A Study on Contact Force Between Wraps of Scroll Compressor for CO2 Refrigerant

The CO2 compressors have a lot of difficulties to reduce the leakage because of its very high operating pressure. The scroll compressor has two leakage passes, which are the gap in an axial direction at the tip of the wrap and the gap in a radial direction between the wraps. Many attempts to reduce the leakage through those gaps have been actively researched and developed. In this study, we grasped the characteristics of the contact force between the wraps of a CO2 scroll compressor with the fixed-radius crank mechanism by measuring the oil-film pressure at the main bearing. As a result, we found that (1) there is a fluctuation of the contact force at one revolution, (2) the contact force increases with rotational speed and (3) contact force increases with decreasing the wrap clearance ratio.