Products

Torque sensor

The sensing element is a simple metal wire suspended freely between two points on a shaft along the strain axis of interest, e.g. at 45 degrees to the shaft axis. Excited by common vibrations in the drive shaft the wire vibrates at its natural frequency which is determined by wire stress, wire length and material properties. Application of torque to the shaft increases or decreases the strain in the wire resulting in a corresponding change in its vibrational frequency. A microwave transceiver directed toward the sensing wire emits a high frequency signal and receives the returned signal which is modulated by the vibrations of the wire. Demodulation of the high frequency signal results in a signal corresponding to the wire vibration. This signal is filtered, amplified and analyzed to determine its frequency and thereby the corresponding torque on the shaft.