| 摘要 |
A hydraulic system having a pump, a power steering valve, a loader control valve and a pressure compensating valve is used to supply fluid under pressure to one or more hydraulic actuators of an earthworking machine to prevent repositioning of those actuators due to hydraulic leakage or leak-down. The pressure compensating valve has two outlets. One outlet, the priority outlet, is joined to the power steering valve, the other outlet is joined to the loader control valve. The pressure compensating valve includes a load sensing line joined to the power steering valve. A hydraulic connection is provided between the priority output of the pressure compensating valve to those hydraulic actuators which are to be protected against leakdown. This connection includes a check valve to prevent reverse flow. Whenever the steering valve is actuated, the priority output from the pressure compensating valve is thus applied to those hydraulic actuators of interest. Thus, the driver of an earthworking machine on which the hydraulic system is installed is free to transport the machine over the open road without fear that one or more of its pivoted components will swing out of their transport position to some other undesired position due to leak-down.
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