Patent ID: 6126208
Filing Date: 2000-10-03
Classification: B21C,F02M,Y10T

Abstract:
A common rail comprising a main pipe rail having an axially extending peripheral wall, said peripheral wall having an inner surface defining an axially extending communication passage, said inner surface being substantially cylindrically generated along major portions of said main pipe rail, at least one branch hole extending transversely through the peripheral wall and communicating with the communication passage of the main pipe rail, a pressure receiving seat surface formed in a peripheral surface portion of said branch hole and open to an outer portion of said main pipe rail for receiving a connection head portion disposed in an end portion of a branch pipe, and a sleeve nipple attached to the main pipe rail by welding or brazing, said sleeve nipple being for engagement with a nut previously assembled on the branch pipe for pressing said connection head portion against said pressure receiving seat so that the branch pipe and the main pipe rail are fastened and connected, a compression residual stress being produced in portions of the peripheral wall adjacent to the branch hole of the main pipe rail by applying a radial inward pressing force to outer peripheral surface regions of the peripheral wall surrounded by the sleeve nipple, said pressing force being sufficient to define a substantially planar surface area on the inner surface of the peripheral wall surrounding the branch hole, the planar portion of the inner surface of the peripheral wall intersecting the cylindrically generated portions of said inner surface.