| 摘要 |
<P>PROBLEM TO BE SOLVED: To simplify a control valve in which a separate pressure compensating valve and a shuttle valve have a metering orifice in each valve section. <P>SOLUTION: Valves 14-16 of a valve assembly 17 are associated with hydraulic actuators 21-23, and comprise a variable flow source orifice 34a-c between a supply conduit 28 and a summation node 44 coupled to a pump control port 19, a variable metering orifice 45 between the summation node 44 and the associated hydraulic actuators 21-23, and a variable bypass orifice 50a between the summation node 44 and a tank 18. As the valve 14 operates to enlarge the metering orifice 45, the flow source orifice 34a also enlarges, and the bypass orifice 50a shrinks. Those operations vary fluid flow in and out of the summation node 44, which alters pressure applied to the pump control, thereby causing the output of a variable displacement pump 20 to vary as required to drive the associated hydraulic actuators 21-23. <P>COPYRIGHT: (C)2012,JPO&INPIT |
