the driven gear 33 and the steering shaft 13 is provided between the driven gear 33 and the steering shaft 13. A damping region G for damping vibration in a rotating direction transmitted from the steering shaft 13 to the driven gear 33 by the elastic member 50 is provided in the relatively rotating range of the driven gear 33 and the steering shaft 13. The damping region G is made a range including amplitude of the vibration of the rotating direction of the steering shaft 13 by at least the disturbance input. A spring constant of the elastic member 50 is changed to be smaller in the damping region G and to be larger in a range exceeding the damping region G. COPYRIGHT: (C)2008,JPO&INPIT |
