| 摘要 |
PURPOSE:To improve operability and profitability by making the minimum discharge of a hydraulic pump for feeding operating oil to a working machine actuator small in regular operation and large in heavy drilling work and the like. CONSTITUTION:A signal corresponding to the operating quantity of a boom lever 1 is outputted to the signal converter 3a of a controller 3 from an electric signal converter 2 and converted to a voltage signal corresponding to the lever stroke. When a signal from the converter 3a is then inputted into the minimum discharge setting device 3c of a hydraulic pump 12, the minimum discharge is set to be a constant stroke or the low minimum discharge S in case of the operating mode being the regular operating mode S. The voltage signal corresponding to the stroke is then inputted into the solenoid 9a of a control valve 9, and operating oil is fed into a control cylinder 10 from a hydraulic power source 8. Moreover, in case of setting the operating mode to the heavy drilling mode G, the minimum discharge is controlled to be the high minimum discharge G. |
