Patent ID: 9379598
Filing Date: 2016-06-28
CPC Classification: G01B,G01D,H02K

Claim Text:
1. An absolute encoder device comprising: a permanent magnet fixed to a rotation shaft, including a first magnetic pattern formed of two poles and a second magnetic pattern formed of a plurality of poles; a first magnetic sensor for detecting a magnetic field of the first magnetic pattern; a second magnetic sensor for detecting a magnetic field of the second magnetic pattern; a signal processing circuit for obtaining an absolute angle signal indicating an absolute angle position of the rotation shaft based on an output signal of the first magnetic sensor, obtaining a relative angle signal indicating a relative angle position of the rotation shaft based on an output signal of the second magnetic sensor, and calculating an absolute rotation angle of the rotation shaft based on the absolute angle signal and the relative angle signal; and a single substrate arranged to be opposed to the permanent magnet so as to fix the first magnetic sensor, the second magnetic sensor, and the signal processing circuit, wherein the first magnetic pattern is formed to have different magnetic polarities along a rotation direction on a plane extending in a direction crossing an axial direction inside a recess formed in a surface of the permanent magnet opposed to the single substrate, and the second magnetic pattern is formed to have different magnetic polarities alternately along a circumferential direction on an outer peripheral surface of the permanent magnet, wherein the single substrate has a flat plane extending in one direction, and the first magnetic sensor and the second magnetic sensor are surface mounting components mounted directly on the same plane, and wherein the first magnetic sensor is received within the recess formed in the surface of the permanent magnet.