| 摘要 |
PROBLEM TO BE SOLVED: To provide a fault diagnosis device for hydraulic equipment for setting a drain amount at a hydraulic circuit to a suitable normal value to reduce loss of entire device under application of a spool valve having a spool position sensor.SOLUTION: A hydraulic cylinder 61 is operated to cause an upper die 62 to descend to depress a work-piece 64 installed at a lower die 63, and a spool valve 65 having a spool position sensor is connected to a hydraulic supply passage (oil passage) of the hydraulic cylinder 61. A reference number 66 denotes a relief valve for determining maximum pressure of the entire circuit, a reference number 67 denotes a change-over valve for on-load un-load states, a reference number 68 denotes a change-over valve for pressurizing and descending and rapid descending of the hydraulic cylinder 61, and a reference number 69 denotes a safety valve to avoid abnormal pressure in the hydraulic cylinder 61. A reference number 70 denotes a counter-balance valve to assure a back-pressure occurred at the time of descending of the hydraulic cylinder 61 and prevent its dead weight dropping. A reference number 71 denotes a hydraulic source.SELECTED DRAWING: Figure 1 |
