A Wireless Sensor Telemeter for in situ Cage Vibration Measurement and Corroboration with Analytical Results

ABSTRACT

This article presents both experimental and analytical investigations on the dynamic behavior of the cage in a ball bearing. For the experimental investigation, a wireless sensor telemeter system was designed and developed to monitor the cage motions. The sensor, which was integrated on the bearing cage, is composed of a commercially available capacitor–inductor (LC) circuit. The LC circuit on the rotating cage was coupled to a transceiver that was stationary and positioned in close proximity to the cage. In order to achieve the objective of the analytical investigation, the explicit finite element method (EFEM) was used to simulate the bearing cage. The EFEM cage model was then combined with the dynamic bearing model to simulate the cage motion during operation. The results from the experimental measurement using the telemeter were then compared with the analytical modeling. The developed telemeter demonstrated the capability of the cage telemeter in detecting various bearing frequencies. These include the cage frequency, shaft frequency, and ball pass frequency on the outer race (BPFO), which was introduced by creating a spall on the bearing outer race. Compared to standard accelerometers that are commonly used to measure vibrations on the bearing housing, the cage telemeter has shown advantages in sensing cage motions and detecting bearing defects regardless of the location of the damage. Analytical simulation using the EFEM cage model correlated well with the experimental results and provided more insight into the bearing cage dynamics.