| 摘要 |
A rolling-bearing unit including a stationary ring, a rotating ring, an annular magnetic tone wheel having a cutout section with cutouts formed at equal intervals at a pitch, and a sensor facing the tone wheel. The sensor comprises a pair of annular or cylindrical permanent magnets arranged concentric with the tone wheel, an annular or cylindrical stator of magnetic material magnetically connected with the permanent magnets and provided concentric with the tone wheel, and an annular or cylindrical coil provided concentric with the tone wheel and proximate a central portion of the stator. Like magnetic poles of the pair of permanent magnets are magnetically connected to opposite ends of the stator. Peripheral faces of either the magnets or ring portions of the stator are formed with alternating recesses and protrusions with the same pitch as in the cutout section of the tone wheel and facing the cutout section of the tone wheel. The phase of the alternating recesses and protrusions of the peripheral face at one axial end of the stator relative to the cutout section is displaced by one half from the phase of the recesses and protrusions of the peripheral face at the other axial end of the stator relative to the cutout section.
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