To provide a twister capable of improving productivity of a crankshaft material and eliminating problems of oil leakage, noise, etc., and a shaping method.
The twister is equipped with a twisting die 10 which houses the crankshaft material, upper and lower movable retainers 13, 14 which hold the twisting die 10, and exert a twist shaping force to the crankshaft material by rotating the die, a twisting beam mechanism which rotates the upper and lower movable retainers 13, 14 by ascending and descending, and a drive unit which drives the twisting beam mechanism to ascend and descend. The drive unit comprises a screw and nut mechanism consisting of a screw rod 22 rotated by a servo motor 21 and a nut 23 screwed to the screw rod 22 and fixed to the twisting beam mechanism. The moving strokes of the nut 23 of the drive unit are detected by the integrated number of revolutions of the servo motor 21 and the driving speed is lowered just before the target position where the twist shaping angle is attained. The driving is then stopped in the target position.
Hiroshi Nakai
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