| 摘要 |
PURPOSE:To simplify a device, and also to obtain it at a low cost, by clamping a mold with a bolt, and executing relief and synchronization by only a pressure-reducing valve and a diverting valve. CONSTITUTION:When a pump 32 is driven and a changeover valve 31 is switched to an upper position 31a, a part of pressurized oil is supplied to a diverting valve 27 from a main circuit 28, and the remaining portion is discharged to a supply side circuit 24. The discharge pressurized oil supplied to the diverting valve 27 pushes pistons 13, 13 into the center position. On the other hand, the pressurized oil discharged to the supply side circuit 24 is supplied to a pressure-reducing valve 25 through a check valve 26, is reduced, and led into a base material pipe 12 from a hollow pipe 14. When a relief valve 37 is reduced little by little and bulge pressure P2 is raised, the base material pipe 12 bulges along the shape of a straight surface 9a and a tapered surface 9b in a space 9, and also the upper and lower parts are compressed uniformly in the axial direction. In this case, the pistons 13, 13 synchronize and move, following in the axial direction, and at the point of time when the pistons 13, 13 have hit against the stopper, a bulge working job ends. |
