| 摘要 |
PROBLEM TO BE SOLVED: To suppress generation of abnormal noise in a hydraulic shock absorber caused by discontinuity of damping force, by smoothly opening a suction valve DV without decreasing deflection rigidity. SOLUTION: In this hydraulic shock absorber, dividing the inside a cylinder 21 into upper/ lower chambers A, B through a piston 5 connected to a piston rod 1, dividing the lower chamber and a bottom part chamber C communicating with a tank chamber D through a valve case 115 provided in a lower part of the cylinder, and controlling pressure side damping force in the case of lowering down of the piston rod by a suction valve DV opposed to an upper side opening window 115D of the valve case and a pressure side damping valve BV opposed to a lower side opening window 115C, a plurality of fan-shaped upper side opening windows 115D, surrounded by an upper side boss part 115E formed in an internal peripheral side, a radial window frame 115K connected to an upper end face of the upper side boss part to be extended in a radial direction to an external peripheral side of the concerned upper side boss part, and a circular arc-shaped window frame 115J connected to the radial window frame, is provided to be spaced from an upper side of the valve case with which the suction valve comes into contact, and by shortening a contact length of the arc-shaped window frame of the upper side opening window relating to the suction valve, a valve opening pressure of the suction valve in the case of switching from a contracting stroke to an extending stroke is reduced.
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