Nippon Piston Ring Co., Ltd.

Nissan Motor Company Limited

Honda Giken Kogyo Kabushiki Kaisha

Osamu Kawamura

Teruo Takahashi

Yoshikatsu Nakamura

Arata Kakiuchi

Makoto Kano

Tsutomu Saka

Shigeo Murata

Katsuaki Sato

Ichiro Tanimoto

Katsuhiko Tominaga

Shinichi Yamamoto

Takeshi Hiraoka

Hiroshi Oshige

Toshiaki Sato

Takao Omiya

Takashi Kawamoto

Souichi Shimomura

A sintered Fe alloy for a valve seat is made of a prepared powdery alloy which comprises C of from 0.3 wt. % to 1.6 wt. %, Cu of from 5 wt. % to 20 wt. %, hard particle of from 5 wt. % to 40 wt. % which consists of at least one species selected from ferroalloy, ceramic and intermetallic compound, and a balance which is a powdery Fe atomizing alloy containing at least one species of from 1 wt. % to 8 wt. % selected from Cr and Mo. The prepared powdery alloy containing the above-mentioned component and content is subject to a press forming process by a compression molding to form a green compact body which is then sintered. The sintered Fe alloy has a high thermal conductivity, a high strength at a high temperature and an excellent abrasion resistance, and, moreover, can be used for a valve seat provided in a high function engine.

Sintered Fe alloy for valve seat

The invention is directed to a joined type valve seat which is joined into the cylinder head of an aluminum alloy in an internal combustion engine by resistance welding and, in particular, to an improved joined type valve seat superior in strength, rigidity, and abrasion resistance, whereby no cracks are caused when running the engine or when joining the valve seat to the engine block by resistance welding. The valve seat is made of a material having a tensile strength of 300 MPa or above, a radial crushing strength of 500 MPa or above, an elongation of 0.6% or more, a thermal conductivity of 15 W/(m.multidot.K) or above, a coefficient of thermal expansion of 10.times.10-.sup.6 (1/K) or above, and an electric resistivity of 50 .mu..OMEGA..multidot.cm or below.

Joined type valve seat

A camshaft made of cast iron containing at least one element selected from the group consisting of Bi, Te, Se, As, Sb and Sn in a total amount of 0.0001 to 0.1 weight %, preferably, 0.001 to 0.1 weight %. The cast iron may further contain at least one elements selected from the group consisting of Ni, Cu and Co in an amount of 0.2 to 5.0 weight %. Furthermore, in the camshaft of the present invention, a carbide area ratio at the sliding surface of the cam lobe portion is not less than 40%, the chilled carbide has an average grain diameter of not more than 15 .mu.m, and the sliding surface of the cam lobe portion has a hardness of not less than HRC 53.

Method of manufacturing a camshaft

A camshaft made of cast iron containing at least one element selected from the group consisting of Bi, Te, Se, As, Sb and Sn in a total amount of 0.0001 to 0.1 weight %, preferably, 0.001 to 0.1 weight %. The cast iron may further contain at least one element selected from the group consisting of Ni, Cu and Co, in an amount of 0.2 to 5.0 weight %. Furthermore, in the camshaft of the present invention, a carbide area ratio at the sliding surface of the cam lobe portion is not less than 40%, the chilled carbide has an average grain diameter of not more than 15 .mu.m, and the sliding surface of the cam lobe portion has a hardness of not less than HRC 53.

Camshaft

A secondary hardening type high temperature wear-resistant sintered alloy body comprising 0.4 to 15 wt. % of at least one species of metal carbide forming element which is selected from the group consisting of W, Mo, V, Ti, Nb, Ta and B; 5 to 35 wt. % of at least one species of austenite forming element which is selected from the group consisting of Ni, Co, Cu, and Cr; 0.2 to 1.2 wt. % of C; and 0.04 to 0.2 wt. % of Al consisting essentially the remainder of Fe, wherein the alloy body contains an austenite phase which is capable of martensitic transformation.

