The movement mechanism of thrust collar in the thrust bearing was analyzed to study the coupling effect of the thrust bearing on the radial vibration of steam turbine. The excessively large conical vortex of thrust collar changed the distribution of the oil film thickness in the thrust bearing

then the force of each thrust pad acting on the thrust collar was no longer balanced. Finally

a dynamic reaction force and a dynamic reaction torque were synthesized. As a result

the resultant force of the oil film of the radial bearing supporting the rotor was no longer 0 in horizontal direction

and the resultant force of the oil film also changed in the vertical direction

which further changed the dynamic characteristics of the radial vibration of steam turbine. Combined with the actual engineering cases to verify the relevant theoretical analysis

the results showed that the coupling characteristics of the thrust bearing on the radial vibration of steam turbine were mainly manifested in the ultra-low frequency vibration jump

and the jump amplitude was obviously affected by the axial thrust.