Abstract: A member for a high pressure fluid or a member for a high pressure fluid with a built-in slider having higher quality which can be provided at a low price, and by which the generation of tensile stress in the lower end inner peripheral edge part of a branch hole can be canceled by compressive residual stress to be effectively restrained, the internal pressure fatigue strength in the branch hole part can be improved to be excellent in durability, prevent a fluid leakage due to the occurrence of cracks and then exhibit a sure and stable function, further only the addition of the pressing force applying process to the ordinary manufacturing process will be sufficient, and complicated equipment is not required to hardly cause the problems of an increase in the equipment cost due to an increase in the number of processes and lowering of productivity.

Abstract: There is provided a common rail which can effectively restrict a generation of a stress in a lower end inner peripheral edge portion of a branch hole and can improve an internal pressure fatigue strength in a branch pipe connecting portion, so that a secure and stable function can be obtained by having an excellent durability and preventing a fluid leakage due to a generation of the crack generation and a method of manufacturing a common rail in which a pressure application process by the press is only added to a normal manufacturing process, no complex equipment is required, a common rail having a high quality can be manufactured by a low cost without generating problems that an equipment cost is increased by an increase of the process and a productivity is reduced.

Abstract: A method is provided for manufacturing common rails, such as a high-pressure fluid manifold or a block rail that may be use in an accumulator fluid injection system. The method includes providing a main tubular rail with a flow passage extending in an axial direction. A bottomed lower hole is formed generally transverse to the axial flow passage. A pressing force is applied to the bottomed lower hole to generate a residual compressive stress in a circumferential part of the end portion of the bottom hole. The bottom lower hole then is made to communicate with the flow passage in the main rail. Defects that may have been caused by the application of the pressing force then are cut off. The removal of the defects improves an internal pressure fatigue strength, achieves high durability and ensures freedom from leakage.

Abstract: There is provided a common rail for a diesel engine in which fatigue strength against inner pressure is increased by reducing the difference in hardness or elongation between a steel surface and a nonmetal inclusion on the inner surface of, or in the surface layer of, a rail and lowering the degree of concentration of fatigue stress. The common rail includes a main pipe rail having a circulating passage extending in its inside in the axial direction thereof, branch holes formed in an axial peripheral wall portion of the main pipe rail, and branch connectors connected to the respective branch holes integrally or via separate connecting members, and a Ni-diffused fatigue strength reinforcing layer which is formed by heating a Ni layer plated in advance is formed on at least a portion of an inner circumferential surface of the common rail. The increased strength and the action of the fatigue strength reinforcing layer lowers the degree of fatigue concentration to increase fatigue strength against inner pressure.

Abstract: A hot worked steel material, such as a bar, or tube, has a surface layer improving its fatigue strength despite the non-metallic inclusions which it may contain, or the cracks which it may have. The surface layer is formed by heating a nickel layer on the steel surface to cause the diffusion of nickel therethrough.

Abstract: To provide a common rail capable of injecting fuel stably by restraining pressure variation in an injection pipe and having excellent stability of seal at a portion thereof connected to the injection pipe, in a common rail constituted by providing a branch hole having a pressure receive seat face communicating with a main pipe rail and opened outwardly at a boss portion provided at a peripheral wall portion of the main pipe rail, bringing and engaging a pressing seat face portion constituted by a connection head portion in contact with the pressure receive seat face and fastening to connect the pressing seat face portion thereto in accordance with pressing operation under a neck of the connection head portion by screwing a fastening nut, by providing an orifice pipe having an outer diameter the same as or larger than a hole diameter of the branch hole in the branch hole, the orifice pipe does not influence on seal performance and the common rail is constituted to be capable of injecting fuel stably by restrai

Abstract: There is provided a common rail which can effectively restrict a generation of a tensile stress in a lower end inner peripheral edge portion of a branch hole by canceling by means of a compression residual stress and can improve an internal pressure fatigue strength in a branch pipe connecting portion, so that a secure and stable function can be obtained by having an excellent durability and preventing a fluid leakage due to a generation of the crack generation and a method of manufacturing a common rail in which a pressure application process is only added to a normal manufacturing process, no complex equipment is required, and a common rail having a high quality can be manufactured by a low cost without generating problems that an equipment cost is increased by an increase of the process and a productivity is reduced.

Abstract: A common rail is provided for promoting inner pressure fatigue strength at location in proximity to a branch pipe. The common rail includes a main pipe rail with a main flow path. At least one boss in provided on the peripheral wall and includes a branch hole communicating the main flow path. The branch pipe is provided with a connecting head that has a pressing face at and end of the branch pipe. The pressing face of the branch pipe is urged into a pressure receiving seat of the boss. A compressive residual stress is provided at location in the peripheral wall where the main flow path of the main pipe rail communicates with the branch hole. The compressive residual stress increases the pressure fatigue strength by substantially canceling tensile stress.

Abstract: A common rail includes a generally cylindrical peripheral wall having a communication passage extending axially therethrough. At least one branch hole extends through the peripheral wall and is aligned perpendicular to the axis of the common rail. The intersection of the branch hole with the outer surface of the main pipe rail defines an outwardly flared pressure receiving seat for receiving the connection head portion of a branch pipe. A sleeve nipple is welded or brazed to the outer surface of the main pipe rail and surrounds the branch hole. Inner surface regions of the peripheral wall surrounding the branch hole have a compression residual stress imparted thereto. The creation of the compression residual stress may cause a portion of the inner surface of the main pipe rail surrounding the branch hole to assume a non-cylindrical configuration.

Abstract: 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.

Abstract: A joint structure for a branch connector in a common rail, comprising: a main pipe rail having a conduit therein on its axis and a plurality of through holes formed in its circumferential wall at an axial spacing, each of the through holes having a pressure receiving seat formed on the circumferential face thereof and opened to the outside; a branch connector having a conduit to communicate with the conduit of the main pipe rail and including a joint head formed at the end thereof and forming a pressure seat so that the branch connector is engaged with the main pipe rail by bringing the pressure seat thereof into abutment against the pressure receiving seat of the main pipe rail; a joint fitting mounted on the main pipe rail; and a nut assembled in advance in the branch connector and fastened into the joint fitting against the pressure of the joint head thereby to joint the branch connector to the main pipe.

Abstract: A composite metal tubing is provided which includes an inner tubular member press fitted into the bore of an outer tubular member. The inner tubular member is made of a steel having a tensile strength of at least 48 kg/mm.sup.2. Additionally, the wall of the inner tubular member has a thickness equal to 1.5 to 8.5% of the outer diameter of the outer tubular member. The resultant composite tubing has increased pressure resistance and resists cavitation.