SEALING DEVICE AND HYDRAULIC CYLINDER

摘要

PROBLEM TO BE SOLVED: To provide a sealing device capable of preventing a gas from leaking into a first sealing area in which a liquid is sealed and surely preventing the liquid from leaking into a second sealing area in which the gas is sealed and a hydraulic cylinder.

SOLUTION: In this sealing device 50 for preventing a nitrogen gas from leaking into the first sealing area O and an oil from leaking into the second sealing area G, the shape of the lip end of a first seal lip 51 formed on the first sealing area O side and the shape of the lip end of a second seal lip 52 formed on the second sealing area G side are so formed that the thickness of the oil film formed on a sliding portion when the first seal lip 51 is slid on the surface of a piston 32 is thinner than the thickness of the oil film formed on a sliding portion when the second seal lip 52 is slid on the surface of the piston 32.

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