| 摘要 |
PURPOSE: A crank shaft of a multi-cylinder engine is provided to apply weight to balance weights of crank arms based on the minimum distance capable of preventing the interference when the crank shaft is rotated, thereby solving a problem of the unbalance of the inertia or the torque while preventing the interference with a peripheral portion. CONSTITUTION: A crank shaft of a multi-cylinder engine includes three pairs of crank arms (1-1, 1-2, 1-3). The crank arm pairs face each other while interposing a crank pin and are arranged to be radically dislocated at a predetermined angle on the crank shaft. Balance weights are formed to be integrated on the first and third crank arms arranged on the outer side of the crank shaft. The balance weights have asymmetric cross sectional structure having the biased center of gravity, and a shape of the balance weight is limited by two circles (12, 14) having different center. |
