Three dimensional cam, grinding method and grinding apparatus
AssigneeYamaha Hatsudoki Kabushiki Kaisha
InventorsYuji Saiki, Naoki Tsuchida, Mitsuo Tsuchiya
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Abstract
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.
Claims12
A three-dimensional cam rotatable about a cam axis for operating a cam follower pivotal about an axis disposed obliquely to said cam axis, said three dimensional cam having an operating face formed with a series of regularly arranged recesses.
A grinding machine for grinding a three-dimensional slightly concave cam surface, said grinding machine comprising a grinding wheel having a rotational axis and a grinding surface formed by a convex curved surface having a radius of curvature smaller than the concave cam surface of the cam, a grinding wheel drive rotating said grinding wheel about its rotational axis and grinding means for translating the rotational axis of said grinding wheel based on a target cam profile and a target shape of the cam surface face set for each given rotation angle of the cam, said grinding means being adapted to grind the cam surface along a grinding point that is moved in the rotational and axial directions while maintaining a normal vector of said grinding wheel in coincidence with a normal vector of the desired cam surface.
A method of grinding a three-dimensional slightly concave cam surface utilizing a grinding wheel having a rotational axis and a grinding surface formed by a convex curved surface having a radius of curvature smaller than the concave cam surface of the cam, said method comprising the steps of rotating the grinding wheel about its rotational axis and translating the rotational axis of the grinding wheel based on a target cam profile and a target shape of the cam surface face set for each given rotation angle of the cam by grinding the cam surface along a grinding point that is moved in the rotational and axial directions while maintaining a normal vector of the grinding wheel in coincidence with a normal vector of the desired cam surface.
Dependencies are inferred from the claim text.