Hydraulic control apparatus of working machine

Abstract

With respect to a method of controlling a pump flow rate of a hydraulic pump, a method having a small flow rate command value is selected between a pressure feedback control for controlling the pump flow rate based on a set pressure (a cutoff pressure) and a pump pressure, and, an ordinary control for controlling the pump flow rate based on operation information, and in a case that the pressure feedback control is selected, a flow rate increasing control for increasing the flow rate command value after the case with the passage of time is performed.

Description

Technical field The present invention relates to hydraulic control devices in work machines such as hydraulic excavators. Background technique The cut-off control of the hydraulic control device that performs cut-off control of the pump flow rate is performed for the following purpose: in a hydraulic circuit with a relief valve that determines the highest pressure of the circuit, the relief flow rate (the flow rate of the relief valve) Reduce and reduce energy loss. As a technique for performing this cutting control, the following technique is known. (I) The technique disclosed in JP 10-246204 A, that is, in a negative control, a throttle valve is provided on the downstream side of the release valve, and the pump flow rate is reduced when the pressure on the upstream side of the throttle valve increases ( 1st Prior Art). (II) The technique disclosed in JP 2002-038536 A, which detects the temperature of the relief valve and reduces the pump flow rate when the temperature of th...

AI Technical Summary

Problems solved by technology

The object of the present invention is to provide a hydraulic control device for working machines, which can completely solve the disadvantage of the cut-off control, that is, the problem of insufficient driving force, while realizing the improvement of energy efficiency based on the cut-off control, without adding new equipment.

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