HIGH-PRESSURE FUEL INJECTION PIPE HAVING CONNECTION HEAD

摘要

PROBLEM TO BE SOLVED: To provide a high-pressure fuel injection pipe having a connection head which can prevent the plastic deformation of a connection washer (a washer or a sleeve washer) to thereby obtain high sealing performance. SOLUTION: The connection head having an outer peripheral surface serving as a seat surface corresponding to its mated seat member is provided at the connection end portion of a thick steel pipe having a relatively small diameter. An annular concave channel section which is generated on the inner side of the head when forming the connection head is made to have a small depth and a gently-sloping shape. The connection washer is fitted on the outer peripheral surface at the neck lower portion of the connection head. In the high-pressure fuel injection pipe constituted as described above, a stair-like stepped portion having at least two or more steps without any slant portions is provided on the outer peripheral surface at the neck lower portion of the connection head. A stair-like stepped portion wholly or partially corresponding to the stair-like stepped portion of the connection head is provided on the inner peripheral surface of the connection washer so that the connection head and the connection washer are made in contact with each other. COPYRIGHT: (C)2004,JPO&NCIPI