Patent ID: 7415899
Filing Date: 2008-08-26
Classification: G01L

Abstract:
1. A torque detecting apparatus, comprising: a first shaft and a second shaft coaxially connected through a torsion bar; a cylindrical magnet which integrally rotates with the first shaft, including a plurality of circumferentially aligned magnetic poles; a set of magnetic yokes which integrally rotate with the second shaft, disposed in a magnetic field generated by the cylindrical magnet; a set of magnetic concentrating rings fixedly disposed so as to surround an outer side of each magnetic yoke; and a magnetic sensor disposed between magnetism concentrating projections provided so as to project from a portion of the magnetism concentrating rings and to oppose each other defining a predetermined airgap; wherein a torque applied to the first shaft and the second shaft is detected based on magnetic flux density between the magnetism concentrating projections detected by the magnetism sensor; and the number of magnetic poles n of the cylindrical magnet is a greatest integer that satisfies the following formula that includes a maximum value T