| 摘要 |
PROBLEM TO BE SOLVED: To determine rotation of a roller as a change of a magnetic field passing through a Hall element by opposedly arranging each of the N poles and each of the S poles in a pair in the radius direction on the roller rolling face. SOLUTION: As to magnetic poles 6 arranged on a rolling face of a roller 4, each of the N poles and each of the S poles are arranged opposedly mutually in the radius direction of the roller 4, and in the circumference direction, the N pole and the S pole are adjacent to each other. In the vicinity of the end face of an inner ring 2, eleven Hall elements 3 are arranged at equal intervals excepting one place along the circumference direction around the axial center of a bearing. When the roller 4 is rotated according to rotation of the bearing (rotation of the inner ring 2), the magnetic poles 6 touching an outer ring 1 and the inner ring 2 are reversed every time when the roller 4 is turned by 60 degrees, and an inverse phase is set, so that the orientation of the magnetic field is reversed. This process is repeated so that wave-form is outputted. In this process, outputs from the respective eleven Hall element 3 are added up by means of an operation amplifier 12 and without respect to a revolution phase of the roller 4, stable output waveform can be provided in compliance with a change of the magnetic field based on a rotating motion of the roller 4.
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