2019 年 64 巻 12 号 p. 747-758
Lubrication mechanism of the vane-top of multiple vane type compressors was investigated to extract dominant parameters deteriorating oil film formation under high suction pressure conditions leading to abnormal wear of the cylinder inner surface. A calculation model was constructed using coupled analysis of the vane-top part and the vane-slot part, in which the mixed lubrication theory was applied. Of the parameters used for calculation of the oil film thickness, the viscosity of the mixture in which the refrigerant is dissolved in oil and the boundary friction coefficient at the vane-slot part were experimentally obtained, and the force from the back-part of the vane and the action force from the gas pressure inside the compression chamber were obtained based on the theory. The proposed calculation analysis was verified by comparing the calculated results of oil film thickness with the separation degree measured by electrical insulating method on the experiments. Besides, the parametric study of calculation analysis revealed that the causes of poor oil film formation at the vane-top under high suction pressure conditions were the high boundary friction coefficient under the starved conditions and the low refrigerant solution viscosity at the vane-top part.
