| 摘要 |
PURPOSE:To raise the performance of steering by a method in which a steering pump and a working machine pump, each of which is driven by the same prime mover, are provided, and when the discharge amount of the steering pump is running short or excessive, the steering pump is mutually connected with the working machine pump. CONSTITUTION:Pressure oil is supplied through a steering valve 3 to a steering cylinder 4 by an oil-pressure pump 2 for the steering of an oil-pressure shovel. By another working machine pump 15 to be driven by the same prime mover 7, the pressure oil is supplied to the main pipeline between a working machine circuit 10 and the pump 2 to control the actuator and the valve 3through a switch valve 13. The pressure oil of the pump 2 is supplied through a control valve 11 to the working machine circuit 10. When the pressure oil fo the pump 2 is running short due to the low speeds of the prime mover, the pressure oil of the pump 15 is supplied through the switch valve and control valve, and also when the pressure oil is excessive, the excess oil is supplied through the control valve to the circuit 10. |
