| 摘要 |
There is provided a common rail which can reduce a maximum stress value generated in an inner peripheral edge portion of a lower end of a branch hole and can further improve an internal pressure fatigue strength. In the common rail comprising at least one branch hole provided on a peripheral wall portion of a main pipe rail having a communication passage inside an axial core, a pressure receiving seat surface communicating with a branch pipe having a communication passage communicating with the communication passage in a peripheral surface portion of the branch hole and open to an outer portion, thereby bringing a pressing seat surface portion constituted by a connection head portion disposed in an end portion of the branch pipe into contact and engaging therewith, and a joint portion integrally or separately provided in the main pipe rail and a nut previously assembled in the branch pipe end which are meshed with each other so as to be pressed under a neck portion of the connection head portion, thereby being fastened and connected, the main pipe rail has an outer peripheral surface substantially formed in a circular shape, and at least an adjacent portion to the branch hole of the inner peripheral surface is slightly projected or flattened so as to be formed in a vertical cross section of a not complete round shape. |
