US Patent 9458871 Structure for shaft, male member, and female member

A shaft structure including: a male component having male spline parts and male spline bottom parts on an outer peripheral part; a female component having female spline parts and female spline bottom parts on an inner peripheral part configured to allow the male component to be slidably inserted in an axial direction; and an elastic member arranged on the male component covering a surface of the outer peripheral part of the male component, wherein, in an initial state where the male component is inserted into the female component, the female and male components have first gaps between: sides of the female spline parts; and sides-facing portions of the elastic member, and when the male component is rotated, a time from the initial state to a state where the sides of the female spline parts abut on the portions of the elastic member, has predetermined time differences along the axial direction.