method and device for a process and device for note note an abnormality in a hydraulic system in a hydraulic system of a gussmaschine abnormality of gussmaschine

摘要

PURPOSE: To prevent a false operation and damage by a method wherein a valve for supplying a working fluid is held at a neutral position when a movable member does not operate, and an abnormality signal is outputted on the occasion when one of two pressure chambers of a hydraulic cylinder deviates from a pressure range set beforehand. ;CONSTITUTION: When a working fluid is supplied to a servo valve 7 from a pressure source 22, pressures of the working fluid supplied into two pressure chambers 5 and 6 of a hydraulic cylinder 4 from two ports A and B of the servo valve 7 rise and, after the time of a rising process passes, a balanced state is reached at a pressure being about a half of the pressure generated in the pressure source 22. At a prescribed time in the balanced state of the pressure till a start of injection, pressures detected by pressure sensors 8 and 9 of the two hydraulic chambers 5 and 6 of the hydraulic cylinder 4 are compared discretely with a pressure range set beforehand in a pressure monitoring part 31 of a servo control device 12. When the pressures are determined as being within a normal zone, a hydraulic system is judged to be in a normal state and transfer is made to a process of injection. When they are determined as being in an upper or lower limit zone of abnormality outside the normal zone, on the other hand, it is judged that abnormality occurs in the hydraulic system, an abnormality signal is outputted and the transfer is stopped.;COPYRIGHT: (C)1995,JPO