| 摘要 |
PROBLEM TO BE SOLVED: To make damping force on a soft side nearly zero in a damping force control type hydraulic buffer. SOLUTION: A main valve 13 is opened, by pressurizing an oil liquid of a cylinder upper chamber 2A and oil liquid passes through oil passages 6 and 7 during an expansion stroke of a piston rod 4. When a space between ports 20 and 21 is opened by a shutter 22, a back-pressure chamber 17 is pressurized and an opening valve pressure of a main vale 9 is enhanced, and the damping force is becomes shift hard. When the space between the ports 20 and 21 is closed, the brake-pressure chamber 17 is not pressurized, the opening valve pressure of the main valve 13 is lowered, and the damping force is set nearly to zero. During contraction stroke, a main valve 26 is opened by pressurizing the oil liquid of a cylinder lower chamber 2B and the oil liquid passes through the oil passages 8 and 9. When the space between 32 and 33 is opened by the shutter 22, the back-pressure chamber 30 is pressurized, the opening valve pressure of the valve 26 is enhanced, and the damping force is becomes shift hard. When the space between the ports 32 and 33 is closed, the back-pressure chamber 30 is not pressurized and the opening valve pressure of the valve 26 is lowered, and the damping force is set nearly to zero.
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