| 摘要 |
PROBLEM TO BE SOLVED: To provide a lubricating structure of internal-combustion engines that can prevent abrasion or wear of end-side connecting rod bearings and thus suppress vibration and noise without causing increases in weight and in friction loss. SOLUTION: An end-side crank journal 21a has an internal oil hole 27. Another oil hole 28 opens at one end onto one end of the oil hole 27 and at the other end onto the periphery of a crankpin 23. An end-side journal bearing 24a has an arcuately sectioned groove 29 cut along the internal surface of an upper bearing part 24U to open on an oil feed passage 25. The oil feed passage 25, oil holes 27 and 28 and groove 29 cooperate to feed lubricating oil to an end-side connecting rod bearing 26a without interruption. An intermittent lubricating means consists of the oil feed passage 25, and an oil hole passing through the crank arm that exists between a crank journal other than such end-side ones and the crankpin 23.
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