Fault signature enhancement and skidding evaluation of rolling bearing based on estimating the phase of the impulse envelope signal

Rolling bearing skidding can seriously affect the service life and aggravate the performance degradation process of rolling bearings. Once skidding occurs under variable speed and load, the movement of rolling elements relative to the inner and outer rings is no longer strictly pure rolling. As a result, the speed of rolling bearing cage becomes more complex. In this case, fault signature extraction tends to be more difficult, especially under the condition of variable speed. Although order tracking can solve the problem induced by variable speed to a certain extent, order deviation and vagueness question in envelope order spectra caused by skidding still needs to be further explored. In view of this, an order tracking method based on accurate estimation of impulse envelope phase is proposed. This method can restore the non-periodic impulses caused by skidding to the periodic ones so as to enhance the fault signatures. Besides, the method is capable of evaluating the severity of skidding of rolling bearings by calculating skidding rate, which will be useful for evaluation of bearing performance degradation. Finally, the proposed method is validated by simulation signal and real data of faulty rolling bearings. The results show that the proposed method is efficient to enhance the fault signature and evaluate the skidding rate simultaneously.