The texture depth of the inner thread of the floating ring bearing can change the oil film thickness in the texture area,resulting in the change of the dynamic characteristics of the oil film of the floating ring bearing,thus affecting the operating stability and working life of the turbocharger rotor-bearing system.Based on the fluid lubrication theory,the governing equation of oil film of floating ring bearings with surface texture was derived,and the relationship between the texture depth of inner thread and the oil film characteristics of floating ring bearing was revealed.Taking a certain turbocharger floating ring bearing as an example,the effect of the texture depth of the inner thread on the maximum oil film pressure,oil film bearing capacity,stiffness and damping of the bearing was analyzed.A dual oil film lubrication model of the floating ring bearing was established,the dynamic characteristics of the oil film was analyzed by CFD method,and the characteristics of the oil film were studied when the texture depth increases from 6 μm to 12 μm.The results show that the maximum oil film pressure,the bearing capacity of inner and outer oil film,the stiffness and damping coefficient increase first and then decrease with the increase of texture depth in the range of journal rotation speed from 1×103 r/min to 2.1×105 r/min.The effect of texture on dynamic characteristic coefficient of oil film is more obvious when the speed exceeds 1×105 r/min.Compared with the non-textured bearing,the dynamic characteristics such as oil film bearing capacity,stiffness and damping have the largest improvement when the texture depth is 8 μm.It is concluded that under the proper texture depth,the texture can improve the oil film characteristics,improve the running stability of the bearing and prolong the working life.