CONTROL SYSTEM FOR OPERATING WORK DEVICE FOR CONSTRUCTION MACHINE

摘要

Disclosed is a control system for controlling flow so as to allow simultaneous usage of a parallel flow path and a tandem flow path thereby reducing loss of pressure inside a control valve, when simultaneously operating work devices having different operating pressures. A control system for operating the work device, according to the present invention, provides the control system for operating the work device for a construction machine, comprising: first and second hydraulic pumps that are connected to an engine; a revolution control valve, an arm control valve, and a left driving control valve, which are installed on a first center bypass path of the first hydraulic pump, and each of which is connected via the parallel flow path; a boom control valve, a bucket control valve, and a right driving valve, which are installed on a second center bypass path of the second hydraulic pump, and each of which is connected via the parallel flow path; a pressure generation device; a bleed flow path, which is formed on a control spool at a lower side of a boom of the boom control valve, for maintaining an open state of the second center bypass path without closing same, when the boom control valve is switched so as to lower the boom; and a center bypass switch valve, which is installed on the lowermost side of the second center bypass path and is switched by means of a control signal for switching the boom control valve.

主权项

1. An attachment driving control system for a construction machine, comprising:
an engine; first and second variable displacement hydraulic pumps connected to the engine and a pilot pump; a swing control valve configured to control the drive of a swing motor, an arm control valve configured to control the drive of an arm cylinder, and a traveling control valve configured to control the drive of a left traveling motor wherein the swing control valve, the arm control valve, and the traveling control valve are installed in a first center bypass path of the first hydraulic pump so as to be connected to a parallel flow path, respectively; a boom control valve configured to control the drive of a boom cylinder, a bucket control valve configured to control the drive of a bucket cylinder, and a traveling control valve configured to control the drive of a right traveling motor wherein the boom control valve, the bucket control valve, and the traveling control valve are installed in a second center bypass path of the second hydraulic pump so as to be connected to a parallel flow path, respectively; pressure generation devices configured to output a control signal corresponding to a manipulation amount; a bleed flow path formed on a control spool on a boom descending side of the boom control valve and configured to maintain the second center bypass path in an opened state instead of blocking the second center bypass path when the boom control valve is shifted to descend the boom through the manipulation of the pressure generation device; and a center bypass shift valve installed on a lowermost downstream side of the second center bypass path and configured to be shifted by a control signal pressure for shifting the boom control valve, wherein a hydraulic fluid from the second hydraulic pump flows into the bucket control valve through the parallel flow path and a tandem flow path connected to the second center bypass path when a boom for performing a boom descending operation and an attachment requiring an operating pressure relatively higher than that of the boom are simultaneously driven.