New Contactless Torque Sensor Based on the Hall Effect

Measuring and controlling torque in rotary systems is essential to preventing wear, damage, breakage, and other machine malfunctions caused by excessive shaft torque. The classical methods and those currently available on the market utilize systems that must be electrically powered and for which their data must be acquired by collector rings, transformers or telemetry systems. This paper develops a torque transducer for rotating shafts using a new approach that utilizes neodymium magnets and Hall effect sensors. A pair of magnets is attached to the rotating shaft, and a magnetic field measurement system with Hall effect sensors is positioned in a stationary unit close to the shaft. The relative movement between the magnets due to deformation resulting from torsion will increase or decrease the magnetic field strength. By measuring the strength of this resulting field, it is possible to determine the radial deformation of the shaft. Dynamic tests were performed in the laboratory to validate this technique and to compare it with widespread industrial techniques. The results show the efficacy of the technique and point to potential applications of this dynamic torque sensor using the Hall effect.