| US 7,500,472 B2 | ||
| Fuel injection valve | ||
| Takahiro Hamada, Yokohama (Japan); Yutaka Mabuchi, Yokohama (Japan); Makoto Kano, Yokohama (Japan); and Yuuji Azuma, Yokohama (Japan) | ||
| Assigned to Nissan Motor Co., Ltd., Yokohama-shi (Japan) | ||
| Filed on Apr. 14, 2004, as Appl. No. 10/823,773. | ||
| Claims priority of application No. 2003-110398 (JP), filed on Apr. 15, 2003. | ||
| Prior Publication US 2005/0035222 A1, Feb. 17, 2005 | ||
| Int. Cl. F02M 59/46 (2006.01); F02M 59/48 (2006.01) | ||
| U.S. Cl. 123—467 [239/533.11; 239/591] | 7 Claims |
| 1. A fuel injection valve comprising:
a needle valve including a base material;
an opposite member including a base material whose sliding section is in slidable contact with a sliding section of the base
material of the needle valve in presence of fuel for an automotive vehicle; and
a hard carbon thin film coated on at least one of the sliding sections of the base materials of the needle valve and the opposite
member, the hard carbon thin film having a surface hardness ranging from 1500 to 4500 kg/mm2 in Knoop hardness, a film thickness ranging from 0.3 to 2.0 μm, and a surface roughness (Ry) (μm) which satisfies a relationship
represented by the following formula (A):
Ry <(0.75−Hk/8000)×h +0.0875 (A)
where h is the thickness (μm) of the hard carbon thin film; and Hk is the surface hardness in Knoop hardness (kg/mm2) of the hard carbon thin film.
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