| 摘要 |
PURPOSE: To change the flow rate command value of an actuator to lessen automatically at the time of horse power control. CONSTITUTION: A hydraulic drive circuit in the title is provided with flow rate adjusting valve control devices 105, 106 for controlling the drive of flow rate adjusting valves 103, 104 in response to flow rate command values Qref1 , Qref2 outputted from operation levers 6, 7 and potentiometers 107, 108 and a pump rotation control device 110 for controlling a pump delivery flow rate so as to be always kept below the maximum pump input horse power. When the difference between the sum total ΣQref of the flow rate command value and the maximum pump delivery flow rate Qpmax is positive, for example, a correction calculation means for finding out the smaller correction flow rate command value QR1 than the flow rate indication value Qref1 is provided and this correction calculation means includes a ratio calculation means for finding out the ratio α of Qpmax against ΣQref and a multiplication means for multiplying the ratio α by the flow rate command value Qref1 . |
