| 摘要 |
PURPOSE:To control a discharge quantity of a variable displacement pump to an optimum according to the capacity of a hydraulic pump by mounting a pressure transducer between a circuit on the discharge side of another hydraulic pump driven with an engine and a regulator controlling the variable delivery pump. CONSTITUTION:When the circuit of a hydraulic pump 3 side is not used, relation of the discharge quantity Q and the pressure P of a variable displacement pump 2 is instituted as the line A according to engine power characteristic. When the circuit of the hydraulic pump 3 is used, pressure on the discharge side circuit 5 is raised, and transmitted to the pressure receiving part 4a of a regulator 4 through a pressure transducer 6. Also pilot pressure is transmitted from the pilot line 9' side to the regulator 4, and the discharge quantity of the variable displacement pump 2 is reduced. Relation of the discharge quantity and the pressure of the variable displacement pump 2 is instituted as the line B according to the discharge pressure of the hydraulic pump 3. Hereby, the sum of the power of the hydraulic pump 3 and the power of the variable displacement pump 2 does not exceed the engine power. The pressure transducer 6 outputs reduced oil pressure corresponding to area ratio. |
