| 摘要 |
PURPOSE:To increase the inertia moment of a balancer by making the outer peripheral shape of the balancer of a crankshaft close to the envelope plane of the under surface of a piston around a crank pin through a connecting rod. CONSTITUTION:The shortest distance S from the center point Q of the piston pin 8 of a piston 3 at the bottom dead center position to the outer peripheral surface of a balancer 7 is obtained. Said distance S is the length which is obtained by adding the clearance 8 up to the outer peripheral surface of the balancer 7 from the under-surface of the piston 3 to the distance to the piston 3 under-surface from the center point Q. Then, the envelope plane as the locus of the point departing by the distance S from the center point Q of the piston pin 8 in the case when the piston 3 moves is obtained. Said envelope plane is used as the outer peripheral shape of the balancer 7. Therefore, the outer peripheral part of the balancer 7 can be spread without varying the length of a connecting rod 4, namely without increasing the whole height of the engine. Therefore, the inertia moment of the balancer 7 can be increased. |
