Flexural vibration analysis of an automobile water pump bearing-rotor system with a modified transfer matrix method

The loading, elastic deformation and hydrodynamic film effect at each rolling element-raceway contact of automobile water pump bearing are analyzed. Based on this analysis, the total radial stiffness, angular stiffness and radial damping of the two rolling element rows are modelled. These stiffness and damping are taken into the transfer matrix to evaluate the lateral vibration characteristics of a rotor-automobile water pump bearing system. The natural frequencies, mode shapes and unbalance responses of the system are calculated. The effects of the pulley and fan unbalances on the system response under different spindle speeds are studied. The calculation results show that the unbalance response of the system can be reduced by fixing the pulley and fan with the initial phase difference between their unbalances to be 180 degrees, and by increasing the pulley unbalance appropriately when keeping the fan unbalance constant.