US Patent 10145420 Joint structure and joining method thereof

A joint structure includes a shaft member and a cylindrical member. The cylindrical member includes a plurality of first crimped portions crimped along a plurality of axial grooves provided in an axial direction of the shaft member, respectively, and a second crimped portion which fits the axial grooves and is crimped along a circumferential groove, the circumferential groove being provided on a circumferential surface of the shaft member by reducing a diameter of an axially intermediate portion of the cylindrical member in a radial direction. Each of the first crimped portions project from an inner circumferential surface of the cylindrical member as a projection. A position of a tip of the projection in an axis direction of the projection is set displaced from a position of a lowest point of the circumferential groove such that the tip is not located at the lowest point of the circumferential groove.