Position detecting device

摘要

A first and a second magnet are provided on a movable member so as to oppose to each other across a virtual plane. Each magnet is magnetized in a direction perpendicular to the movable member, so that the same magnetic poles of the magnets are opposed to each other. A hall IC is provided at a position more remote from the movable member than the magnets so as to be movable on the virtual plane relative to the movable member. A Y-parallel area is formed in a space equally distanced from the first and the second magnets, in which magnetic fields of the first and the second magnet rebel against each other, so that directions of the magnetic fields are so made to be in parallel to a stroke direction of the movable member. Robustness for a position gap between the magnets and the hall IC is improved.

主权项

1. A position detecting device for detecting a position of a movable member movable in a linear stroke direction comprising:
a first magnetic-flux generating member and a second magnetic-flux generating member, the first and the second magnetic-flux generating members being provided on the movable member so as to oppose to each other across a virtual plane which is in parallel to the linear stroke direction and perpendicular to the movable member, the first and the second magnetic-flux generating members being arranged with respect to each other in a first direction which is perpendicular to the linear stroke direction, the first and the second magnetic-flux generating members being magnetized in a second direction which is perpendicular to both of the linear stroke direction and the first direction, and a magnetizing direction of the first magnetic-flux generating member being the same to that of the second magnetic-flux generating member; and a magnetic detecting member provided at a position more remote from the movable member than the first and the second magnetic-flux generating members in the second direction, so as to be movable relative to the movable member in the linear stroke direction, wherein the magnetic detecting member has a magnetic sensing surface arranged so as to be perpendicular to the linear stroke direction, and the magnetic detecting member outputs a signal depending on density of magnetic flux passing through the magnetic sensing surface.