Patent attributes
A pipe-connecting device includes: an inner ring having: an outer circumferential portion having a tip-contracted outer-circumferential flared surface that is to be press-inserted into an end portion of a tube to flare the tube, and an inner circumferential portion constituting a fluid transfer path; a pipe joint body that has a tubular screwing portion having an external thread; and a union nut having an internal thread that is screwed with the external thread. The inner ring including the tube is inserted into the tubular screwing portion, and the tip-contracted outer-circumferential flared surface is pressed through the tube by a pressing portion of the union nut. The pressing portion of the union nut is formed into an inclined inner circumferential surface that is inclined in the same direction as the tip-contracted outer-circumferential flared surface with respect to the axis of the tubular screwing portion.