| 摘要 |
In a crankshaft of an internal combustion engine wherein a crankthrow is shortened by the use of a multi-link mechanism, a stress concentration caused by a torsional torque in the vicinity of a pin-side opening (21) of an oil passage (20), which is open at the outer peripheral surface of a crankpin, is alleviated. The crankthrow from the axis of a main journal (2) to the axis of the crankpin (3) is set shorter than one-half of a piston stroke. The oil passage (20) is formed to supply lubricating oil to a bearing portion of the crankpin (3). The pin-side opening (21) of the oil passage (20), which is open at the outer peripheral surface of the crankpin (3), is formed in ranges other than angular ranges of 0°, 90°, 180°, and 270° with respect to a reference line (X1) extending from the axis of the main journal (2) toward the axis of the crankpin (3) in a decentering direction (X) of the crankpin. |
