| 摘要 |
PROBLEM TO BE SOLVED: To improve fatigue strength of inner pressure by using an elliptical cross sectional elliptical pipe for the main pipe rail of a common rail being a high pressure fuel branch pipe in a diesel internal combustion engine, and arranging a completely round cross sectional branch hole in the short diametral part of the elliptical pipe so as to be matched with the position of a center in the long diametral direction of the flowing passage of the main pipe rail. SOLUTION: An elloptical cross sectional elliptical pipe is used for a main pipe rail 1 being a common rail, and the axial inner part of the elliptical pipe is formed in a flowing passage 1-1, and also a completely round branch hole 1-2 which is formed of a completely round hole communicated with the flowing passage 1-1 and whose circumferential surface outwardly opened is made to serve as a pressure receiving seat surface 1-3, is arranged on the center of the long diametral direction of the flowing passage 1-1. A branch pipe 2 which has a channel 2-1 communicated with the flowing passage 1-1 in its inside and in which a pushing/pressing seat surface 2-3 having a connecting head part 2-2 is arranged at its end part, is attached to the thusly formed main pipe rail 1 by connecting a nut 4 to the sleeve nipple 3a of a joint part 3. Hereby, occurrence of stress in a branch hole part can be effectively suppressed, and fatigue strength of inner pressure in each branch pipe mounting part can be improved. |
