| 摘要 |
PROBLEM TO BE SOLVED: To improve sealing performance/abrasion resistance of a needle valve while securing cost performance of the needle valve formed of a sintered metallic material. SOLUTION: A needle valve 16 and a movable iron core 24 of a fuel injection valve are integrally molded by raw materials of different sintered metallic materials, and are simultaneously sintered. The movable iron core 24 is molded/ sintered by using magnetic metallic powder, the needle valve 16 is molded/ sintered by using nonmagnetic metallic powder, and among the needle valve 16, a part except for a seal part 21 uses metallic powder having the relatively large average particle size (for example, the average particle size of 10μm), and the seal part 21 uses metallic powder having the average particle size (for example, the average particle size not more than 7μm, desirably, not more than 5μm) smaller than the othert part. Thus, since a bore diameter of the seal part 21 is reduced, sealing performance/abrasion resistance of the seal part 21 can be improved. A cost can be reduced more than when forming the whole needle valve 16 by using metallic powder having the small average particle size.
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