Patent ID: 7999534
Filing Date: 2011-08-16
Classification: B62D,G01D

Abstract:
1. A rotation sensor comprising: a main rotor which integrally rotates with a rotor to be measured; a sub-rotor which rotates in accordance with rotation of the main rotor with the number of revolutions which is different from that of the main rotor; first detecting means for detecting rotation of the main rotor; and second detecting means for detecting rotation of the sub-rotor, the rotation sensor detecting an absolute rotation angle of the rotor to be measured from a detection signal from the first detecting means and a detection signal from the second detecting means, wherein the respective detection signals obtained from the first detecting means and the second detecting means are cyclically output in accordance with rotation of each rotor, and the following relationship is satisfied: where Tc is a cycle of the detection signal from the first detecting means, and Tm is a cycle of the detection signal from the second detecting means, wherein the following relationship is satisfied: Tx≧1440 degrees where Tx is a common minimum one in respective multiples obtained by multiplying the cycle Tm and the cycle Tc by different positive integers.