To decrease an input load to a cylinder block.
A piston-crank mechanism of an internal combustion engine includes: a rocker arm 10 that rocks around a rocking support shaft; a first link 11 connecting one end of the rocker arm 10 with the piston; and a second link 12 connecting the other end of the rocker arm 10 with a crank pin of a crankshaft. At a crank angle where an included angle by the rocker arm 10 and the second link 12 is minimum, when a straight line passing a rocking fulcrum 7 being the center of the rocking support shaft and parallel to the second link 12 is denoted as a first straight line A1, the gravity center position G of the rocker arm 10 is set, in a view along the crankshaft axis, to an opposite side to the piston across the first straight line A1.
IDE EMI
MOGI KATSUYA
Tomioka Kiyoshi
Tsuyoshi Hashimoto