Patent ID: 6282892
Filing Date: 2001-09-04
Classification: F04B,F16D

Abstract:
A pump controller for a construction machine, said construction machine including a variable displacement hydraulic pump, a plurality of control valves connected in series to a center bypass attached to said variable displacement hydraulic pump, and a plurality of actuators to receive and drive a pressure oil whose flow rate and direction are controlled by said control valves, said controller comprising:means for generating a control pressure for negatively controlling a discharge from said variable displacement hydraulic pump, said means for generating a control pressure being installed at a terminal part of a center bypass line extending from a discharge port of said variable displacement hydraulic pump and passing through said center bypass;recognition means for recognizing an operation of each of said actuators;a sensor that converts said control pressure into an electric signal and outputs said electric signal;pump characteristic setting means for storing a pump discharge characteristic for each of said actuators, selecting said pump discharge characteristic corresponding to the recognition of said recognition means and setting said selected pump discharge characteristic;pump discharge calculation means for obtaining a pump discharge in accordance with said electric signal outputted from said sensor and said pump discharge characteristic set by said pump characteristic setting means; andvariable discharge means for converting said pump discharge obtained by said pump discharge calculation means into a pump control signal and outputting said pump control signal to said variable displacement hydraulic pump.