| 摘要 |
PURPOSE:To eliminate a flow step in a low displacement region by providing leak mechanism for leaking the decrease quantity to the tank side corresponding to the quantity to be decreased of a pump line when a pressure selecting means selects the pump line between the pump line of a variable capacity type pump and the discharge line of an auxiliary pump. CONSTITUTION:There is provided with leak mechanism 30 for leaking the decrease quantity to the tank T side corresponding to the quantity to be decreased, at the time of selecting a pump line 6, in the discharge flow of the pump line 6, when a pressure selecting means 8 selects a discharge line 7 between the pump line 6 and the discharge line 7 of an auxiliary pump 5. This leak mechanism 30 is connected to a by-pass passage 28, provided at a communicating passage 27, for by-passing the pressure selecting means 8. With this constitution, continuity between the discharge flow at the time of selecting the pressure of the discharge line 7 and that at the time of selecting the pressure of the pump line 6 can be ensured. |
