| 摘要 |
PURPOSE:To form a high quality annular product having uniform thickness over whole circumference by lowering pressing force of a rolling reduction roll after thickness of rolled annular material arrives at a specified value, and continueing roll forming for a specified time. CONSTITUTION:An annular material W is roll formed by a die 18 that is rotated in the direction of arrow (e) in the die head 2 by driving of a motor (omitted in the figure) and a rolling reduction roll 13 to which forming pressure is given by operation of pressing down cylinder through a rod 15, a spindle case 10 etc. When the material W attain specified thickness, this is detected by a detector 44 and a detection signal is outputted. A control box 48 gives a controlling signal to control changeover switches 32, 40, 42 etc., and rolling reduction of the roll 13 is stopped. At the same time, the die 18 and rolling reduction roll 13 are continued to rotate for a specified time at pressing force which is not large enough to cause plastic deformation to the material W, and inner diameter of the material W is made even. |
