Patent ID: 9528855
Filing Date: 2016-12-27
CPC Classification: G01D

Claim Text:
1. A multi-turn rotation angle detection apparatus comprising: a main shaft gear mounted on a main shaft; a first counter-shaft gear and a second counter-shaft gear adapted to mesh with the main shaft gear; a first counter-shaft and a second counter-shaft adapted to transmit rotations of the first counter-shaft gear and the second counter-shaft gear, respectively; a set of angle detectors including (i) a main shaft angle detector adapted to detect a rotation angle of the main shaft, (ii) a first counter-shaft angle detector adapted to detect a rotation angle of the first counter-shaft, and (iii) a second counter-shaft angle detector adapted to detect a rotation angle of the second counter-shaft, where the main shaft angle detector is adapted to output N cycles of an N-fold angle detection value P a gear mechanism having a teeth number difference of a two or larger integer A between the first counter-shaft gear and the main shaft gear, and a teeth number difference of 1 between the main shaft gear and the second counter-shaft gear, a number of teeth of the first counter-shaft gear being an integer multiple of a product of the teeth number difference of the two or larger integer A and a shaft angle multiplier N of the main shaft angle detector; wherein: a multi-turn absolute rotation angle of the main shaft is determined from rotation angle detection values of the main shaft, the first counter-shaft, and the second counter-shaft; and the multi-turn rotation angle detection apparatus further comprises: