SWING HYDRAULIC PRESSURE CONTROL DEVICE OF WORK MACHINE

摘要

A work machine is provided with a hydraulic pump (1), a swing motor (2) and swing relief valves (3a, 3b). A swing operation amount (P1) of the swing action of the swing motor (2) is detected, as well as the work pressure (P2) supplied to the swing motor from the hydraulic pump (1). A working fluid required flow amount (FR) required by the swing motor (2) is set on the basis of said swing operation amount (P1), and a relief amount (FE) is estimated from said work pressure (P2) on the basis of the override characteristics of the swing relief valves (3a, 3b). The discharge flow of the hydraulic pump (1) is controlled on the basis of the value obtained by subtracting the relief amount (FE) from said required flow (FR).