| 摘要 |
Cushion chambers ( 8 ) disposed in the vicinity of both ends of a hydraulic cylinder ( 1 ) to throttle inflow or outflow of an operating oil caused by a piston ( 5 ) moving close to a piston stroke end, pressure sensors ( 16, 17 ) to detect pressures in the cushion chambers ( 8 ), and a control valve ( 13 ) disposed in a passage to supply/drain the operating oil to and from oil chambers ( 6, 7 ) of the hydraulic cylinder ( 1 ) for varying a flow amount of the operating oil are provided. A controller ( 9 ) varies an opening degree of the control valve ( 13 ) within a piston stroke end range based upon outputs of the pressure sensors ( 16, 17 ), adjusts a cushion pressure and controls a moving speed of the piston ( 5 ). Thereby deceleration degrees of the piston ( 5 ) can be freely adjusted within the piston stroke end range based upon a change of the operating conditions of the hydraulic cylinder ( 1 ).
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