摘要 |
Electro-hydraulic systems (10, 110, 210, 310, 410, 510, 610 and 710) control multiple hydraulic motors without objectionable erratic or jerky motion. The system (10) includes a variable displacement pump (20), an electronic controller (30), a direction control valve (40), first and second pump outlet valves (60) and (70), and a fluid reservoir (80). The pump (20) does not require or use a load feedback signal to control pump output. The controller (30) provides electric control signals to a pump control (21) and to individual hydraulic motors (51). A load sense circuit (46) resolves a highest load sense pressure Ps, which is communicated to the first and second pump outlet valves (60) and (70). The first pump outlet valve (60) limits the maximum load sense pressure. The second pump outlet valve (70) limits the maximum pressure differential between the pump outlet and the load sense pressure. |