Yamaha Hatsudoki Kabushiki Kaisha

Mitsuo Tsuchiya

Naoki Tsuchida

Yuji Saiki

An improved cam and follower arrangement suitable for actuating, for example, poppet valves of an internal combustion engine and method and apparatus for forming the cam surface. This permits the use of skewed valve axes without using multiple rocker arms for each valve. The shapes are chosen and formed to provide better contact area and permits the cams to be ground with conventional grinding methods and for multi-cylinder engines.

Three dimensional cam, grinding method and grinding apparatus

A multi-valve internal combustion engine having a plurality of valves having skewed axes that are operated by cam lobes of a single cam shaft. The cam shaft operates the valves through rocker arms each of which are pivoted independently about axes that are skewed relative to the cam shaft axis so as to minimize bending stresses on the valve during its actuation. This also avoids scuffing between the rocker and the valve stem. At the same time, good contact is maintained between the cam lobe and the follower surface by machining the cam lobe so that it will have a slight concavity at least in its tip portion so as to ensure constant line contact with the follower.

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Iwata, Japan

Mitsuo Tsuchiya