| 摘要 |
PROBLEM TO BE SOLVED: To suppress grinding process to the minimum, and improve work accuracy of a nozzle with a good efficiency by forming a circular cone shaped recessed part facing off against a movable valve from a plurality of surfaces of two or more stages, and differing an angle of a surface having at least a seal function of the movable valve from an angle of a surface faced to an orifice inlet part. SOLUTION: In the case where a fuel injection valve is manufactured, firstly, a seat 1b is pressed in along a cylindrical part 13a of a nozzle raw material 13, and is transferred and molded by a mold punch 14. In this time, a dice 15 is put on a lower surface 13b of the nozzle raw material 13. Then, a plastic fluid protrusion part 13c pushed out to a bottom lower surface of the nozzle raw material 13 is mechanically worked and eliminated. An orifice is worked by a punch 17 serving the seat part 1b as a guide of a punch guide 16. After that, the nozzle raw material 13 is hardened, and the cylindrical part 13a and the seat 1b are simultaneously worked by a grinding wheel having an angleθ' larger than a holding angleθof the seat 1b. It is thus possible to improve a work accuracy without reducing productivity by plastic work.
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