Low-loss drive system for two or more pumped hydraulic actuators with IC engine pumps

摘要

The hydraulic fluid is supplied by a first bidirectional pump (15), in parallel with which a second pump (15') also rotates at a controlled speed. Each pump supplies a separate inlet (61.1. or 61.2) of a preferably four-position valve arrangement (59) whose outlets (63.1,63.1' etc.) supply separate double-acting piston actuators (1.1-1.3) and a hydraulic motor (1.4). The pumps are driven by separate motors (19,19') subject to a common control unit (57) containing a driver and processing circuit for each actuator, which has a sensor (39) optionally incorporating a digitiser for signalling the position, speed and/or acceleration of the piston (5) or piston rod (7).