Development of smart gear system by conductive-ink print (impedance variation of a gear sensor with loads and data transmission from an antenna)

Health monitoring of rotating machine elements, such as gears, is challenging because of rotation at high speed in gearboxes, geometric complexity, or space limitation for measurements. The long-term objective of the present research is to develop smart sensor systems for detecting gear failure signs. As the very first step, we proposed a new method to manufacture electrical circuits, such as sensors or antennas, on gears. We had begun to develop a 4-axis laser printing system and showed the laser sintering conditions of the conductive ink splayed on steel plates insulated by polyimide layers. In this paper, a crack detection sensor was designed and printed. The printed sensor can monitor the condition of a plastic gear whose module and number of teeth are 1.0 mm and 48. In addition, an antenna designed for the same size gear was printed on a plastic plate, and the frequency property of the antenna was investigated. As a result, the printed antenna had the 1st natural frequency at 0.3GHz. Finally, monitoring experiments was carried out to check the condition of a smart system consisting of the sensor and antenna from the other antenna having the same dimension. As a result of the experiment, the monitoring of the return loss of the external antenna shows the sensor is healthy or not. The sensor and antenna system will allow for the development of better equipment and detection techniques for health monitoring of gears.