MECHANISM OF PARALLEL SURFACE THRUST BEARING.

In previous work the pressure generation of parallel surface thrust bearings has been attributed to a thermal distortion of the pad. To clarify the working mechanism of this type of bearing, the variation of the oil film shape has been measured for bearings of different basic thickness using an optical interferometric technique. In addition, a full theoretical computer analysis has been carried out to solve the Reynolds and energy equations together with the elasticity equation, which was derived from a modified two-dimensional finite-element method. Interferograms show a slightly converging oil film in the direction of motion and reveal how the bearing surfaces are distorted because of pressure on the film and temperature distributions. The results calculated by a two-dimensional hydrodynamic analysis show that the minimum film thickness increases in proportion to the cube root or the bearing thickness, and the maximum temperature rise decreases in inverse proportion to the latter. A theoretical analysis of the elastic and thermal deformation indicates that this type of bearing operates by thermal distortion predominantly.