| 摘要 |
PROBLEM TO BE SOLVED: To reduce hysteresis more than in a conventional sensor. SOLUTION: A magnetostrictive torque sensor 10 includes a sensor shaft 12 of which magnetic characteristics change depending on applied torque, an exciting means (an excitation circuit 14 and excitation coils 161, 162) for applying an AC magnetic field to the sensor shaft 12, and a detecting means (detecting coils 181, 182, and a signal processing part 20) for detecting the torque based on the change in the magnetic characteristics of the sensor shaft 12. An excitation frequency lies between a first frequency and a second frequency. the first frequency is a value where the hysteresis is zero at a first torque value not less than a rated torque value. The second frequency is a value where the hysteresis is zero at a second torque value not more than the first torque value and having a maximum hysteresis when the AC magnetic field of the first frequency is applied.
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