Large Barkhausen Discontinuities of Amorphous Ribbon with Domain Wall Pinning

Abstract

A magnetic head type torque sensor has the following advantages; easiness of incorporation, noncontact detection, high sensitivity, small size and light weight. On the other hand, two major issues to be considered on this type of sensor are the strong dependence of the sensor output on variation of gap between the sensor head and a torque transmitting shaft due to its off-center motion, and the fluctuation of the sensor output around a circumference of the shaft due to heterogeneousness of magnetic properties on the shaft surface.
Two issues described above, have been overcome by means of the correction of the sensor output at each detecting position using the correction coefficients of the sensor sensitivity and the offset output, and the multi-arrangement of sensor heads around the shaft, respectively. Furthermore, it is shown that the dependence of sensor output on temperature is reduced to one seventh in comparison with a conventional single-head type sensor and this sensor is useful for measurement of combustion torque generated by automobile engine.