Mechanical Looseness on a Roller with Pillow Block Housings

The following case occurred on a roller with pillow block housings. Mechanical looseness condition was detected (see Spectrum with 1x harmonics). There was no information about the bearing fits in its assembly. 13 days later, due to an increase in noise, vibration data was collected. There was an important increase in vibration amplitudes, generated by BPFO.

When disassembling, the use of shims in the housing was observed. They had been instaled after the first data collection. This caused the ovality in the housing and an excessive interference fit in the bearing. The ISO15243 standard points out this failure mode due to raceway fatigue at two diametrically locations. This is one of the consequences of not mounting a bearing with the proper fits.