SEALING DEVICE FOR RECIPROCATING SHAFT

摘要

[PROBLEMS] To eliminate instability of sealing capabilities and friction characteristics caused by an external pressure entering between an oil seal (1) and a dust seal (2). [MEANS FOR SOLVING PROBLEMS] A sealing device for a reciprocating shaft has an oil seal (1) and a dust seal (2). In the oil seal (1), a main lip (12) is integrally formed on an inner peripheral portion of an inner installation ring (11), and the main lip (12) is brought to be in tight contact with the outer peripheral surface of a reciprocating shaft (113) while being faced to the axially inside of the shaft. In the dust seal (2), a dust lip (22) is integrally formed on an inner peripheral portion of an outer installation ring (21), and the dust lip (22) is brought to be in tight contact with the outer peripheral surface of the reciprocating shaft (113) while being faced to the axially outside of the shaft. An external-pressure seal (16) brought to be in tight contact with the outer installation ring (21) of the dust seal (2) is provided on the oil seal (1). The external-pressure seal (16) can shut off an external pressure entering between the main lip (12) and the dust lip (22).