Patent ID: 8368391

Claim:
A stroke sensor that senses a linear displacement amount of a sensed body displaced linearly, the stroke sensor comprising: a magnet magnetized in a direction perpendicular to a longitudinal direction of the magnet; and two magnetism sensitive sections arranged parallel to the longitudinal direction for sensing a magnetic flux formed by the magnet and for outputting electric outputs respectively, wherein the two magnetism sensitive sections are arranged along an arrangement axis parallel to the longitudinal direction and are arranged such that magnetism sensitive surfaces thereof face in the same direction, which is parallel to a cross-section direction of the magnet and perpendicular to the longitudinal direction of the magnet, the magnet is displaced in the longitudinal direction relative to the two magnetism sensitive sections in accordance with the linear displacement of the sensed body and has a magnetism sensitive section facing peripheral edge facing the arrangement axis, along the direction of the magnetization, and the magnetism sensitive section facing peripheral edge is formed in a curved shape such that a correlation between a magnetic flux density on the arrangement axis and a coordinate of the arrangement axis substantially coincides with a sine curve.