Triboelectric rotational speed sensor integrated into a bearing: A solid step to industrial application

A rotational speed sensor is of great importance for the development of modern industrial automation. The reliability, integration, measuring range and accuracy are key characteristics to its application. We report a triboelectric rotational speed sensor that is integrated into a bearing (TRSS) and is composed mainly of a bearing seat, a bearing, an adjusting ring, a rotor and a stator. The sensor-output stability can be improved significantly by modifying the bearing's structural characteristics. Periodic electric signals are generated by rotating friction between the copper grating on the rotor and a polytetrafluoroethylene film on the stator surface to induce electron transfer on the copper electrode. A comparison of the analysis of the output signal with a commercial sensor proved that TRSS can be used to measure the rotational speed from 10–1000 rpm with an error below 0.3% and an excellent linearity. Therefore, TRSS is reliable and consistent by verifying the measurement accuracy of the sensors with different sizes. We applied this sensor in an industrial application and demonstrated the application prospects of TRSS.