Speed sensing bearing unit

A speed sensing bearing unit comprising:

• a fixed ring having an inner peripheral surface and a pair of outer ring raceways formed on said inner peripheral surface,
• a pair of rotatable inner rings each having an outer peripheral surface and an inner ring raceway formed on said outer peripheral surface corresponding to said outer ring raceways, respectively,
• a plurality of rolling bodies provided between said outer ring raceways of said fixed ring and said inner ring raceways of said inner rings, respectively,
• a pulse rotor supported on one of said pair of inner rings and having an outer peripheral surface,
• a sensor supported by said outer ring between said outer ring raceways to oppose the outer peripheral surface of said pulse rotor,
• said pulse rotor comprising a cylindrical main body of magnetic material having a plurality of through-apertures at evenly spaced intervals in a circumferential direction, and an engaging element of a non-magnetic resilient material formed to be fitted into said through-apertures, and
• said inner rings having axial end portions facing to each other with said pulse rotor fitted over said axial end portion of one of said inner rings,
• the other of said inner rings having grooves formed in said axial end portion thereof on the outer peripheral surface thereof,
• said engaging element having an inner peripheral surface and hook portions protruding from said inner peripheral surface to engage with said grooves formed on said outer peripheral surface of the outer of said inner rings.