Patent ID: 8659290
Filing Date: 2014-02-25
Classification: G01D

Abstract:
1. A magnetic pole detection system comprising: a magnetic pole array including a plurality of magnetic poles of N and S arranged alternately, wherein the magnetic poles of N comprise two different size magnets and the magnetic poles of S comprise the same two different size magnets, and the sizes of the magnets vary in a direction perpendicular to a longitudinal direction of the magnetic pole array; a magnetic sensor array including a plurality of magnetic sensors for detecting a magnetic pole of the magnetic pole array; a phase detection head for detecting a phase regarding one magnetic pole currently being detected by the magnetic sensor array in the magnetic pole array according to a signal from the magnetic sensor array; a pitch identification unit for identifying a pitch number of the magnetic pole currently being detected in the magnetic pole array, based only on current detection data regardless of historical detection data; a plurality of marks arranged in parallel with the magnetic pole array, changing synchronously with the magnetic poles of the magnetic pole array; and a mark sensor array including a plurality of mark detection sensors provided in parallel with the magnetic sensor array, wherein the pitch detection unit identifies the pitch number of the magnet pole in the magnet pole array based on a combination of signals from the mark detection sensors, and the marks are configured at least by the magnetic poles of the magnet array extended in the direction perpendicular to the longitudinal direction in which the magnet poles of the magnet array are arranged and magnetic poles of the magnet array un-extended in the perpendicular direction.