| 摘要 |
PROBLEM TO BE SOLVED: To optimize a shape of a rocker arm constituting a piston-crank mechanism.SOLUTION: When viewed in a crank shaft axis direction, a straight line passing the second interlocking pin center 16a and the crank pin center 5a is defined as a straight line L1, a straight line passing the sway fulcrum 7 and orthogonal to the straight line L1 a straight line L2, a straight line parallel to the straight line L2 and passing the second interlocking pin center 16a a straight line L3, and a circle coaxial with the sway supporting shaft 13 with its inside region occupied with the rocker arm 10 or the sway supporting shaft 13 a reference imaginary circle C. When the rocker arm 10 is formed so that a reference imaginary circle C1 is provided as the settable maximum value in a region with the radius of the reference imaginary circle C between the straight line L2 and the straight line L3 at the bottom dead center, the intersection A of the straight line L1 and the straight line L2 is included in the reference imaginary circle C1, and the rocker arm 10 is present between the second interlocking pin center 16a and the intersection A on the straight line L1. |
