SERIES HYDRAULIC CIRCUIT FOR CRANE WINCH

摘要

PROBLEM TO BE SOLVED: To provide a series hydraulic circuit for crane winches, enabling to give sufficient outputs to hydraulic motors by setting a CHP set pressure to be high when independently driving them, and to prevent the stop of the hydraulic motors due to relief by setting the CHP set pressure to be low when simultaneously driving them. SOLUTION: The series hydraulic circuit for the crane winches comprises a hydraulic pump, a relief valve, the first hydraulic motor on the upstream side for driving the first winch, and the second hydraulic motor on the downstream side for driving the second winch. Herein, a pump pressure detecting sensor Gppis provided for detecting the discharge pressure of the hydraulic pump P, a controller Gt is provided into which pump discharge pressure is inputted from the pump pressure detecting sensor Gpp, and a pressure compensation valve set pressure changing means 20 is provided which uses the controller Ct for controlling the CHP set pressure of first and second capacity control mechanisms C1, C2to prevent the discharge pressure from exceeding target pressure A which is preset to be not higher than relief set pressure of the relief valve V3. COPYRIGHT: (C)2009,JPO&INPIT