Rotary member supporting apparatus

摘要

A sensor rotor unit mounted on a rotary member and cooperating with a sensor to detect the number of rotations of the rotary member includes at least a sensor rotor formed of a magnetic material and having a plurality of concavities and convexities provided at intervals in the circumferential direction thereof, and an annular rust preventing member made integral with the sensor rotor so as to surround the peripheral surface and end surface of the sensor rotor which are opposed to the rotary member.