Engine with a balancer mechanism

An engine with a balancer mechanism, comprising

• a crank mechanism comprising a crankshaft,
• a balancer mechanism comprising a balancer shaft, and
• wherein a primary inertial force generated by rotation of the crankshaft includes a rotating component that is constant in magnitude and rotates, and a translating component that is constant in direction and varied in magnitude as the crankshaft rotates, and
• an acceleration caused by a couple of forces, which the rotating component of the primary inertial force generated by rotation of the crankshaft balances an inertial force generated by rotation of the balancer shaft to generate, and an acceleration caused by the translating component of the primary inertial force of the crankshaft are mutually put substantially in opposite directions and have substantially the same magnitude in a predetermined target position.

An engine with a balancer mechanism, comprising

• a crank mechanism,
• a balancer mechanism that inhibits vibrations caused by the crank mechanism, and
• wherein an instantaneous center of rotation of the engine is arranged in the neighborhood of a predetermined target position by adjusting an acceleration caused by a translational force generated by a primary inertial force of the crank mechanism and an inertial force of the balancer mechanism and an acceleration caused by a couple of forces generated by the primary inertial force of the crank mechanism and the inertial force of the balancer mechanism, and
• a vibration proof member is provided to lessen transmission of vibrations, which are caused by a secondary inertial force of the crank mechanism, outside of the target position.