FUEL INJECTOR REDUCING STRESS CONCENTRATION

摘要

On an inner wall of a bag-shaped hole portion (45C) of a nozzle body (48), a cross angle between the bag-shaped hole portion (45C) and a needle hole (45) or an oblique high-pressure fuel passage (46) of the nozzle body (48) is made obtuse, i.e. at 90 degrees or larger, through an electrochemical machining process with a suitably-shaped electrode (G) or through after-processing with a boring tool (H) having a predetermined shape. The center of the bag-shaped hole portion (45C) may be deviated toward the high-pressure fuel passage (46) or the high-pressure fuel passage (46) may be connected to a maximum diameter portion of the bag-shaped hole portion (45C) to provide the obtuse cross angle. Thus, excessive stress on the inner wall of the bag-shaped hole portion (45C) or a breakage of the nozzle body (48) due to a crack can be inhibited.