Study of Mechanical Loss Reduction on Thrust Bearings for Scroll Compressors Using CO_2 Refrigerant

摘要

We have developed a scroll compressor employing CO_2 refrigerant, whose capacity is 9.4 kW. The CO_2 refrigerant has different characteristics from the refrigerants we have used for air-conditioning systems and refrigerators. There is particularly a large difference between the suction and discharge pressures of the CO_2 refrigerant. Therefore a large compression load is applied to the thrust bearing and the lubrication condition of the thrust bearing becomes critical. We have studied the lubrication of thrust bearings theoretically and experimentally. The average Reynolds equation by Patier & Cheng and the solid contact theories by Greenwood & Williamson and Greenwood & Tripp were used. The method of calculation and the adequacy of the calculated results were verified by model elemental experiments. The calculated frictional characteristics have properties similar to a Stribeck curve. The accurate configuration of the wedge film calculated improves the accuracy of the calculated frictional characteristics of the thrust bearing.