SPEED REDUCER OF AN ELECTRIC POWER ASSIST STEERING SYSTEM AND AN ELECTRIC POWER ASSIST STEERING SYSTEM USING THE SAME CAPABLE OF ABSORBING VIBRATION AND NOISE BY FRICTION AND ABRASION WHEN A WORM AND WORM WHEEL OPERATE

摘要

PURPOSE: A speed reducer of an electric power assist steering system and an electric power assist steering system using the same are provided to reduce rattle noise caused by an increase in backlash due to abrasion of a worm and a worm wheel, or, an impact transferred through a wheel and a steering shaft from a road surface, and to increase the steering feel of a driver by reducing the notch feeling and rotational resistance of a worm shaft and a worm shaft bearing. ;CONSTITUTION: A speed reducer of an electric power assist steering system comprises: a worm shaft(254) having a worm(152) at the center, a worm shaft bearing(257) supporting rotation on two ends, and a vibration-proof member(320) on the outer circumference of one end or two ends coupled with the worm shaft bearing; a gear housing(260) accommodating a gear mechanism including the worm shaft, the worm shaft bearing and the worm wheel; and a damper(330) coupled between the opposite end of a connection of a motor shaft(305) of the worm shaft and the gear housing to support the worm shaft in the axial direction.;COPYRIGHT KIPO 2011