Link type variable stroke engine

A link type variable stroke engine in which

• a crankshaft and a rotary shaft are each rotatably supported on a case main body and a support plate, the case main body formed integrally with a cylinder block and opened at one side to form a part of a crankcase, the support plate fastened to an opened end of the case main body at a plurality of positions, the rotary shaft having an axis parallel with the crankshaft and being provided with an eccentric shaft at an eccentric position,
• a piston slidably fitted to the cylinder block, the crankshaft and the eccentric shaft are linked by a linking mechanism, and
• the linking mechanism includes:
• a main connecting rod coupled, at one end, with the piston;
• a sub connecting rod rotatably coupled with a crank pin of the crankshaft and rotatably coupled with the other end of the main connecting rod;
• and a swing rod rotatably coupled, at one end;
• with the sub connecting rod at a position displaced from a position coupled with the main connecting rod and rotatably coupled, at the other end, with the eccentric shaft,
• wherein, in a projection view on a plane orthogonal to an axis of the crankshaft and the axis of the rotary shaft, two of the plurality of fastening positions at which the support plate is fastened to the opened end of the case main body are disposed on a straight line passing the axes of the rotary shaft and the crankshaft.