| 摘要 |
PURPOSE:To obtain a torque sensor capable of detecting the direction and absolute value with a high sensitivity, by differentially detecting changes in inductance due to magnetostrictiveness at a multi-thread section with +45 deg. and -45 deg. pitches. CONSTITUTION:A multi-thread 2 is formed on a rotating shaft 1 with a pitch angle 45 deg. and -45 deg. with respect to the thrust direction of the shaft 1. A magnetostrictive Fe based amorphous soft magnetic alloys 3a and 3b are fastened on the thread portions 2a of the multi-thread 2. Coils 4a and 4b are arranged separately outside the alloys 3a and 3b so as to be concentric with the shaft 1. When a right torsion is transmitted to the shaft 1, a strain is generated in an alloy 3b on the +45 deg.-pitched thread portion 2a to reduce the inductance. At this point, the strain generated in the alloy 3a of the -45 deg.-pitch is limited and changes in the inductance is also limited. A differential outputs is obtained between the two coils 4a and 4b at a detection section 5. This produces a torque sensor which capable of detecting the direction of torque and the absolute value with a high sensitivity.
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