| 摘要 |
<P>PROBLEM TO BE SOLVED: To predict an abnormality of a radiator fan or the like causing an emergency stop before an emergency stop of a hydraulic unit. Ž<P>SOLUTION: The hydraulic unit is equipped with an oil tank 11, a hydraulic pump 13 driven by a variable pump motor 14 and supplying a hydraulic fluid of the oil tank 11 to an actuator, and the radiator fan 24 for cooling the hydraulic fluid of the oil tank 11. The unit is equipped with a PQ control part 31 or the like switching the flow rate control operation of controlling the number of revolutions of the pump motor 14 to provide a delivery flow rate of the hydraulic pump 13 at a set flow rate, and the pressure control operation of controlling the number of revolutions of the pump motor 14 to provide the delivery pressure of the hydraulic pump 13 at dead head pressure, and an abnormality warning part 35 predicting an abnormality of the radiator fan 24 or the like when the number of revolutions of the pump motor 14 is deviated from a normal range in a dead head state. Ž<P>COPYRIGHT: (C)2010,JPO&INPIT Ž
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