| 摘要 |
PURPOSE:To cause accurate pressurizing to be able to set easily by causing the automation of pressure receiving member to give no change to oil pressure at press forming, while suspending the pressure receiving member from a press frame by way of a spring, and canceling its own weight of said pressure receiving member. CONSTITUTION:While suspending a pressure receiving member 3 so as to cancel its own weight by a spring 7 between the supporting rod 6 piercing a frame 1 and a top plate 1a, each oil pressure chamber 4a, 4b formed up and down of the piston 8 inserted into an oil pressure piston cylinder 4 is connected to an oil pressure source 10 by way of four directional electromagnetic switch valve 9. The oil path 18 returning to a tank 17 by way of an electromagnetic switching valve 14, an accumulator 15 and a safety valve, is connected to the oil path 11 between the four directional electromagnetic switch valve 9 and the lower oil pressure chamber 4b. When press-forming is carried out, pushing a push member to the lower surface of the pressure receiving member 3 by the oil pressure piston cylinder 4, a set load and upper limit and lower limit loads may be set at the lower surface of the cieling plate 1a by said device, thereby keeping the oil pressure constant. |
