| 摘要 |
<P>PROBLEM TO BE SOLVED: To solve the problem that, since a high-pressure seal is adopted in a conventional hydraulic cylinder, its sliding resistance becomes large, and when the conventional hydraulic cylinder is adopted in a vibration test device, it can not be accurately controlled in high speed. <P>SOLUTION: A sealing device for a hydraulic cylinder comprises a journal bearing provided on the piston side of the inner peripheral part of a head cover inserted with a piston rod for movably supporting the piston rod, a seal provided outside the journal bearing, an oil recovering circular groove formed on the inner peripheral part of the head cover between the journal bearing and the seal, a drain line connected to the oil recovering circular groove, and a drain recovering valve provided to the drain line. Thus, during pressure accumulation of the hydraulic fluid in an accumulator, a lost oil amount can be considerably reduced by closing the drain recovering valve provided to the drain line, thereby, the capacity of the accumulator can be reduced. <P>COPYRIGHT: (C)2010,JPO&INPIT |
