ROLLING BEARING UNIT WITH ENCODER

摘要

PROBLEM TO BE SOLVED: To prevent rotational speed detection accuracy from deteriorating due to adhesion of a foreign matter by providing a core metal for supporting an encoder on a rotary shaft with a tubular section while covering the encoder thereby preventing adhesion of a foreign matter to the encoder. SOLUTION: The rolling bearing unit with encoder being mounted on a vehicle is constructed by fitting a sealing ring 27, comprising a core metal 28 and a seal rip 29, fixedly to the end side opening of a hub 4a close to a stationary ring 19. The core metal 28 has an annular part 30 and a tubular part 32 wherein an encoder, i.e., a permanent magnet 13a, is fixed to the intermediate part on the inner side face of the annular part 30. Forward half section and forward end of the tubular part 32 closely face the outer circumferential surface of a circular protrusion 22 provided at the coupling part 21 of the stationary ring 19 and the outer side face of the coupling part 21, respectively. Since the permanent magnet 13a is covered with the annular part 30 and the tubular part 32 and a labyrinth is formed between, the permanent magnet 13a is protected against adhesion of a foreign matter, e.g. magnetic powder.