Patent ID: 7076395
Filing Date: 2006-07-11
Classification: B62D,G01D

Abstract:
1. An angle detection apparatus having a resolver that has a transformation ratio, wherein, based on an output signal from the resolver, the angle detection apparatus detects an absolute angle of a rotary shaft that has a switchover point of absolute angles in a single rotation, wherein the resolver includes: a rotor core that rotates integrally with the rotary shaft and has a rotor coil, the rotor coil being excited with an excitation signal having a predetermined amplitude; and a stator core that is located outside the rotor core, wherein a sensor coil is wound around the stator core, the sensor coil outputting an output signal having an amplitude that is proportionate to the amplitude of the excitation signal, wherein the resolver is configured such that, in response to rotation of the rotary shaft, the relative positions of the rotor core and the stator core along an axial direction of the rotary shaft change, wherein the transformation ratio is changed according to changes in the relative positions; wherein the angle detection apparatus further comprises: a multiple rotation amount computation section that computes a first multiple rotation amount of the rotary shaft based on a change in the transformation ratio; a multiple rotation amount accumulation section that detects the switchover point, thereby accumulating a second multiple rotation amount of the rotary shaft; and an abnormality determination section that performs abnormality determination of the angle detection apparatus based on whether the first multiple rotation amount and the second multiple rotation amount are equal to each other.