A new contact amorphous torque sensor with wide dynamic range and quick response

A Torque sensor is described, which uses amorphous ribbons in contact with a sensor head, with a wide dynamic range. A uniaxial magnetic anisotropy Kuo was induced in the (Fe
1-x
Co
x
)
78
Si
8
B
14
amorphous alloy ribbons by magnetic field annealing. These amorphous ribbons, with various Kuo/λ
s
values, were used in order to examine the torsional stress detection characteristics. As expected, a larger Kuo/λ
s
resulted in a wider dynamic range. The wide dynamic range, 1000 μ strain, was obtained in which the detecting torque sensitivity reached a value ten times as high as that for a strain gage torque sensor, using metal resistance film, where exciting frequency (subcarrier wave frequency) f = 5.4 kHz and the exciting current I
p
= 5 mA.