Patent ID: 8136501

Claim:
A variable stroke engine, comprising: a crankshaft, a camshaft constituting a part of a valve-operating system, and having an intake-side cam and an exhaust-side cam provided thereon; a rotational shaft having an eccentric shaft, wherein said crankshaft, said camshaft and said rotational shaft are rotatably supported in a crankcase of an engine body so as to have axes parallel to one another; a connecting rod connected, at one end portion thereof, to a piston by a piston pin; a control rod connected, at one end portion thereof, to said eccentric shaft; and a second end portion of said connecting rod and a second end portion of said control rod being linked to each other by a link member, rotatably supported by a crank pin of said crankshaft, wherein a rotative power of said crankshaft is transmitted to said camshaft, wherein said intake-side and exhaust-side cams are disposed at the same position of a part of said link member in a direction along an axis of said crankshaft, said camshaft and said rotational shaft are disposed on a same side with respect to a cylinder axis in a projection on a plane perpendicular to the axis of said crankshaft, a trajectory drawn by said link member on said projection plane is set so that a curved line dented toward a side opposite to said intake-side and exhaust side cams is formed at a part, of its trajectory, facing said cams, said camshaft is disposed at such a position that part of a trajectory drawn by said intake-side and exhaust-side cams overlaps said curved line of said trajectory drawn by said link member on said projection plane, and a rotational phase of said camshaft is set so that an interference, of said intake-side and exhaust-side cams with an end portion, on the camshaft side, of said link member, is avoided.