| 摘要 |
PURPOSE:To largely reduce the weight by reducing the number of counterweights fitted to a crank shaft to the minimum. CONSTITUTION:No counterweight is provided on the 3rd, 4th, 6th, 7th arms 33, 34, 36, 37. Counterweights 61, 69 with the same shape, same weight, same section modulus are provided on the 1st and 9th arms 31, 39 so that the balance is kept by only both counterweights. The 2nd, 5th, 8th arms 32, 35, 38 are arranged line- symmetrically against the arm 35 apart by 120 deg. in the circumferential direction, and counter weights 62, 65, 68 with the same weight, same shape, same section modulus are provided on them so that the balance is kept by only these counterweights. |
