A new torque transducer using stress sensitive amorphous ribbons

A new torque transducer of the nonContact type employing the magnetostrictive effect is presented. In this torque transducer, two stress-sensitive amorphous ribbons are glued to a torsion bar which is used as a part of the shaft. Unidirectional magnetqelastic magnetic anisotropy is created in each ribbon in such a manner that one of the anisotropies lies along 45° to the shaft axis and another along -45°. The applied torque is detected as a difference in permeability between the amorphous ribbons by an ac bias field. The amorphous ribbon used in experiments is of Fe-Si-B system whose saturation magnetostriction Xs ≃ 24xl0-6 and IS≃1.5T. With this torque transducer, instantaneous torque as well as static torque is detected with sufficient accuracy. Due to the easy-to-mount structure, this torque transducer is well suited for the torque control application.