Analysis of thrust bearing in high-side shell type scroll compressor

• The characteristics of a scroll thrust bearing is analyzed numerically.
• Simplified average Reynolds equation is solved using FEM with real bearing shapes.
• Optimum overturning coefficient for the scroll thrust bearing is suggested.
• Overturning coefficient and thrust load map is proposed for normal operation.

A thrust bearing of a scroll compressor plays an important role in reliability and efficiency of the scroll compressor. In the case of high-side shell type scroll compressors, the back pressure mechanism without tip-seals is adopted for the sealing in the axial direction between a fixed scroll and an orbiting scroll. Therefore, the lower surface of the fixed scroll becomes a thrust bearing, and the shape and boundary conditions of the thrust bearing are changed successively during one cyclic motion of the orbiting scroll. In this study, the pressure distribution on the thrust bearing is analyzed numerically with real bearing shapes and boundary conditions using the Finite Element Method, and then Newton's method is applied to solve three-degrees-of-freedom motion of the orbiting scroll using the theoretical gas forces. From the results of this analysis, the “overturning coefficient and thrust load map” is proposed to ensure the normal operation of the thrust bearing in the high-side shell type scroll compressors.