High-pressure fuel injection pipe

摘要

A high-pressure fuel injection pipe has a connecting head portion increased in diameter by buckling molding at the end of a thick and small-diameter metallic pipe. An under-head portion of the connecting head is formed with a thick wall portion that satisfies conditions of: a radius of curvature R1 of a portion A of the thick wall portion continuing to the connecting head is 0.03 to 0.15 times the outer diameter of the pipe; a radius of curvature R2 of a portion B continuing from the portion A of the thick wall portion to a straight pipe portion is 0.3 to 1.5 times the outer diameter of the pipe; and a maximum diametrical size w of the thick wall portion is 0.25 to 0.4 times a maximum diametrical projecting length W of the connecting head.