Study on vibration mechanism and dynamic characteristics for TBM main bearing defects

Abstract

As the key component of TBM main driving system, the main bearing plays an indispensable role both in its service life and the normal operation of the TBM. While prior investigations predominantly focused on static analyses of the main bearing, only a scant few delved into its dynamic characteristics and the vibration mechanism. In order to explore the dynamic characteristics of TBM main bearing, a comprehensive dynamics model of the TBM main bearing considering local defects is established, the vibration mechanism of the main bearing with local defects is revealed, and the influence of uneven load is investigated. Furthermore, the effects of roller wear and bearing clearance on the vibration response of the main bearing are analyzed, which systematically describes the real motion of the main bearing. Finally, a main bearing scaling test rig is constructed, and the proposed model is validated through experiments and simulations, demonstrating its good accuracy. In addition, the results show that the incremental imposition of uneven load correlated with a rising trend in the root mean square (RMS) value of vibration response. Moreover, maintaining an optimal axial clearance is pivotal in ensuring the reliable operation of the main bearing. The research work in this paper provides theoretical scaffolding for the defect diagnosis of TBM main bearing, whilst also serves as an analytical cornerstone for future explorations into the dynamics of various types of thrust bearings.