Design of a Vibration and Noise Testing System of Rolling Bearings

In practical engineering, quality control of mechanical components or parts of rotational machinery is quite important. As for rolling bearings, the defects from rolling bodies, internal ring, external ring, and retainer are more focused on. Therefore, in this work, a vibration and noise test system is developed for the defect diagnosis of mechanical components above-mentioned. The key point of designing this test system is to find out potentially existing defects by means of sampling and analysing the vibration and sound signal of rolling bearing while it's running. In the schemes design of the testing system, a precise spindle with hybrid bearings is considered first in order to heavily reduce the effect of running spindle itself on the sampling of vibration and noise signals from rolling bearing. A sound insulation enclosure for testing rolling bearing is designed to obtain effective noise signal due to the defects of rolling bearing's components. Also the influence of the background noise from external environment will be decreased relatively largely. In addition, an acceleration sensor as well as acoustic microphone is placed on the top surface of external ring and close to the end face of the running rolling bearing in a given direction, respectively. Finally, as an example, ensemble empirical mode decomposition (EEMD) algorithm together with conventional or improved wavelet packet decomposition of vibration and noise signals of testing roller bearing is conceived to extract the features of defects involved. By using above algorithm, one may clearly determine which part is related to defect.