Smart bearings: developing a new technique for the condition monitoring of rotating machinery

This paper describes the experimental use of a new technique for the condition monitoring of rolling element bearings. The incremental motion encoder (IME) is a new type of rotary motion sensor that can measure the relative motion between a shaft and its supporting bearing. This motion is directly related to the condition of the bearing. The advantage of this method, over the measurement of transmitted vibration, is that the signal is not attenuated in transmission or distorted by other vibration sources. An experiment demonstrating the ability of an experimental IME device to detect distinct changes in the shaft centre displacement related to bearing corrosion is described to illustrate the IME principle. Based on our work we propose that a bearing constructed with an integrated IME sensor could sense its own condition as well as external factors such as loading and imbalance. A sensor-based or smart bearing of this new type could be an effective condition monitoring and process control sensor for machine tools and other rotary equipment.