Patent ID: 7537080

Claim:
An electric power steering apparatus, comprising: an electric motor for generating a steering assist force; a reduction gear mechanism for reducing a rotation speed of an output shaft of the electric motor; a conversion mechanism for converting an output rotation of the reduction gear mechanism into an axial movement of a steerable shaft extending in a transverse direction of a vehicle, the reduction mechanism comprising: an inscribed gear having external teeth and being rotatable interlockingly with the output shaft of the electric motor; a circumscribed gear having internal teeth in which the inscribed gear is inscribed; a driving pulley integrally rotatable with the circumscribed gear, the driving pulley being in the shape of a cylinder and having a first end portion and a second end portion, the first end portion of the driving pulley being closer to the output shaft of the electric motor than the second end portion, and at least the first end portion of the driving pulley being opened, a driven pulley disposed so as to surround the steerable shaft; an endless belt for connecting the driving pulley and the driven pulley, and an input shaft for transmitting a driving force through the inscribed gear and the circumscribed gear to the driving pulley; a housing for containing the inscribed gear, the circumscribed gear and the driving pulley, and a driving pulley support means held by the housing for supporting the driving pulley in a cantilever manner and rotatably about a central axis line of the driving pulley, wherein a support shaft is formed as extending from the second end portion of the driving pulley along the central axis line of the driving pulley, and the driving pulley support means comprises a bearing for rotatably supporting the driving pulley through the support shaft.