Patent ID: 6860159

Claim:
An improved rotation sensor having: a cylindrical first rotor made of an insulating magnetic material, having conductor layers arranged circumferentially, the first rotor being attached to a rotating first shaft at a predetermined axial position; a core body having an exciting coil, the core body being arranged with a space secured in the radial direction with respect to the first shaft; a stator on which the core body is fixed, said stator being fixed to a fixing member; a second rotor having a nonmagnetic metal bodies arranged circumferentially to oppose the conductor layers respectively, the second rotor being attached to a second shaft located adjacent to and rotating relative to the first shaft and being located between the first rotor and the stator; and oscillating means connected to the exciting coil, the means transmitting an oscillation signal of a specific frequency; wherein the improvement comprises: a first guide ring formed on the first rotor and engaged with the stator for guiding rotation of the first rotor with respect to the stator; and a second guide ring formed on the second rotor and engaged with the stator for guiding rotation of the first rotor with respect to the stator.