| 摘要 |
PURPOSE:To alleviate an impact force on a vehicle running on a rough ground by providing a throttle means on the way of an oil passage continuous from one side chamber of a piston to the other side chamber thereof and a changeover valve between the oil passage and an oil supply source for controlling the supply, the cutoff and the elimination of a hydraulic fluid. CONSTITUTION:A controller 120 is inputted with signals from a stroke sensor, a vehicle condition sensor and the like, and controls the flow quantity of a hydraulic fluid. Now, if a piston 10b has shifted toward the contracting direction of a hydraulic cylinder 10, the hydraulic fluid is delivered from an upper chamber 10f and flows into a lower chamber 10g via pilot check valves 29 and 28, and the like. In this case, a flow quantity in the lower chamber 10g is less than a quantity delivered from the upper chamber 10f by the volume of a piston rod 10c, and therefore a quantity corresponding to said volume flows into an accumulator 57. Then, the internal pressure of the accumulator 57 gives a rise and the hydraulic pressure of the upper chamber 10f and the lower chamber 10g increases, thereby causing the piston 10b to balance and alleviating an impact force. |
