| 摘要 |
PURPOSE:To enhance reliability and stability, by a method wherein additional windings are provided to both terminal parts of an exciting solenoid coil and the distribution of an excited magnetic field is flattened in an axial direction and electric balance is held even when there is slight positional shift in a detection coil. CONSTITUTION:Additional windings 31, 31 are connected to both terminals of an exciting coil 30 to be excited by a high frequency power source 50 and a flat excited magnetic field is formed over the almost entire length of the coil 30. At this time, in such a state that torque T is not applied to a torque transmitting shaft 10, the induced voltages of detection coils 40a, 40b are equal and reverse in polarity to be negated each other. By this addition of the torque T, the permeabilities of magnetostriction materials 20a, 20b, change and the difference between the induced voltages of the coils 40a, 40b is outputted to a detection part 60. By this method, the residual voltages of the coils 40a, 40b are suppressed extremely slightly and the drift of a torque signal is reduced, and reliability and stability can be enhanced.
|
