Balance shaft supporting structure in engine

摘要

A secondary balancer device provided below a cylinder block (4) of an engine including a front balancer shaft (21) and a rear balancer shaft (22) which are rotated in opposite directions and have longitudinally central main journal portions (26) carried in a balancer holder (29), respectively. Bracing journal portions (26) are provided on axial ends of one of the front and rear balancer shafts (21,22) and supported in a pump body (11) and a pump cover (12) of an oil pump (7) provided below the cylinder block, respectively. A pump shaft of the oil pump (7) and the front balancer shaft (21) are connected to a crankshaft (1) by a common endless chain (36) and rotated at different numbers of revolutions. Thus, the number of parts for supporting the balancer shafts (21,22) can be reduced, while maintaining the freedom of setting the number of revolutions of the oil pump (7) of the engine.