Self-powered technologies for smart bearings

As industrial equipment becomes increasingly complex and efficient, smart bearings play a crucial role in monitoring the operating status of mechanical devices, improving efficiency, and extending service life. To achieve long-term stable operation of smart bearings and avoid the issues associated with replacing and maintaining traditional batteries, self-powered technologies have become a research hotspot in recent years. Self-powered smart bearings collect mechanical energy, vibrational energy, thermal energy, and other forms of energy from the surrounding environment and convert them into electrical energy, driving embedded sensors or functioning as self-powered sensors themselves. This enables real-time monitoring of bearing conditions and data transmission. Although significant progress has been made in self-powered technologies, comprehensive reviews that summarize self-powered technologies in the field of smart bearings and provide guidance for future development are still scarce. To fill this gap, this review summarizes five main energy harvesting methods for self-powered smart bearings: electromagnetic generation, piezoelectric generation, thermoelectric generation, triboelectric generation, and tribovoltaic generation technologies. By analyzing the principles, structures, and performances of each technology, this paper explores their applicability and potential in smart bearings and forecasts the future development direction of self-powered technologies for smart bearings. This review provides a reference for the design and application of smart bearings and promotes the widespread use of self-powered smart bearings in industrial equipment health management.