Toyota Jidosha Kabushiki Kaisha

Sumitomo Electric Industries, Limited

Toyota Motor Corporation

Koji Kazuoka

Tetsuya Suganuma

Yoshitaka Takahashi

Shuichi Fujita

Nobuhito Kuroishi

Katsuhiko Ueda

Hitoshi Nakamura

Naoki Motooka

Testuya Suganuma

Takeshi Okujo

A valve-seat insert for internal combustion engines comprises a double layered, sintered alloy composed of a valve-seat layer on which a valve is seated, and a base layer integrated with the valve-seat layer and adapted to be seated in a cylinder head of an engine. The valve-seat layer is composed of a sintered alloy of a high heat resistance and a high wear resistance having a composition comprising, by weight, 4 to 8% Co, 0.6 to 1.6% Cr, 4 to 8% Mo, 1 to 3% Ni, 0.3 to 1.5% C, 0.2 to 0.6% Ca, and the balance being substantially Fe, the additives, Co, Cr and Mo being present mainly in a form of a Co-Cr-Mo hard alloy and a hard Fe-Mo alloy dispersed in the Fe matrix. The base layer is composed of a sintered alloy of a higher heat resistance and a higher wear resistance than those of the valve-seat layer and having a composition comprising, by weight, 11 to 15% Cr, 0.4 to 2.0% Mo, 0.05 to 0.3% C, balance substantially Fe. The sintered alloy for the base layer may have a compositions further including 2 to 4% Cu.

Valve-seat insert for internal combustion engines

A method for manufacturing a firm and rigid cam-cam shaft assembly, which comprises the steps: (a) molding a component having through-hole therein from a material of an alloy to be sintered, said material allowing the first ratio of the contraction of the inner diameter of the component at joining portion when the component is singly sintered to the inner diameter thereof before sintering to be more than 2%; (b) presintering said component; (c) assembling said component onto a metal shaft such that said metal shaft may be inserted into said through-hole; and (d) sintering said component assembled onto the metal shaft, whereby the joining of the component to the metal shaft is carried out in such a manner that the second ratio of the difference between the outer diameter of the metal shaft and the inner diameter of the contracted component after sintering to the outer diameter of the metal shaft is more than 2%.

Method for manufacturing a cam-cam shaft assembly

A method for manufacturing a slide member by molding an alloy powder composed of, by weight, from 2.5 to 7.5% of Cr, from 0.1 to 3.0% of Mn, from 0.2 to 0.8% of P, from 1.0 to 5.0% of Cu, from 0.5 to 2.0% of Si, from 0 to 3% of Mo, from 1.5 to 3.5% of C, and the balance being Fe with less than 2.0% of impurities into a compressed powder mass under a molding product pressure of 5 to 7 ton/cm.sup.2 ; sintering the compressed powder mass at a temperature of 1020.degree. to 1180.degree. C. to produce a sintered alloy mass; treating the sintered alloy mass for 0.5 to 3 hours by soaking the sintered alloy mass at a temperature from 450.degree. to 550.degree. C. under a reduced pressure of 0.1 to 0.8 atm. while exposing the sintered alloy mass to a gas, the gas having a main component selected from the group consisting of a non-oxidizing type gas and an endothermic type gas, and containing 20 to 40 vol. % of heated steam; and forming a film of tri-iron tetroxide on a surface of the sintered mass and on wall portions of a plurality of pores formed within the sintered mass.

Method for manufacturing a slide member

An anti-wear sintered alloy comprising from 2.5 to 25.0% of Cr, from 0.10 to 3.0% of Mn, from 0.1 to 0.8% of P, from 1.0 to 5.0% of Cu, from 0.5 to 2.0% of Si, from 0 to 3% of Mo, 1.5 to 3.5% of C, one selected from the group consisting of from 0.5 to 3.0% of S and from 1.0 to 5.0% of Pb, and the balance being Fe with less than 2% of impurities, wherein S or Pb is distributed uniformly in the sintered alloy in form of sulfide or lead particle of less than 100 .mu.m and a manufacturing process thereof.

Anti-wear sintered alloy and manufacturing process thereof

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Toyota, Japan

Koji Kazuoka