US 12,320,372 B2
Calibration system and calibration method in hydraulic system
Hideki Nakajima, Akashi (JP); and Koichi Kiyasu, Akashi (JP)
Assigned to Caterpillar SARL, Geneva (CH)
Filed by Caterpillar SARL, Geneva (CH)
Filed on Aug. 29, 2023, as Appl. No. 18/457,775.
Claims priority of application No. 2022-135612 (JP), filed on Aug. 29, 2022.
Prior Publication US 2024/0068492 A1, Feb. 29, 2024
Int. Cl. F15B 19/00 (2006.01); E02F 9/22 (2006.01)
CPC F15B 19/002 (2013.01) [E02F 9/2285 (2013.01); E02F 9/2296 (2013.01); F15B 2211/20546 (2013.01); F15B 2211/20553 (2013.01); F15B 2211/30535 (2013.01)] 2 Claims
OG exemplary drawing
 
1. A calibration system in a hydraulic system of a working machine, the hydraulic system of the working machine includes a variable capacity hydraulic pump whose capacity is variably controlled according to a pump control current value, a flow rate control valve which is provided in a pressurized oil supply path from the hydraulic pump to a hydraulic actuator and an opening area of a supply opening is variably controlled according to a valve control current value, a pressure compensation valve which is provided on an upstream side of the flow rate control valve and is actuated to keep differential pressure before and after the flow rate control valve to be constant, a relief oil path that is connected to an output side of the flow rate control valve to flow a relief output flow rate to an oil tank at low back pressure, the calibration system comprising:
a pressure detection means for detecting pump pressure of the hydraulic pump, and a controller for outputting a pump control current and a valve control current, and calibrating a correspondence relationship between the pump control current value and a pump flow rate of the hydraulic pump,
wherein the controller includes:
a valve control means that calculates the valve control current value corresponding to an output flow rate of the flow rate control valve of an arbitrarily set target flow rate based on calibrated corresponding data of the valve control current value and the output flow rate of the flow rate control valve, and outputs the valve control current value as a calibration valve control current value;
a pump control means that sweepingly increases and outputs the pump control current value in a state of outputting the calibration valve control current value; and
a calibration control means that calculates the pump control current value when a change of the pump pressure in a sweeping increase peaks, and calibrates the pump control current value as the pump control current value corresponding to the pump flow rate of the arbitrarily set target flow rate.