| 摘要 |
PROBLEM TO BE SOLVED: To prevent the damage to a packing by providing a piston fitting face with two stripes of annular packing grooves in which a seal ring and a backup ring are fitted, and forming a gap vacant chamber between the grooves and a tapered face on the bottom of the annular groove, and providing a flow path in an annular groove on the side of an accumulating chamber. SOLUTION: Gas is pressed in an accumulating chamber 4, and working fluid acts on a piston 3 to move it in the direction to compress the accumulating chamber 4. Pressure acts on both a working fluid packing 20a to seal a gap between a cylinder 2 and the piston 3 and a gas pressure packing 20b on the side of the accumulating chamber 4, and a seal ring 6 moves in the pressure receiving direction to press a backup ring 7, which is enlarged in an outside diameter by a tapered face 10 and welded to the inner face 2a of the cylinder 2. Thus even when the seal ring 6 deforms elastically, it is prevented from entering the gap. Since pressure fluid in a gap vacant chamber 22 between the packings 20a, 20b escapes through a flow path 11 toward the accumulating chamber 4, accumulated pressure between the packings is dissolved, and the damage of packing can therefore be prevented. |
