Monitoring of double row ball bearing defects by vibration analysis

The service life of a bearing is limited by the surface fatigue of the materials constituting it due to seizure, micro-scaling, micro-cracks, etc. the repetitive passage of the balls on the cage or the bearing tracks in coincidence with the spalling, resulting in a repeated brutal impact of the balls on the bearing cage. This type of impact is characterized by a pulse-type vibration signal that propagates on the ring, then on the external cage of the pulse bearing which becomes the source of amplitude modulation of the random vibration signal. Many methods allow the early detection of bearing anomalies. Their goal is to detect repeated impacts as early as possible. Shows the different stages of degradation of a bearing. For a new or good condition bearing, this is the period during which there are no surface defects and therefore no vibrations. In this case, the vibration signal generated is of low amplitude, both in peak value and in effective value. As soon as the bearing is affected by defects (pitting, streaking, flaking, etc.), it generates periodic shocks of short duration which can be linked to the internal structure of the bearing.