| 摘要 |
<p>PROBLEM TO BE SOLVED: To increase the strength of a rail inside surface without depending on the form of a passage by forming the inner surface of the passage for passing a high-pressure fuel in a high pressure fuel rail formed of a thick and slender metal pipe by the residual surface of a compression stress. SOLUTION: A pipe body formed of a thick and slender steel pipe or forge product having a diameter of 20mm or less in which a passage 1' is perforated is used as a rail material, and a branched pipe 3 or various mounting ports are worked on the rail material. A proper position of the rail material having the mounting port worked thereon is sealed to fill it with a fluid such as oil as pressure medium, and a pressure of yielding 25%-75% of the thickness of the rail material is applied to the whole inside surface (the whole surface of the passage 1') by the fluid pressurized to a high pressure by a high pressure pump. After this pressurization, the high pressure fluid is removed, and a compression stress is left on the whole surface (the inside surface of the passage 1' and the inside surface of a through-hole 2') within the passage 1' of the rail material. Thus, the fatigue strength of the rail inside surface is increased, and the durable life can be extended.</p> |
