Patent ID: 8607648
Filing Date: 2013-12-17
Classification: G01D,G01L

Abstract:
1. A rotation angle detection device that detects a rotation angle of a rotor, comprising: a multi-polar magnet that rotates with rotation of the rotor, and that has at least one magnetic pole pair having a first magnetic force and at least one magnetic pole pair having a second magnetic force; a plurality of magnetic sensors that respectively output sinusoidal output signals having a phase difference with rotation of the multi-polar magnet; a peak value detecting unit that detects peak values of output signals of the respective magnetic sensors; and a magnetic pole pair identifying unit that identifies one of the magnetic pole pairs, sensed by one of the magnetic sensors, which serves as a reference magnetic sensor, based on a combination of the peak values of the output signals of the respective magnetic sensors, detected by the peak value detecting unit, wherein the number of the magnetic pole pairs, the number of the magnetic sensors, an arrangement pattern of the at least one magnetic pole pair having the first magnetic force and the at least one magnetic pole pair having the second magnetic force and arrangement positions of the magnetic sensors are set such that the combination of the peak values of the output signals of the respective magnetic sensors differs among the magnetic pole pairs sensed by the reference magnetic sensor.