| 摘要 |
PURPOSE:To detect torque without reference to ambient temperature by sticking two magnetic layers on the outer periphery of a passive shaft, constituting an oscillation circuit by use of a detection coil wound around them, and detecting the torque as a difference in output frequency variation. CONSTITUTION:The 1st and the 2nd magnetic layers 5 and 6 made of high magnetostrictive materials are made magnetically anisotropic at +45 deg. and -45 deg. from a center axis 2. Then, 8a and 8b are wound around the outer periphery of a rotating shaft 1 through a coil bobbin 7 while covering the magnetic layer 5. The conduction time of transistors (TR) 111 and 112 of the oscillation circuit is determined by the inductance of a collector winding, a capacitor, etc., and increases until a collector current can not hold the TRs saturated after the TRs turn on. The applied torque is detected by regarding variation in the magnetic permeability of each magnetic layer which occurs during the torque application as a difference in variation in oscillation frequency between two oscillation circuits, so the torque in both a standstill and a rotation state is detected together with its direction and the influence of bending stress and variation in ambient temperature is eliminated. |
