| 摘要 |
PROBLEM TO BE SOLVED: To provide a variable hydraulic system for suppressing the vibrations of a movable member due to discharge pulsation of a pump in the variable hydraulic system provided with a relief valve for changing the valve opening pressure by the movable member that is displaced in accordance with applied aspect of oil pressure from a back pressure chamber. SOLUTION: The relief valve 20 of the variable hydraulic system 10 includes a communicative passage 21C for making an outlet passage 25 communicative with the back pressure chamber 35 during low pressure stage control. By providing such a communicative passage 21C, the pulsation of oil pressure of a discharge side of the pump 13 can be propagated to the back pressure chamber 35 through relieved oil and oil caused to flow into the communicative passage 21C. The communicative passage 21C is provided such that the pulsation of oil pressure acting on the top surface 26D of a sleeve 26 comes in same phase with the pulsation of oil pressure acting on the back pressure chamber 26C. COPYRIGHT: (C)2011,JPO&INPIT
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