Patent ID: 8181549

Claim:
A steering apparatus comprising: a drive source which supplies an auxiliary force; and a reduction mechanism which transmits the auxiliary force of the drive source to a steering system and comprises: a worm gear having a single thread tooth; and a worm wheel engaging with the worm gear, wherein a plane orthogonal to an axial direction of the worm gear is defined as (W), a tangent line at an engagement point A between the worm gear and the worm wheel, which appears in a cross section (W-W) of the worm gear along the plane (W), is defined as (C), a rotation center of the worm gear is defined as (D), and a straight line, which passes through the rotation center (D), which is parallel to a straight line perpendicular to the tangent line (C), and which is located on the plane (W), is defined as (E), the worm gear has a shape in which the straight line (E) intersects with an outer periphery of the tooth of the worm gear on the plane (W).