Patent ID: 9429231
Filing Date: 2016-08-30
CPC Classification: F15B,F16H

Claim Text:
1. A flushing circuit for a hydraulic cylinder drive circuit, comprising: a hydraulic pump connected to a tank of hydraulic oil to generate pressurized hydraulic oil; a hydraulic cylinder including a piston which slidably enters a cylinder main body and to which a piston rod is fixed and a head-side pressure chamber and a rod-side pressure chamber which are formed by the piston and the cylinder main body; a multifunction valve including: a control valve unit including: a pump-side bypass circuit bypassing the control valve unit and including a pump-side stop valve which has an opening and closing function and connects a pump-side branch circuit branching from a pump discharge circuit of the hydraulic pump with the head-side supply/discharge circuit; and a tank-side bypass circuit bypassing the control valve unit and including a tank-side stop valve which has an opening and closing function and connects a tank-side branch circuit branching from a tank circuit connected to the tank with the rod-side supply/discharge circuit, wherein, a flushing circuit for returning discharge hydraulic oil of the hydraulic pump to the tank is constructed by the pump-side bypass circuit, the bypassing circuit, and the tank-side bypass circuit.