| 摘要 |
PROBLEM TO BE SOLVED: To provide a manufacturing method and a manufacturing device for a long size shaft, by which it can be manufactured inexpensively and with high precision. SOLUTION: In a manufacturing device for a long size shaft, the hole diameter d1 of the stock feeding port 18 of a die 19 is made larger than the outside diameter d2 of a stock 16. Further, oil clearance grooves 26 having oil clearance holes positioning on the tip side from about the half of the whole length of the stock 16 in the shaft 20 direction and communicating with a gap (t'), are provided on a die 19. Also, in the manufacturing method of the long size shaft, a lubricating film 27 is relieved through the oil clearance grooves 26 during extrusion and a surface finish is performed by removing with centerless working after extrusion respective swelled parts 28 formed on the rear end side of the long size shaft 22 and in parts where the oil clearance grooves 26 position.
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