| 摘要 |
PURPOSE:To restrain vibration of an engine and an increase in local stress of a crankshaft moving portion by removing unbalanced inertia force and couple of forces of the whole crankshaft, and simultaneously eliminating the partial unbalanced condition. CONSTITUTION:A crankshaft 10 is supported at the first main bearing portion 12, the second main bearing portion 14, the third main bearing portion 16 and the fourth main bearing portion 18 in order from the front. The forward end first crankarm 32 and the trailing end ninth crankarm 48 are provided with the first counterweights 32a, 48a disposed opposite to adjacent crankpins 20, 30. The second counterweights 36a, 38a, 42a, 44a are disposed at the end portions of crankarms 36, 38, 42, 44 on both front and rear sides of the second and third main bearings 14, 16 fron the front. The second counterweights are located at positions turned in a 180 deg. arc from the array direction of the corresponding adjacent crank pins. |
