| 摘要 |
PROBLEM TO BE SOLVED: To provide a crank shaft of a reciprocal engine capable of dramatically reducing its weight.SOLUTION: A crank shaft includes a journal part J as a rotation center shaft, a pin part P eccentric to the journal part J, a crank arm part A connecting the journal part J and the pin part P, and a fan-shaped counter weight part W provided integrally with the arm part A. On the surface of the weight part W on the side of the journal part J, a projection part is provided at both end parts of an outer peripheral edge, and the projection parts Oj project in a shaft direction beyond the position of a journal thrust surface Jt.SELECTED DRAWING: Figure 14 |
