Patent ID: 8813904
Filing Date: 2014-08-26
Classification: B62D,F16C,F16H

Abstract:
1. An electric power steering system, comprising: a worm reducer including a worm shaft that has a first end portion and a second end portion and that is supported so as to be pivotable about the first end portion, and a worm wheel that is in mesh with the worm shaft, the worm reducer reducing a speed of rotation of an electric motor for assisting a steering operation; and an urging mechanism that elastically urges the second end portion of the worm shaft to adjust a backlash between the worm shaft and the worm wheel, wherein the urging mechanism is configured to adjust the backlash by elastically urging the second end portion in one of perpendicular directions that are perpendicular to a direction in which an inter-axis distance between the worm shaft and the worm wheel increases and decreases, in a state where an increase and a decrease in the inter-axis distance are prevented, and wherein an urging direction of the urging mechanism is a direction in which a lead angle of the worm shaft becomes smaller than a lead angle of the worm wheel, and which is the one of the perpendicular directions.