Patent ID: 7372256
Filing Date: 2008-05-13
Classification: G01D

Abstract:
1. A rotation sensor to be mounted to a rotating member for detecting the rotation angle of the rotating member, comprising: a rotor mounted to a rotating shaft and having a conductive sensing unit which varies in width circumferentially thereof; and stationary cores each having an exciting coil being flown with an alternating exciting current for establishing a magnetic circuit with respect to the sensing unit of the rotor and a core body formed of insulative magnetic material for retaining the exciting coil, and being mounted to a fixed member and disposed so as to oppose the sensing unit of the rotor at a distance in the axial direction of the shaft, wherein the core body includes a peripheral wall portion formed in an area of the core body that opposes the sensing unit, the peripheral wall portion not being formed in at least part of an area of the core body that does not oppose the sensing unit, and wherein a width of the sensing unit is adapted to vary arithmetically from a narrowest width portion to a widest width portion of the sensing unit in a circumferential direction such that the areas of the portion of the sensing unit corresponding to the stationary cores vary linearly in proportion to variations in the rotation angle of the rotor and output signals generated by the cooperation between the exciting coil and the sensing unit of the rotor vary linearly in accordance with the rotation angle of the rotor.