Mechanical Loss Reduction at Thrust Bearings of Scroll Compressors Using R407C

This paper presents the experimental research into high mechanical efficiency at thrust bearings of low-side scroll compressors for air conditioners with the new refrigerant R407C and Polyolester (POE) lubricant. In order to examine the friction loss at the thrust bearing under a test condition which is close to the actual running condition of compressors, the authors developed a friction test machine that could make the orbiting friction test under the pressurized refrigerant atmosphere. Subsequently, an evaluating method of the friction loss at the thrust bearing was established. In the present study, the effects of friction parameters on the friction loss and the coefficient of friction were clarified by evaluating the friction characteristics of the orbiting thrust bearing in the mixing environment of POE lubricant and R407C refrigerant. In addition, above mentioned results of the orbiting friction tests were confirmed by the results of compressor performance tests. As a result, the reduction of the friction loss at the thrust bearing of the scroll compressor was successfully accomplished.