| 摘要 |
A fixed/variable hybrid system has modified constant flow open center hydraulic valves (“fixed/variable valves”), including an open center core, spools, a power core, and a tank galley. A small fixed displacement pump provides fluid at a constant rate to the open center core. A variable displacement piston pump provides fluid directly to the power core as needed. Activation of spools partially restricts the open center core causing an increase in fluid pressure that is communicated to the variable displacement piston pump's load sense signal port, causing the pump to increase fluid flow and pressure to the power core. Activated spools direct pressurized fluid from the power core to the applications through selected hydraulic ports. Activated spools also direct fluid flow from selected hydraulic ports via the tank galley to a hydraulic tank. Pumping the majority of fluid only on an as-needed basis results in significant efficiencies. |
