Hydraulic circuit for heavy construction equipment

摘要

The hydraulic circuit for a heavy construction equipment comprises a work control valve (13) which controls a working apparatus cylinder (2) by supplying or retrieving a hydraulic fluid of a first hydraulic pump (11) through a work unit flow path (14;15); a confluence valve (23) which is installed at a parallel flow path (22) connected with a second hydraulic pump (21) and combines a hydraulic fluid of the second hydraulic pump (21) with the work unit flow path (12) based on a positions switch; a swing control valve (30) which is installed at the parallel flow path (22) and controls the hydraulic swing motor (31;32) by supplying or retrieving a hydraulic fluid of the second hydraulic pump (21) to a plurality of hydraulic swing motors (31,32) which drive the swing apparatus; and a disconnection valve (40) which is installed at a swing flow path (36) connecting the swing control valve (30) and the swing motor (32) and is position-switched when the confluence valve (23) is position-switched for thereby disconnecting the hydraulic fluid supplied to at least one of the swing motors (31;32) and at the same time communicating (h) an inlet and an outlet of the disconnected swing motor (32).