Optimum design of tilting pad sliders with one-dimensional continuous surface profiles

Abstract

The effects of one-dimensional continuous surface profiles on the loadcarrying capacity of both infinitely wide and finite tilting pad slider bearings were investigated and compared with results for a conventional flat surface tilting pad. Pressure distributions are obtained by computer-aided finite difference numerical solutions of Reynolds' equation. These pressure distributions are then used to evaluate the location of the pivot position, loadcarrying capacity, flow rate, side leakage, frictional power loss, coefficient of friction and the temperature rise. Results for infinitely wide and finite tilting pad slider bearings are compared with available analytical solutions to confirm their credibility. The optimized tilting pads with proposed surface profiles have considerably higher load-carrying capacity than the optimized flat-faced tilting pad of the same geometry and lubricant properties. The effect of surface profiles becomes more significant for narrow bearings because the rate of increase in load-carrying capacity compared with conventional flat pads increases with any reduction in the L z L x ratio of the pad. The selection of a particular surface profile also depends mainly on the pad dimensions. Charts are presented for the optimum design of tilting pad slider bearings with newly proposed pad surface profiles by furnishing information on pivot location, load-carrying capacity, flow rate, side leakage, frictional power loss and temperature rise. Numerical examples are provided to demonstrate the applications of these design charts in the analysis or synthesis of a tilting pad slider bearing. An analytical solution of Reynolds' equation for an infinitely wide slider bearing is used to calculate the pivot location, load and flow coefficients for the proposed surface profiles and the results are summarized in Appendix A.