| 摘要 |
<p>PURPOSE:To prevent the loss of energy by raising the running performance of a construction vehicle by a method in which a slewing control valve is connected in tandem to a variable delivery pump, a parallel path is provided, and a selection valve to control the regulator of the pump is controlled by the pressure of the parallel path. CONSTITUTION:A slewing control valve 1 is connected in tandem to a variable delivery pump P and connected with other control valves 2-4 through a parallel path 12. A relief valve 14 of a lower pressure than the set pressure of the running circuit system is connected to the parallel path 12. A selection circuit 19 is provided to the path between a regulator 10 to control the variable delivery pump P and a pilot pump 15. The circuit 19 is operated at near the set pressure of the relief valve 14 in the parallel path to reduce the discharge amount of the pump P. The loss of energy can thus be prevented without the needs to operate the relief valve.</p> |
