| 摘要 |
PURPOSE:To enable a noncontact detection of torque accurately in a wide temperature range by a method wherein a rotating shaft is wound with a thin band made of a magnetic metal large in the magnetostriction constant and the thin band is wrapped with a shape-memory alloy cylinder to be fixed on the rotating shaft. CONSTITUTION:In a method of measuring the torque of a rotor utilizing magnetostriction property of an amorphous magnetic alloy, an amorphous magnetic alloy thin body 12 made of (Fe0.985Nb0.015)81Si6B13 or the like is wound on a rotating shaft 11 and ends thereof are fastened with an adhesive. On the other hand, a sheet of a shape-memory alloy such as Ni-Ti is formed at the temperature above the transformation point to make a cylinder 13 with a diameter D3 smaller than the diameter D1 of the shaft 11 and then, expanded in the diameter at the temperature below the transformation point to make a cylinder 13' of the diameter D3, thus resulting to D3>D1>D2. When the thin band 12 wrapped with this cylinder 13' is heated at the temperature above the transformation point, the cylinder 13' reduces to the first diameter D2 to fix the thin band 12 on the shaft 11. The temperature change of the shaft 11 produces a slack between the thin band 12 and the shaft 11 to change the stress working on the thin band 12 due to the torque of the shaft. This prevents deterioration in the detection accuracy of magnetic distortion with respect to the thin band 12. |
