Position detection device

Abstract

A position detection device, configured to detect a position of a shaft that moves forward and backward in an axial direction, is provided with an excitation coil that generates an alternating magnetic field; a target fixed to the shaft and interlinked with a magnetic flux of the alternating magnetic field; and a detection coil in which the magnetic flux of the alternating magnetic field is interlinked. The detection coil has a first portion and a second portion in which an induced voltage is generated when the magnetic flux of the alternating magnetic field is interlinked, and a connection portion connecting the first portion and the second portion. The first portion and the second portion respectively extend along a coil longitudinal direction parallel to the axial direction, and at least a portion of each is aligned perpendicular to the coil longitudinal direction. The target has at least one first target portion facing the first portion and at least two second target portions facing the second portion, with the at least two second target portions being spaced apart in the axial direction. An induced voltage generated in the first portion varies with a position of the first target portion with respect to the first portion, and an induced voltage generated in the second portion varies with a position of the second target portion with respect to the second portion. The first target portion is located between the at least two second target portions in the axial direction, and when the shaft is in a central position between one axial moving end and an other axial moving end, the first target portion faces a central part in the coil longitudinal direction of the first portion.