| 摘要 |
PURPOSE:To control discharge pressure of a charge pump in accordance with temporally variation of a discharge quantity of a hydraulic pump and to enable to meet a pump discharge quantity rapidly with a charge flow rate, by applying a signal to an external pilot type hydraulic pressure control valve from an arithmetic system. CONSTITUTION:Discharge quantities of a hydraulic pump 1 and a charge pump 7 and discharge pressure of the charge pump 7 are computed by an arithmetic system 14 through which signals corresponding to the discharge quantity of the hydraulic pump 1, the discharge quantity of the charge pump 7 and the discharge pressure of the charge pump 7 are applied to a regulator 13 of the hydraulic pump 1, a regulator 11 of the charge pump 7 and an external pilot type hydraulic pressure control valve 12 respectively. Set pressure of the external pilot type hydraulic pressure control valve 12 is raised consequently when the discharge quantity of the hydraulic pump 1 is increased suddenly, and sudden increase of a charge flow rate becomes possible. |
