Power steering system

摘要

A power steering system includes a first R-shaped portion formed with a cylindrical wall and curvedly extending from an outer-periphery general face of the cylindrical wall to the outer periphery of a butt wall, and a second R-shaped portion formed with the cylindrical wall and arranged between the butt wall and the first R-shaped portion, wherein the second R-shaped portion is smaller in radius of curvature than the first R-shaped portion.