The technology practiced by MagCanica is well suited to be tightly integrated into the final installation given that the shaft that transmits the torque is the primary transducer. Because of the fact that the torque sensor system leverages the shaft that transmits torque as the primary transducer, when discussing a new application with MagCanica, the shaft characteristics and operating stresses are the top priority. These topics include:
While the materials that work well with the torque-transducer are common in the automotive and aerospace industries, it is not common that the existing shaft is both made of such a material and has an appropriate geometry for the torque-meter. It is more common that certain local geometric modifications are required and a custom shaft has to be manufactured.
It is difficult to provide a definitive list of materials or immediate answer as to whether a particular shaft will work for a given application; however there are several basic trends that can be used to provide an initial assessment. The chemical composition of the material requires at least a small percentage (>2%) of Nickel and / or Chromium. As these percentages increase, so does the magnetostriction (to a point at which it starts to decrease and then actually invert). The increasing magnetostriction increases the sensitivity of the transducer to applied torque, however, limits the peak stresses the materials can tolerate while maintaining ideal magnetoelastic characteristics. Additional factors that have a significant impact include the heat treatment, surface treatment, and specific shaft geometry. We have 20+ years’ experience assisting with the choice of materials, heat treatments, and geometries. Please consult with MagCanica to either help assess whether a material is suitable or help choose the best material for a specific application.
Once the material and stress range are agreed upon, the typical steps towards designing and delivering a torque-meter are as follows: