| 摘要 |
PURPOSE:To harden a crank shaft with good dimensional accuracy by subjecting the center journal part which is not yet hardened after hardening of the journal parts, pin parts and the fillet parts thereof to roll leveling then applying the specific load and rotation to the crank shaft and hardening the respective remaining parts. CONSTITUTION:The other journal parts 101, 103, 107, 109 except the center journal part 105 among the journal parts provided on the same axial line of the crank shaft 1, pin parts 102, 104, 106, 108 and the respective fillet parts thereof are subjected to high-frequency hardening. After the shaft 1 is set to a leveling roll device 2, the journal part 105 which is not yet hardened is subjected to leveling rolling. The central part of both ends in the axial direction of the shaft 1 is thereafter supported by the clampers of a holding and hardening device 3 and the shaft 1 is rotationally driven. The shaft is pressed axially with the prescribed load by the above-mentioned clampers. The journals 103, 107 are held at the same instant while the pressing load is intermittently applied thereto in the direction perpendicular to the axial direction by blocks 305, 306 having rollers and in this state the journal part 105 and the fillet parts thereof are subjected to high-frequency hardening.
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