Patent ID: 8893847

Claim:
An electric power steering system including a rack shaft that is supported so as to be able to make a reciprocating motion in an axial direction of the rack shaft, a hollow shaft through which the rack shaft is passed and which is rotated by driving a motor, and a plurality of bearings by which the hollow shaft is supported so as to be rotatable relative to a rack housing that accommodates the rack shaft, the electric power steering system providing an assist force for assisting a steering operation by converting rotation of the hollow shaft into a reciprocating motion of the rack shaft, the electric power steering system, comprising: elastic members that are arranged at respective axial ends of at least one of the bearings, and that elastically support the bearing relative to the rack housing in the axial direction; and a support member that is disposed on an outer periphery of the elastically supported bearing, and that supports the bearing with displacement of the bearing in a radial direction restricted, wherein the hollow shaft is disposed so as to move relative to the rack housing in the axial direction as the support member and at least one of the rack housing and the elastically supported bearing slide relative to each other, the support member includes a ring body having a plurality of spring portions formed in respective end portions of the ring body in the axial direction and arranged at given intervals in a circumferential direction of the ring body, with the spring portions being elastically deformable in the radial direction, and the support member generates a sliding resistance that corresponds to an elastic force of the spring portions.