SEALING STRUCTURE FOR ROTARY VANE TYPE STEERER

摘要

The arrangement comprises a plurality of oil chambers (7a, 7b, 7c, 7d) partitioned off around the periphery of a rotor (2) disposed in a housing (1) by vanes (5) and segments (25), the rotor (2) being formed with a balance hole (2f) open to the upper and lower end surfaces thereof, an oil passageway establishing communication between the balance hole (2f) and an oil chamber serving as the pressure side for the oil chambers (7a, 7b, 7c, 7d), the inner bottom surface of the housing (1) being formed with an annular slit (11) opposed to the lower end surface (2e) of the rotor (2), the outer periphery of the bottom of the annular slit (11) being formed with an annular groove (12), a ring seal member (13) disposed in the annular slit (11) and formed with a cylindrical portion (13a) fitted in the annular groove (12) and an annular lip (13c) projecting radially inwardly from the cylindrical portion (13a) across the annular slit width, with its front end, in its free state, projecting from the end surface of the cylindrical portion (13a) to the lower end surface (2e) of the rotor (2), the opening of the balance hole (2f) being disposed more inwardly than the inner peripheral edge of the annular slit (11).