INTERNAL COMBUSTION ENGINE

摘要

PROBLEM TO BE SOLVED: To provide an internal combustion engine that has a small occupied volume to arrange a primary balancer and a secondary balancer and can be manufactured inexpensively.SOLUTION: In an internal combustion engine 1, a rotating shaft 10A of a primary balancer 10 is arranged in parallel with a rotating axis 30A of a crankshaft 30. A rotating shaft 21A of a first secondary balancer 21 is arranged coaxially with the rotating shaft 10A of the primary balancer 10. A rotating shaft 22A of a second secondary balancer 22 is arranged in parallel with the rotating shaft 21A of the first secondary balancer 21. A primary gear mechanism 40 rotates the primary balancer 10 at the same speed as rotating speed of the crankshaft 30. In a secondary gear mechanism 50, a first secondary weight 211 and a second secondary weight 221 are integrally arranged in two gears out of gears for rotating the first secondary balancer 21 and the second secondary balancer 22.