Research On The Dynamic Characeristics Of Tapered Roller Bearings And Vibration Characteristics Of Shafting In The All-Direction Propeller

Having good abilities of stabilizing attitude, accurate positioning and controlling track, All-direction propeller is the core equipment of the offshore platforms, submersibles, supply ships of the aircraft carrier which can ensure positioning accuracy and stability under severe sea conditions. As an important part of All-direction propeller, dynamic characteristics of tapered roller bearings play an important role on dynamic performance of shafting. However, without fully considering the influences of bearing lubrication film on the dynamic characteristics of rolling bearings, the computational accuracy on shafting vibration issues is sketchy and the research on shafting vibration is difficult to be acknowledged.In this dissertation, to better evaluate the working performance of tapered roller bearings in All-direction propeller, elastohydrodynamic lubrication(EHL) model between rollers and the inner and outer raceways is established. By use of this model, the influence of cone angle of roller, the shape modification of roller and working conditions on lubrication are intensively studied and significant results are obtained. Furthermore, perturbation method is used to deal with the Reynolds equation, which can obtain the film stiffness between rollers and raceways. Then the polynomial response surface is used to fit the film stiffness model. The theoretical formula for calculation of line-contact elastic contact deformation is also derived to obtain Hertz contact stiffness of the tapered roller bearings. Through stress analysis and EHL analysis, analytical model which considers the impacts of lubrication and elastic deformation of bearings is established to calculate the overall stiffness of tapered roller bearings.Based on the overall stiffness model of the tapered roller bearings, the dynamic model of the shafting is constructed by the finite element method. Modal analysis and harmonic response analysis for the shafting and effects of bearing stiffness on the dynamic response of shafting are also conducted in this paper. Moreover, power flow based on the finite element method is calculated, energy transmission and all its influence factors in system under longitudinal or transverse oscillatory force are also analyzed. By minimizing power flow of the propeller, the optimized installation position of bearings in the propeller can also be obtained.