Calibration system and calibration method in hydraulic system

Abstract

Problem: Calibrating a correspondence relationship between a pump control current value and a pump flow rate of the hydraulic pump in a hydraulic system including a variable capacity hydraulic pump whose capacity is variably controlled according to the pump control current value, a flow rate control valve whose opening area is variably controlled according to a valve control current value, and a pressure compensation valve that maintains differential pressure before and after the flow control valve to be constant is made in a precise and simple manner. Solution: The spool valve has a configuration in which the pump control current value is sweepingly increased and the peak of a change of pump pressure during the sweeping increase is calibrated as the pump control current value of the pump flow rate of the target flow rate, with the spool valve held in the aperture area corresponding to the spool valve output flow rate of the arbitrary target flow rate. With the spool valve maintained at an opening area corresponding to an output flow rate of the spool valve of an arbitrary target flow rate, the pump control current value sweepingly increases, and the peak of the change of the pump pressure during the sweeping increase is calibrated as the pump control current value of the pump flow rate of the target flow rate.