Analysis of lubricating characteristics of rotary compressors for domesticrefrigerators

We investigated the lubricating characteristics between a vane and piston l ubricated with an oil-refrigerant mixture, Theoretical analyses were perfor med using mixed elastohydrodynamic lubrication analysis theory, taking meta llic contacts into account Lubricating conditions were evaluated by compari ng the theoretical results of piston dynamics based an actual surface rough ness distributions measured by SEM, with the experimental results measured under practical operation. We conclude that (1) lubricating conditions betw een the vane and piston can be assumed to be within the mixed lubricating z one, in which the coefficient of friction changes from 0.04 to 0.08, and th e contact force is almost equally supported by oil film and metallic contac t; (2) the coefficient of friction decreases as the contact force increases because the ratio of pressure rise of the oil film to the decrease in clea rance is much greater than that for metallic contact pressure; and (3) in m ixed EHL analysis, it is important not only to measure the actual surface r oughness but also to select the appropriate contact model.