Internal combustion engine with mass balance

摘要

An internal combustion engine provided with a mass balance unit of the second order. The mass balance unit includes two balancing shafts with each of the balancing shafts being provided with balancing weights. The balancing shafts are arranged on respective sides of the crankshaft of the engine and extend in parallel thereto. The balancing shafts are driven with a chain by a sprocket wheel seated on the crankshaft with one of the shafts being directly driven for rotation in the direction of rotation of the crankshaft and the other rotating, through the interposition of a pair of gear wheels, in a direction in opposition to the direction of rotation of the crankshaft. The directly driven balancing shaft with sprocket wheel is mounted on an inside of the lid covering an opening of the crankcase of the engine. The other balancing shaft is supported on a bearing cover for the crankshaft and the driving is effected from a sprocket wheel attached to a crank web of the crankshaft.