Patent ID: 8881185

Claim:
A rotary element assembly structure in which a rotary element is assembled to a tip side of a hollow shaft provided upright on a pedestal so that the rotary element is capable of rotating about the hollow shaft, wherein the rotary element is provided with, at its rotation center portion, a cylindrical portion having an inner circumferential portion fitted with an outer circumferential portion of the hollow shaft; the cylindrical portion is provided with, in its inside, a hook strut portion having a hook portion overhanging in a radial direction on its tip side and extending substantially along a fitting direction to the hollow shaft; and a base end portion of the hook strut portion and a base end portion of the cylindrical portion are coupled to each other by a resin-made thin plate portion, wherein the hollow shaft is provided with, at its tip side, a small diameter portion smaller in diameter than a hollow portion of the hollow shaft; a radius of an overhang tip portion of the hook portion is set to be greater than a radius of the small diameter portion of the hollow shaft and to be smaller than a radius of the hollow portion, and when the rotary element is assembled to the tip side of the hollow shaft, the cylindrical portion of the rotary element is fitted with the hollow shaft, whereby the hook portion on the tip side of the hook strut portion is pushed into the hollow portion via the small diameter portion on the tip side of the hollow shaft, and the hook portion engages with a stepped portion formed by the hollow portion and the small diameter portion.