Patent ID: 7411387

Claim:
A position detection apparatus, comprising: two permanent magnets and one magnetic sensor, wherein the two permanent magnets are arranged with their relative position fixed; the magnetic sensor is placed laterally to the arrangement of the two permanent magnets; the two permanent magnets and the magnetic sensor move relative to each other in a direction parallel to an arranging direction of the two permanent magnets; those surfaces of the two permanent magnets which face the magnetic sensor constitute magnetic pole faces of opposite polarity and the magnetic pole faces are placed with an inward tilt; a magnetic sensing direction of the magnetic sensor is set orthogonally to the arranging direction of the two permanent magnets; the magnetic sensor produces an output corresponding to relative position between the two permanent magnets and the magnetic sensor in the direction of the relative movement; and wherein distance between the center points of the magnetic pole faces of the two permanent magnets is set such that stroke length of the relative movement between the two permanent magnets and the magnetic sensor will be 80% or less of distance between the center points of the magnetic pole faces of the two permanent magnets.