| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To individually measure a flow rate to a hydraulic actuator and a flow rate from the hydraulic actuator. <P>SOLUTION: A valve assembly controls fluid flow between first and second ports of the hydraulic actuator and each of a supply line and a return line. A first electrohydraulic proportional valve is connected between the supply line and the first port, and a second electrohydraulic proportional valve is connected between the supply line and the second port. A first counterbalance valve couples the second port to the return line and operates in response to pressure created by the first electrohydraulic proportional valve and the first port. A second counterbalance valve couples the first port to the return line and operates in response to pressure created by the second electrohydraulic proportional valve and the second port. Thus operation of the first counterbalance valve is slaved to the first electrohydraulic proportional valve, and the second counterbalance valve is slaved to the second electrohydraulic proportional valve. <P>COPYRIGHT: (C)2008,JPO&INPIT</p> |
