The Research On The Dynamic Characteristics And Stability For Journal Bearings

Journal bearing is widely used in mechanical equipment as an indispensable part of the rotating machinery.In this paper,the bearing carrying-capacity,deviation angle,dynamic characteristics and stability of the journal bearings were studied.Bearing characteristics were analyzed by the Reynolds boundary conditions and p-?mass conservation boundary conditions.Under the conditions of mass conservation,different cavitation pressure makes carrying-capacity,deviation angle and cavitation ratio change.When cavitation pressure is zero,both have little difference.Due to the friction between the shaft and the oil film in the process of bearing operation,the oil film temperature changes.Considering the thermal effect of the bearing,carrying-capacity becomes small,deviation angle increases.Different inlet oil pressure makes the oil film temperature field change and oil film viscosity change,thereby affecting the bearing characteristics.By the finite difference method to solve the bearing dynamic characteristics,the paper deduced the judgment of bearing stability.Used the critical mass,equivalent stiffness and critical whirl ratio to analyze stable performance under different bearing conditions.Under the conditions of p-? mass conservation boundary,dynamic characteristics change;the larger cavitation negative pressure is,the worse stable performance is.Thermal effect also affects the dynamic characteristics of bearing.Considering thermal effect,it makes the calculation of bearing stability become worse.In this paper,the static-dynamic characteristics and stability of the bearing were analyzed respectively from the aspects of mass conservation and thermal effect of oil film.It provides a theoretical basis for the further research on the design of journal bearings.