Patent ID: 8001849
Filing Date: 2011-08-23
Classification: G01L,G01R

Abstract:
1. A magnetic torque sensing system, comprising: a shaft member having a longitudinal axis and operably mounted to have a torque applied to said member; said shaft member having a transducer element with at least one magnetoelastic zone, wherein said magnetoelastic zone is either an integrally formed portion of said shaft member or attached to or forming a part of a surface of said shaft member; said magnetoelastic zone being disposed along said longitudinal axis, its magnetic properties operable to vary under applied torque and as a function of a torque applied about said longitudinal axis; a magnetic torque sensor system comprising a first sensor proximate to a peak field strength of said magnetoelastic zone arising from applied torque, and a second sensor placed farther away from said peak field strength than that of said first sensor, thereby said first sensor sensing more magnetic flux than said second sensor; and a signal processing system to which said first sensor and said second sensor are operably associated therewith to either cancel out the effects of any external interfering magnetic flux or the effects of any temperature offset, reduce the effects of any rotational signal output and temperature sensitivity drift, or develop an output signal representing the torque about said longitudinal axis; wherein said first sensor is an active field sensor and said second sensor is a passive field sensor, wherein there is at least one passive field sensor on one side of said active field sensor.