WO2009004035A3 - Device for measuring torque - Google Patents

Abstract

The device (1) for measuring the torque applied to a rotary shaft, particularly a steering column shaft, comprises a first encoder and a second encoder (3, 4), a first sensor and a second sensor (5, 6) which are non-rotary, positioned respectively facing the first and second encoders, a torsion shaft (2) that can be deformed under the action of an applied torque, the first encoder (3) being associated with the torsion shaft (2) near a first end of the said torsion shaft (2), the second encoder (4) being associated with the torsion shaft (2) near a second end of the said torsion shaft (2), the first and second sensors (5, 6) being capable of generating a first analogue output signal and a second analogue output signal, the said signals being representative of the relative angular position of the sensor with respect to the encoder. The first and second sensors (5, 6) comprise at least three detection elements (7-9; 10-12) generating an output signal, sin a1, sin a2, sin a3, sin b1, sin b2, sin b3, the device comprising an electronic processing module (13) capable, from analogue input signals, of calculating the signal S that is representative of the torque applied to the shaft, where S = (∑(ai - bi)2)0.5 where i is the sensor number.