| 摘要 |
PROBLEM TO BE SOLVED: To solve problems, for example, in a conventional extrusion press, depressurization of a main cylinder and a side cylinder is required when finishing extrusion and stopping extrusion, but immediate depressurization causes opening of extension of a tie bar, and an end platen and a die return to a non-pressurized state, and then tension force is applied to an extrusion product in a precise product such as a heat exchange tube, resulting in deformation of the extrusion product and harmful effects.SOLUTION: Operation oil pressure releasing valves having different capacity are provided on pressurization lines of a main cylinder and a side cylinder of an extrusion press device for solving such problems. By combining discharge of the operation oil pressure releasing valves and an oil pressure pump when extrusion of a billet is finished and stopped, extraction of operation oil is performed gradually. |
