Patent ID: 7339371
Filing Date: 2008-03-04
Classification: G01D

Abstract:
1. A rotation angle detector comprising: a shaft being made with magnetic material; a magnetic flux generation means for generating magnetic flux aligned from a first side to a second side in a perpendicular plane to an axis of the shaft; a magnetic sensor for sensing change in the magnetic flux; and a supplementary magnet, wherein the magnetic sensor is disposed in a space that extends radially-outwardly from an outer surface of the shaft and radially-inwardly from a periphery of the magnetic flux generation means between both ends of the shaft, the supplementary magnet is disposed in a space that extends radially-inwardly from a trace of the magnetic sensor around the shaft, and a rotation angle of the magnetic flux generation means relative to the magnetic sensor is detected by sensing the change in the magnetic flux by the magnetic sensor, the magnetic sensor includes a first sensor and a second sensor, and the second sensor is positioned in an angle of approximately 90 degrees relative to the first sensor in terms of a sensing surface for the magnetic flux, orientation of a pair of magnetic poles in the supplementary magnet is aligned in a same direction with orientation of a pair of magnetic poles in the magnetic flux generation means, and magnetic poles in the supplementary magnet is aligned in a same direction as the magnetic poles in the magnetic flux generation means at an entire circumference.