Bearing assembly equipped with rotation sensor to determine rotation and position of rotating element

Abstract

To provide a compact bearing assembly equipped with a rotation sensor capable of detecting not only pulse signals for detecting the number of revolution, but also a home position signal, the bearing assembly equipped with the rotation sensor includes a rotatable member () and a non-rotatable member () with rolling elements () interposed between the rotatable and non-rotatable members () and () to permit the rotatable member () to be rotatable relative to the non-rotatable member (). The rotatable member () is provided with a magnetic encoder () and the non-rotatable member () is provided with magnetic sensors (A) to (C). The magnetic encoder () includes first and second to-be-detected elements (A) and (B) each having a plurality of equally spaced, opposite magnetic poles defined therein so as to alternate with each other in a direction circumferentially thereof. The first to-be-detected element also has a magnetic characteristic disturbing element () provided at a predetermined site on a circumference of the magnetic encoder () for agitating a periodicity of the opposite magnetic poles. The two magnetic sensors (A) and (B) for detecting the first to-be-detected element (A) are spaced in a circumferential direction a distance greater than a circumferentially extending width of the disturbing element (), and are so positioned as to be held in substantially phase-matched relation with a cycle of repetition of the opposite magnetic poles.