CONTROLLER FOR HYDRAULIC DRIVE MACHINE

摘要

An object of the invention is to improve an operating performance of control levers in hydraulic drive machines. A differential pressure between a discharge pressure Pp of a hydraulic pump (2) and a load pressure Pls of work actuators (3, 4) is varied according to a load on the work actuators (3, 4). Also, the differential pressure between the discharge pressure Pp of the hydraulic pump (2) and the load pressure Pls on the work actuators (3, 4) is varied such that the greater a load Pp on the work actuators (3, 4) and the smaller an engine speed epsilon E, the smaller the differential pressure. The engine speed epsilon E of an engine (1), the discharge pressure Pp of the hydraulic pump (2) and amounts (S1, S2) of operation of respective control levers are detected, and an absorbing torque of the hydraulic pump (2) is set on the basis of the detected engine speed epsilon E and a target engine speed epsilon TH. Thus the differential pressure between the discharge pressure Pp of the hydraulic pump (2) and the load presure Pls on the work actuators is varied on the basis of the respective detected values and a set torque value. The above variation of the differential pressure provides an optimum operating performance of control levers suitable for present working conditions, thus improving a working efficiency greatly.