Patent ID: 8043023

Claim:
A power transmission mechanism comprising a shaft and a hub, the power transmission mechanism further comprising: a shaft tooth section formed on the shaft; a hub tooth section formed on the hub; and a retaining ring, wherein the hub is axially secured relative to the shaft by the retaining ring in a position disposed around the shaft while holding the shaft tooth section and the hub tooth section in engagement with each other, wherein said shaft tooth section has a straight peak having a constant tooth thickness and a valley having an outside diameter varying from an end of the shaft toward a shaft shank of the shaft, said valley having a step region sloped toward said hub tooth section obliquely at a predetermined angle, wherein a valley radius of said shaft tooth section representing a distance from a central axis of the shaft to a bottom land of said valley is constant from the step region to the end of the shaft; and said hub tooth section has a straight peak opposing the step region of said shaft tooth section, and opposing and engaging said valley of said shaft tooth section, said peak of said hub tooth section having a constant tooth thickness and a valley, said peak of said hub tooth section has a constant inside diameter (φD 3 ) which radially opposes the valley and step region of the shaft tooth section from the end of the shaft toward said shaft shank in an axial direction of the shaft.