AN UNLOADING HYDRAULIC SYSTEM OF LARGE CAPACITY PRESSURE SENSING TYPE IN CONSTRUCTION HEAVY EQUIPMENT

摘要

The present invention relates to an unloading system for controlling the operating pressure oil of a large heavy equipment using two pumps according to the pressure applied, the first pump (1) through the main hydraulic line (4) and the main control valve The second pump 2 is connected to the main oil pressure line 4 through an auxiliary hydraulic line 6 having a check valve 5, while the auxiliary hydraulic line 6 includes a hydraulic poppet valve ( 7) and the pilot unloading valve 8 are connected in parallel so that the pressure oil discharged from the second pump 2 is operated at its own pilot pressure, and the pilot chamber 9 of the pilot unloading valve 8 is connected. The main oil pressure line (4) is directly connected so that the pressure of the main system is directly applied to the pilot chamber (9), the pressure oil of the second pump (2) is the unloading valve (8) and poppet valve (7) ) To automatically switch to no-load state.