Development of a Contactless Hall Effect Torque Sensor for Electric Power Steering 2006-01-0939
In this paper, we will present an innovative torque sensor design which could be preferably used in Electric Power Assisted Steering (EPAS) application. This torque sensor is a non-contact Hall effect design. The specificity of this structure is its ability to measure the shift angle between two rotating shafts linked by a torsion bar. This measurement is done with stationary electronic components. This unique structure generates enough magnetic flux variation to measure angular shifts from +/-1° to +/-8° with low-cost standard Hall ASICs available from various suppliers. This torque sensor has convinced automotive industry due to its good performances, its compact dimension and a price compatible with the market expectation for this application.
This paper will explain the basic magnetic principle of this torque sensor, the improvements which have lead to a structure compatible with automotive industry requirements, some measurement results and possible sensor integration in the application.