Bearing assembly with built-in absolute encoder

摘要

A bearing assembly (1) of the present invention includes a rolling bearing (1) including a rotatable raceway member (2) and a stationary raceway member (3). This bearing assembly also includes a to-be-detected member (7) carried by the raceway member (2) and having a magnetic characteristic which cyclically varies in a direction circumferentially of the to-be-detected element (7) and has a cycle matching with one complete rotation of the raceway member (2), a magnetic sensor unit (8) carried by the raceway member (3) in face-to-face relation with the to-be-detected member (7), and a magnetic detecting circuit (9) for supplying an electric power to the unit (8) and for processing an output signal from the unit (8) to provide an output to an external circuit. The magnetic characteristic of the to-be-detected member (7) represents a substantially sinusoidal waveform rising and falling more steeply than a sinusoidal waveform at a zero-crossing point.