Measurement of oil film between swash plate and shoe for swash plate type compressor

摘要

The understanding of the lubrication state on sliding parts of swash plate and shoe of swash plate-type compressors is of a paramount importance for the provision of their reliability. The authors attempted to quantitate the thickness of oil film forming in the contact zone between the swash plate and the shoe. The method used consisted in the determination of the thickness of oil films formed between swash plate and shoe from the absolute values of the oil film thickness distribution and the average oil film thickness. Speaking more in detail, the distribution of the oil film thickness was determined by installing an optical system into a gap provided in the swash plate and using a glass surface as one surface of the swash plate and by observing interference fringes of light reflected from the glass surface and the bottom surface of the shoe. The absolute value of the average oil film thickness was determined by measuring the electric resistance between the shoe and the swash plate electrically connected with the piston through the shoe only, the periphery of the piston being made electrically insulating. Obtained results showed that the oil film breakage did not occur from normal operation conditions to conditions of low oil rate and the state of lubrication was good.