BALANCER MECHANISM FOR IN-LINE THREE CYLINDER ENGINE

PROBLEM TO BE SOLVED: To provide a balancer mechanism for an in-line three cylinder engine capable of suppressing or decreasing that a residual pitching moment of a secondary component increases more than ever before by adopting an offset crank. SOLUTION: Crank arms 12 of respective cylinders are arranged sequentially at 120 degrees to a crank journal 11 of a crankshaft 10 and serve as the offset crank. Crank weights 21, 22, and 23 are provided at the crank arms 12 of the respective cylinders. Balance weights 25 and 26 are provided to a single balance shaft 24 that is parallel to the crank journal 11 and rotates in an opposite direction to the crank journal 11 at an equal speed. Based on a reference phase that cancels a synthesized inertial couple of force generated in the crankshaft 10 when the offset crank is not adopted, the balance weights 25 and 26 retard only by the same predetermined angle α respectively to a first cylinder side and a third cylinder side with respect to a second cylinder. COPYRIGHT: (C)2010,JPO&INPIT