HYDRAULICALLY DRIVEN EQUIPMENT

摘要

PURPOSE:To integrate a relief valve, a check valve and a bypass valve by providing a valve seat of the relief valve slidably so as to use it as the check valve and disposing a plunger which pushes the valve seat in the detaching direction from a valve. CONSTITUTION:A valve seat 15 is disposed inside a valve case 13 of a direct operated relief valve 6 and a valve body 18 which is loaded by a spring 20 is provided inside an internal passageway chamber 17. The valve seat and the valve body 18 make up a relief valve 21. A valve seat 16 is disposed slidably inside the valve case 13. A port 10 at the closed circuit side of the internal passageway chamber 17 of the valve seat 15 has a large diameter and a valve member 15a which is seated on a seat member 13a projected on an inwall of the valve case 13 is formed therein as a check valve 23. A plurnger 24 which pushes the valve seat 15 in the detaching direction from the seat is formed as a bypass valve to bypass a close circuit 3.