Fuji Oozx Inc.

Tohoku Steel Co., Ltd.

Shinichi Umino

Akihiro Hamada

Takeji Kenmoku

Yoshio Matsumura

Eiji Hirai

Kazuyoshi Kurosawa

Yuji Takano

Yoshitaka Nishizawa

A poppet valve in an internal combustion engine comprises a valve head and a valve stem. On a valve face of the valve head, a hardened layer of dendrites in which crystals are directed from the inside to the surface is formed, thereby increasing wear resistance of the valve face without cladding.

Poppet valve and method of manufacturing it

A steel for exhaust valves comprises C: 0.50-0.65 wt %, Si: 0.1-0.3 wt %, Mn: 5.0-8.0 wt %, Cr: 22.0-24.0 wt %, Ni: 5.0-7.0 wt %, Cu: 0.4-1.0 wt %, Mo: 0.4-2.0 wt %, W: 0.4-2.0 wt %, Nb: 0.4-2.0 wt %, Ti: 0.1-0.3 wt %, N: 0.35-0.50 wt %, sol. Al: 0.005-0.03 wt %, B: 0.001-0.01 wt %, provided that (Cu+Ni): 5.8-7.6 wt %, and the balance being Fe and inevitable impurities and has excellent high-temperature strength, corrosion resistance at room and higher temperatures and oxidation resistance.

Steels for exhaust valves having improved fatigue strength at high

A shim for a tappet is used in a valve operating mechanism in an internal combustion engine. On the surface of the shim which a cam slidably contacts, there are provided a number of bores in which lubricating oil is put. When an oil film disappears on the surface by slidable contact with the cam, oil overflows from the bores onto the surface. By increasing oil-keeping capability on the surface of the shim, frictional resistance is reduced, thereby preventing wear in the shim and the cam. The bores may be filled with a lubricating solid such as molybdenum disulfide or plastics, such as polyethylene, silicone and Teflon.RTM.. The diameter of the bores may become larger as the bores extend away from the surface of the shim, thereby preventing the solid material from being displaced from the bores. The density of the bores on the shim surface can also be varied. The density of the bores in the central area of the shim surface can be greater than in the surrounding area.

Shim for a tappet in an internal combustion engine

There is provided a new method of improving properties of the surface of an internal combustion engine valve made from titanium alloy, which comprises; the steps of (a) forming a surface undercoat layer of nickel on a surface of the engine valve; (b) heating the resulting nickel undercoated valve in vacuum or in an atmosphere of inert gas, at the temperature of 450.degree. C. to 600.degree. C., for one to four hours; (c) forming further a three component coat layer comprising nickel, phosphorus and particles of material selected from the group consisting of silicone carbide, silicone nitride, boron nitride, and the combination thereof, on the surface of the nickel undercoat layer; and (d) heating the resulting coat layer formed on the nickel undercoat layer, at the temperature of 350.degree. C. to 550.degree. C., for one to four hours, so as to make the particles of ceramic material uniformly and homogeneously dispersed in said coat layer.

Properties of the surface of a titanium alloy engine valve

There is provided a new structure of an engine valve made from titanium alloy, having three component coat surface layer formed on the surface of the reciprocating shaft thereof, wherein the composition of the three component coat surface layer comprises nickel, phospher and particles of material selected from the group consisting of silicone carbide, silicone nitride, boron nitride, and the combination thereof; said particles are uniformly dispersed in said coat surface layer; and said coat surface layer is formed via a binding layer or directly on the surface of the shaft.

Growing community of inventors

Yugawara-cho, Japan

Shinichi Umino