| 摘要 |
PROBLEM TO BE SOLVED: To increase the difference between low frequency damping force and high frequency damping force, rest a spool even when a fluid force is generated in the carrying of oil in an orifice, without being influenced by this, and prevent the generation of an impact sound when a free piston is returned. SOLUTION: In this hydraulic shock absorber, two oil chambers are partitioned within a cylinder 1, the two oil chambers are opened and closed through a damping valve, a bypass passage R3 allowing the two oil chambers to communicate each other bypass the damping valve is formed, a spool for opening and closing the bypass passage is movably inserted into the bypass passage, the upper surface side oil chamber 6a and back surface side oil chamber R4 of the spool within the bypass passage are mutually connected through an orifice 17c, and a free piston 13 is movably arranged on the back surface side of the spool. A hollow stopper 14 and hollow guides 17, 19 are provided in series in the middle of the bypass passage, the spool is movably inserted into this guide, and the stopper 18 and the guide have a passage and orifice for mutually connecting the upper surface side oil. chamber and the back pressure surface side oil chamber on the spool, respectively. |
