US Patent 12025244 Inner ring and pipe joint

An inner ring of a pipe joint includes a first tapered surface formed at one axial end portion of an inner circumferential surface such that a diameter thereof gradually increases from another axial side toward one axial end thereof in a state before a bulge portion is press-fitted into an end portion of a tube. A diameter increase starting point of the first tapered surface is located in a range from a deformation starting point, which serves as a starting point from which an inner circumferential surface is deformed due to the bulge portion