Magnetostrictive torque sensor

摘要

A noncontacting method for sensing torque based on the principle of magnetostriction which induces a primary magnetic flux in a shaft (20) and obtains a torque dependent secondary signal which is a function of a secondary flux is characterized by obtaining an auxiliary signal via such means as an auxiliary core/coil (48/50) and using that signal with appropriate electric circuitry to eliminate non-torque induced variations in the secondary signal. The first embodiment (Figures 5A and 5B) uses the auxiliary signal to maintain the primary magnetic flux at effectively constant amplitude. The second embodiment (Figures 6A and 6B) divides the secondary signal by the auxiliary signal. A third embodiment (Figure 7) employs a plurality of sensors (66A/66B) strategically located around the shaft (20) to eliminate spurious signals which are due to bending stress and shaft misalignment.