| 摘要 |
PROBLEM TO BE SOLVED: To precisely detect contact of an upper die with a work even in the case of a bending apparatus using a cylinder mechanism as a drive source of an elevating drive mechanism. SOLUTION: The elevating drive mechanism 20 of the upper die includes a hydraulic cylinder 21, hydraulic circuit 50, pump 30 and servomotor 40. When the upper die is in descending operation, the work is bent by a bending angle corresponding to a pressing-in quantity into a groove of a lower die by applying press force due to the upper die to the work. An elevated position of the upper die is detected by a position detector 14. A controller 70, in a state in which the upper die is controlled so as to descend by the gravity, fetches the elevation position of the upper die from the position detector 14 as a contact position of the upper die with the work when the difference between a position command value and an elevation position of the upper die detected by the position detector 14 reaches a prescribed threshold value, a descending end position of the upper die is obtained by adding a pressing-in quantity thereto.
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