25 Jul 2024


Non-contact torque sensors improve control precision

A cutaway view of Schaeffler’s torque-sensing module

Schaeffler has developed a magneto-elastic torque-sensing technology that converts stresses in a shaft directly into torque signals. Because the torque is recorded where it is applied, the technique is said to allow applications to be monitored and controlled more precisely than other technologies.

Schaeffler claims that the non-contact approach minimises disruptive influences in the drivetrain, such as torsion rigidity, temperature effects and losses. And because it is based on changes in magnetic fields, rather than evaluating angles of rotation, the shaft is not weakened.

The ready-to-fit FAG torque measurement modules can be used in a wide range of applications, with shaft diameters up to 100mm and torque measuring ranges from 100Nm–20kNm. The operating principle results in a high degree of linearity and low hysteresis. Accuracy is claimed to be around 1% of the measurement range.

As well as torque, the modules can measure speed and thus the amount of power being transferred. This allows the load history on bearings and drives to be calculated.

The first applications for the new technology are in the agricultural sector, such as fertiliser spreaders, where they are being used to monitor parameters such as the speed and torque of take-off shafts, and to feed this data to the control system to optimise performance.