A bearing unit for the hub of a motor vehicle wheel

摘要

The unit comprises a stationary race (1) and a rotatable race (2, 3), each defining respective channels (6, 7) for the passage of pressurized air. Two sealing devices (20) are mounted at opposite lateral ends of the races (1) and (2, 3) for delimiting laterally a pressurizable annular chamber (30) communicating with the channels (6, 7). Each sealing device (20) comprises a flexible sealing lip (25) capable of performing airtight sealing action against a respective counterface surface (26) when the chamber (30) is pressurized.