| 摘要 |
PROBLEM TO BE SOLVED: To provide a method of manufacturing a hollow crank shaft improved in strength and dimensional accuracy, while reducing weight and forming an oil path, and to provide a hollow crank shaft. SOLUTION: In this method of manufacturing a hollow crank shaft arranged in an internal combustion engine, a crank shaft forging is manufactured by forging a crank shaft raw material workpiece 28 of double-layers structure formed of a crank shaft raw material 21 having a hollow part 17 and a core raw material 22 embedded in the hollow part 17, and thereafter, the core raw material 22 in the crank shaft forging is eliminated by using a high-temperature dissolving method. COPYRIGHT: (C)2009,JPO&INPIT
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