Hydraulic pump operating device and method for use in hydraulic system

摘要

The rotational frequency of a variable speed motor is set to a normal rotational frequency setting value (N1). A pressure variation range (ΔP) is detected based on a pressure detection value P, of a variable displacement pump, detected by a pressure detector. It is determined whether a determination that the detected pressure variation range (ΔP) is less than or equal to a pressure maintained state detection level (L1) has been continuously given for a period indicated by a timer setting value (T1). If the determination that the detected pressure variation range (ΔP) is less than or equal to the pressure maintained state detection level (L1) has been continuously given for the predetermined period, then it is detected that the current state is a pressure maintained state, and the rotational frequency of the variable speed motor is switched from the normal rotational frequency setting value N1 to a pressure maintaining rotational frequency setting value (N2(

主权项

1. A hydraulic pump operating device for use in a hydraulic system, the hydraulic system including:
a variable speed motor; a hydraulic pump driven by the variable speed motor; and a pressure detector configured to detect a discharge pressure of the hydraulic pump, the hydraulic pump operating device comprising:
a pressure variation range detector configured to detect a range of variation of the discharge pressure detected by the pressure detector;a speed controller configured to control the speed of the variable speed motor based on the detected range of variation of the discharge pressure; anda pressure maintained state detector, the pressure maintained state detector being configured to detect a state where the discharge pressure is maintained, based on the range of variation of the discharge pressure which is detected by the pressure variation range detector;wherein the speed controller decelerates the variable speed motor in response to the pressure maintained state detector detecting the state where the discharge pressure is maintained.