| 摘要 |
PURPOSE:To reduce the consumption power by selectively feeding the pressure liquid from a plurality of pumps by using a flowing passage switching valve which operates according to the magnitude of the load of a hydraulic equipment and using the flow rate control valve equipped with a droping mechanism. CONSTITUTION:A flowing passage switching valve 12 which selectively feeds the pressure liquid from a plurality of pumps according to the magnitude of the load on the hydraulic equipment side is installed. When the discharge amount increases over a fixed value with increase of the number of revolution of the pump, a flow rate control valve 20 operates to maintain a constant feeding amount, and when the number of revolution increases further, droping action is generated with the variable orifice constituted of the orifice 22 in a main passage 10 and the small diameter part 30 of a spool 21.Thus, the back pressure applied onto the pump side is reduced by reduction of the feeing amount due to the action of the flow rate control valve 20, especially due to the droping action, and the pressure loss due to piping is reduced, and the energy saving effect can be increased further. |