Valve seat made of secondary hardening-type high temperature

A synchronizer ring having a stabilized friction characteristic relative to a taper cone and having sufficient mechanical strength and anti-abrasion characteristic. The synchronizer ring is made from a ferrous sintered alloy containing 0.2 to 1.0% by weight of carbon, 8.0 to 15.0% by weight of copper, 0.1 to 7.0% by weight of at least one component selected from a group consisting of chromium, manganese, molybdenum, and phosphorus, and balance iron and inevitable impurities. A free copper is precipitated in a matrix of the sintered alloy. Porosity of the sintered alloy is from 3 to 8 vol %.

Synchronizer ring

A synchronizer ring for performing synchronous sliding operation with and separating operation from a rotating object member, comprises a ring body having a sliding surface slidable in contact with the object member and a copper alloy flame-coated film formed on the sliding surface. The copper alloy flame-coated film has a Zn equivalent of 40 to 65, a surface porosity of 5 to 30 volume % and a thickness of 70 to 200 .mu.m. The copper alloy flame-coated film also may have a surface roughness (Rz) of 20 to 60 .mu.m, and a ceramic content of 5 to 30 weight %.

A secondary hardening type high temperature wear-resistant sintered alloy body comprising 0.4 to 15 wt. % of at least one species of metal carbide forming element which is selected from the group consisting of W, Mo, V, Ti, Nb, Ta and B; 5 to 35 wt. % of at least one species of austenite forming element which is selected from the group consisting of Ni, Co, Cu, and Cr; 0.2 to 1.2 wt. % of C; and 0.04 to 0.2 wt % of the remainder consisting essentially of Fe wherein the alloy body contains an austenite phase which is capable of martensitic transformation.

Secondary hardening type high temperature wear-resistant sintered alloy

A synchronizer ring for performing synchronous sliding operation with and separating operation from a rotating object member, comprises a ring body having a sliding surface in slidable contact with the object member and a molybdenum or molybdenum alloy flame-coated film formed on the sliding surface, the film having a ceramic present in an amount of 5 to 30 weight %. The flame-coated film may have a surface roughness (Rz) of 20 to 60 .mu.m. The flame-coated film may further have a surface porosity of 5 to 30%, preferably 7 to 25% and a film thickness of 70 to 200 .mu.m, preferably 90 to 120 .mu.m.

In a process of casting a rocker arm as one piece from high chrome cast iron, a Ca-Si base addition agent is added to the molten metal in an amount of 0.3 to 0.6% by weight. The agent is effective as a globulizer to round high-hardness carbide precipitates directing toward the casting surface.

Rocker arm and method of casting

A high strength high chromium cast iron contains fine particle precipitated hard carbide. The precipitated hard carbide has an average particle size of 20 .mu.m or less and hardness of Hv 500 or more in martensite base matrix, and has area ratio in a range of 30% or more and 45% or less. The precipitated hard carbide has spheroidal ratio (surface area of sphere circumscribing the precipitated hard carbide versus actual surface area of precipitated hard carbide) of 40% or more.

High strength high chromium cast iron and valve rocker arm made thereof

A rocker arm for use in an internal combustion engine. The rocker arm has a portion abutting an opponent mechanical component, and at least the portion is formed of a cast iron consisting of from 2.5 to 3.7 wt % of carbon; from 1.0 to 2.0 wt % of silicon; from 0.5 to 1.0 wt % of manganese; from 10 to 20 wt % of chromium; from 0.3 to 0.7 wt % of nickel; not more than 0.3 wt % of phosphorus; not more than 0.1 wt % of sulfur; and balance iron and impurities; Carbide mainly containing chromium is uniformly precipitated from at least one of pearlitic and martensitic matrix in the cast iron.

Rocker arm having wear resistant scuffing resistant portion

A sliding member for use in an internal combustion engine having an improved wear resistance. The sliding member has a sliding surface composed of a mixture of 50 to 97% by weight of high carbon ferrochromium and 3 to 50% by weight of ferrous alloy applied thereto by spraying. In a preferred embodiment, the ferrous alloy is high carbon iron containing at least 0.6% by weight of carbon.

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Shimotsuga, Japan

Osamu Kawamura