Patent ID: 9506738
Filing Date: 2016-11-29
CPC Classification: B60T,G01B,G01D,G01R

Claim Text:
1. A rotation detector comprising: a rotating unit; a magnet disposed on the rotating unit; an angle detecting unit configured to detect a change in angle of rotation of the rotating unit by detecting a leakage magnetic field from the magnet; and at least one position detecting unit configured to operate when the magnet reaches a predetermined position, wherein the magnet has two end surfaces that are away from a rotation axis of the rotating unit and are oriented in a rotating direction and are magnetized to different magnetic poles, and has a flat surface parallel to a rotation plane including a rotation path of the rotating unit, wherein the angle detecting unit is disposed away from a revolution path of the magnet in a radial direction of the revolution path, the angle detecting unit includes a magnetoresistive element including a free magnetic layer, a direction in which magnetization of the free magnetic layer changes is set so as to be parallel to the rotation plane, and the magnetoresistive element is operable to detect a change in angle of rotation of the rotating unit, and wherein the at least one position detecting unit is disposed away from the flat surface of the magnet in a direction parallel to the rotation axis of the rotating unit and includes a magnetoresistive element and a switch circuit, the magnetoresistive element has a resistance that depends on a change in intensity of a magnetic field component parallel to a direction of a tangent to the revolution path, the magnetic field component is included in a leakage magnetic field in the vicinity of the flat surface of the magnet, and the switch circuit is configured to produce a switch output based on a change in the resistance.